BHEL 600 MW Soot Blower

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DIVISION C BOILER MOUNTINGS

VOLUME C1 SOOT BLOWERS LIST OF CONTENTS

Location Description Ref. No. / Drg. No

1610 – 1611 JINDAL ANGUL VOLUME-C1 PAGE 1 Of 1

TAB-1 (1-4)

SOOT BLOWERS

LRD IIE Views 1-00-076-60601

Furnace Temp. Probe Views ( FTP IE- AC) 1-00-076-60602

Wall Deslagger Views ( WB IE ) 2-00-076-60990

Soot Blower Arrangement 3-00-076-60354 TAB-2

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Soot Blower Operations - Emergency Check List Pub. No. 7515

TAB-3 (19-36)

AC Induction Motor(For Soot Blowers) Pub. No. 7506

TAB-4 (37-63)

Soot Blower - General Instructions Pub. No. 7501

TAB-5 (64-91)

Wall Deslagger -Model WB IE Pub. No. 7503

TAB-6 (92-131)

Furnace Temperature Probe Model FTP IE & IIE Pub. No. 7505

TAB-7 (132-193)

LRD IIE Long Retractable Soot Blower Pub. No. 7514

TAB-8 (194-268)

Methods And Procedures For Installation Soot Blowers Pub. No. 7508

TAB-9 (269)

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DURING BOILER HOT CONDITION

P

04 06 07 08 03 09

10

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03 01 C B B F F SECTION-GG 04 E E G G

WALL & SLEEVE SECTION

VIEW-BB DETAIL-C D VIEW-D A VIEW-A SECTION-FF SECTION-EE 02

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1610 - 1611 VOL - C1 TAB - 1

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1610 - 1611 VOL - C1 TAB - 1 - 4

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INSTRUCTION MANUAL

SOOT BLOWER OPERATIONS

EMERGENCY CHECK LIST

PUB. NO. 7515

Bharat Heavy Electricals Limited

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This manual deals with the emergency actions that are to be carried out when an annunciation occurs during Sootblower operation. Even though many protections are available in the sootblower control panel, sometimes it is likely mal-operation can happen. At that time the operating and maintenance engineers may be in search of correct course of action. We hope this manual will help the operating and maintenance engineers to know what safe action they can take to protect the sootblowers as well as the boiler tubes.

The contents of the manual has been carefully prepared. However, it must be understood that no amount of written instructions will replace intelligent thinking and alertness on the part of the operator during an emergency to reason the causes of mal-f unctions and to take ‘immediate remedial actions demanded by the situation.

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SOOT BLOWER OPERATION -EMERGENCY CHECK LIST

The control panel is normally supplied with the following audible and visual annunciations.

The above alarms can be actuated during the operation of (a) long retractable soot blower (b) wall deslagger (c) rotary blower (d), half retractable soot blower and (e) airheater cleaner (retractable). The possible causes and solutions for each of annunciations for long retractable Soot blowers & wall deslaggers are described in this manual. For other blowers, the causes and solutions may be more or less similar to long retractable soot blowers.

S 1.

N o . D escrip tion of annunciation

T yp e o f annunciation

1. S ootblow er jam m ing audible/visual

2. S ootblow er m otor overload audible/visual

3. S ootblow er overrun audible/visual

4. S team pressure low audible/visual

5. S team tem perature low audible/visual

6. S team no flow audible/visual

7. A .C . control supply failure audible/visual

8. S ootblow er sequence

com pletion. audible/visual

9. V alve M otor overload audible/visual

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1. SOOT BLOWER JAMMING

This alarm will be actuated when soot blower gets jammed mechanically in the forward direction. The alarm is given through an instantaneous overload relay which is actuated instantaneously and will reverse the blower to bring to the home position. The instantaneous overload relay will actuate the timer which will be set at 2 secs., normally current will be 105 percent of the rated current.

1.1 Long retractable soot blower Probable causes and solutions for jamming

Sl. No. Probable Causes Solution

(i) Lance tube fouling with the boiler tubes or wall sleeve

During shut down the boiler tubes should be rectified so that a gap of 100-150 mm is kept in between the lance tube OD and the boiler tube OD. Realign any tube obstructing the lance movement.

(ii) Physical obstruction for the travelling carriage in the housing

Check the blower for proper clearance for the travelling carriage. This can be checked only by local operation

(iii) If direction of rotation for traverse

motor is incorrect

Change the power cable loads with power off and run blower again.

(iv) Failure of reverse limit switch Replace the defective switch

(v) Valve stem jammed/pitted Remove the stem and replace or rectify

(vi) Overtightened gland packing in

travelling carriage

Loosen the gland

1.2 Wall Deslagger : Probable Causes and Solutions for Jamming:

(i) Swivel tube fouling with shroud

tube

Position the blower in such a way that the swivel tube does not foul with the shroud tube and the perpendicularityto the water wall is to be maintained.

(ii) Dust accumulation on the guide

rods and the swivel tube

Clean the guide rods and the swivel tube once in a week. If the accumulation of dust is severe, and morefrequent provide additional covers.

(iii) Direction of traverse motor is in-

correct

Change the direction of motor by changing powerleads.

(iv) Wrong setting of limit switches

LSTS and LSTE

Reset the Cam.

(v) Too much of Gland tightness

on wall blower body.

Loosen the gland nuts to have enough freeness.

(vi) Valve stem/pitted jammed Remove the item and replace or

rectify.

'Reset'push button on the panel should be pressed to continue the sequentialoperation after bypassing the faulty blower.

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2. SOOT BLOWER MOTOR OVERLOAD

This annunciation will come on as soon as the motor gets overloaded the traverse motor will get stopped. The thermal overload relay is set to act normally when the current exceeds 105 percent of the rated current. The probable causes and solutions for his are given below :

2.1 Long retractable soot blower - Motor overload- Probable Causes and Solutions :

Sl. No. Causes Solutions

(i) Lance tube fouling with boiler tubes

Same solution as indicated under sootblower jamming.

(ii) Overtightened gland packing Do not overtighten the glands. A slight leakage of steam is allowed. (iii) Wrong overload relay setting Check the overload relay setting and

set the relay at the correct value. (iv) Dust accumulation over the rails Clear the dust and debris.

(v) Wrong motor installation in powerpacks.

Check the overload relay setting and set the relay at the correct value. (vi) Damaged power/control cables

(Short circuit in any two phases in M.C.C. or Terminal box)

Check the power cables. It is likely that cables damage will result in short-circuiting.

(a) Check the power cable from MCC. to blower terminal box. (b) Check the power cable from the motor to terminal box.

(c) Check the terminal box of motor.

(vii) Motor winding fault Refer the motor instructions manual.

2.2 Wall deslagger:

(i) Swivel tube fouling with the boiler tubes

Same solution as indicated under ‘Sootblower jamming’.

(ii) Wrong overload relay setting Do as suggested in 2. 1. (iii) (iii) Short circuit in the powerloads in

M.C.C. or in terminal box

Do as suggested in 2.1 (vi)

(iv) Motor winding fault Do as suggested in 2.1 (vii)

(v) The rack comes out of pinion Sometimes because of loose screws of cams the rotary gear box is

likely to come out of pinion. For this (a) an easy solution would be to put two rubber washers on guide rods. (b) Periodically tighten the cam screws.

(vi) Improper meshing of gears Dismantle the gear box and check

the meshing of gears.

Overload relay should be reset in M.C.C. before operating the same blower. After ensuring the lance of the particular blower is withdrawn to the home position only, the

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3. SOOTBLOWER OVERRUN

The total time for forward and reverse operation of sootblowers is supervised by elapsed timers. When the blower stays for a longer time than its normal working time the blower overrun annunciation will come and will stop automatic sequence operation and at the same time retract the blowers to its initial position. Normally the timer is set in excess by 1 or 2 minutes of blower operating time. The probable causes and suggested solutions are given below

3.1 Long Retractable Soot blower-Soot blower overrun-Probable causes and solutions

Sl. No. Causes Solutions

(i) Faulty reverse limit switch If the blower is not withdrawn auto-matically

Immediate action

Allow the steam flow if the blower is located in hot zone. Send one man for closing the regulating valve manually. Switch off the power,

Then withdraw the lance manually.

Caution

Do not allow the lance inside the boiler for a longer time with blowing medium.

Later

Check the limit switch contacts, spring, etc. If it is in serviceable condition service and put back the switch. If it is not possible then replace the switch with a new one.

(ii) Wrong timer setting Normally the timer is set more than 1 minute than

the operating time. Check the timer setting and set correctly.

(iii) Failure of contactor and contactor reverse (CR) coils

Check the forward and reverse contactor, clean the terminals and' contacts and put back in M.C.C. (iv) Traverse chain failure due to

the weak link

Immediate action :

(a) Allow the steam flow not more than 5 minutes. (b) Wrap a chain or rope around the travelling carriage through a winch. If this takes too much of time, stop the steam flow. By doing so it is likely that the lance may get bent. In case of blowers located in low temperature zones, the steam flow can be cut off just after the jamming has occurred

(c) And now stop the steam flow. (d) Pull out the lance tube.

Later : Replace the damaged chain link,

using connector link.

(v) Traverse Motor shaft breakage Immediate Action :

(a) Cut off power supply.

(b) Allow the steam flow for not more than 5 minutes. (c) Retract the lance, using the hand crank.

Later

Assemble a new motor and check the direction of rotation before the blower is put into operation again.

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Sl. No. Causes Solutions (vi) Burnt out or damaged traverse

Motors.

Immediate Action :

(a) Cut off the power supply.

(b) Allow the steam flow for not more than 5 minutes.

(c) Retract the lance tube using the hand crank, after cutting off steam supply.

Later

Assemble a new motor or repaired one and check the direction of rotations before the blower is put into operation again.

(vii) Thermal overload Relay for traverse motor blows as a result of which the traverse motor stops.

Immediate Action

(a) Cut oft the power supply. (b) Allow the steam flow for not more than 5 minutes.

(c) Retract the lance tube using the hand crank as suggested in 3.1.(i)

Later

Check why the motor has stalled. Find out the cause

3.2 Wall Deslagger:

(i) ‘ LSTR ' limit switch fails to operate or damaged, missing switch arm.

Immediate Action:

(a) Switch off the power supply.

(b) Using the hand crank, withdraw the swivel tube. (Hand cranking is possible with steam on).

(ii) Wrong timer setting Normally the time is set for 120 secs. Check thetimer

setting and set correctly.

(iii) Faulty rotary contactor (CRO) Check the rotary contactor, clean the terminals and

contacts and put back in M.C.C. (iv) Failure of Traverse motor -shaft

or rotary motor shaft

Immediate Action

(a) Switch off the power supply.

(b) Using the hand crank withdraw the swivel

tube. (Withdrawl of swivel tube by hand cranking is possible with steam on)

Later :

Assemble a new motor and check the direction of rotation before ,he blower is put into operation again

(v) Burnt Out or damaged motors Immediate Action :

(a) Cut off the power supply.

(b) Retract the swivel tube using the hand crank.

Later :

Assemble new motors and 'check the direction of rotation before the blower is put into operation again. Reset push button on the panel should be pressed to continue the sequential operation after ensuring the particular blower is in home position. Physical checking is a must.

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4. STEAM PRESSURE LOW

This annunciation will come to the operator as soon as the system pressure is lower than the set value. As soon as the annunciation is received, retract the blower immediately and stop the sootblowing operation. The probable causes and suggested solutions are as follows:

S1. No. Probable Causes Suggested Solutions (i) Multiple leaks in the system Stop the sootblower operation. (a) sootblower valve passing. Later

(b) Sootblower flange leakage. Identify the leakage in the system (c) Drain valve heavy leakage. and attend the leaks. (ii) Mal-functioning of pressure reducing Immediate Action:

valve Stop the sootblower operation. Later :

Attend to this problem. Ref.detailed instructions for trouble shooting of pressure reducing valve. Immediate :

(iii) Hand stop valve partially closed (a) Stop the sootblower operation (b) Open the valve fully.

(c) Then proceed with SB operation.

(iv) Erratic action of pressure switch or Immediate Action:

damaged pressure switch. Sootblowing can be continued by watching the pressure indicator available on the panel.

Later :

Attend to pressure switch or replace with a new one. CAUTION :

Close the steam supply before

attending the work. (v) Broken supply line Immediate :

Stop the sootblower operation. Later :

Close the steam supply.

Repair the failed steam piping. Then proceed with Sootblower operation.

‘Reset’ push button on the panel should be pressed to continue the sequential operation. Physical checking is a must wherever necessary.

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5. STEAM TEMPERATURE LOW

This annunciation is provided so that the operator will be cautioned when the medium temperature is low. It is likely that low steam temperature will cause condensation which will lead to boiler tube wastage. This may be due to inadequate ‘warm up’ and poor insulation. The solutions will be sufficiently warm up the line and ensure sound insulation.

Another cause may be choking in the drain line. The solution would be to remove the condensate properly.

‘Reset’ push button should be pressed after rectifying the fault to continue the sequential operation further.

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6. STEAM NO FLOW

During the operation of the blower, if steam supply is interrupted for a longer time than the set time in the timer, then the annunciation will come, stop the sequence and retract the lance to the home position.

‘Steam no flow’ interlock was caused by failure to turn on the blowing medium approximately 45 secs after a signal was sent to sootblowers.

The probable causes and solutions are as follows :

Sl. No. Probable causes Solutions

6.1 Long retractable sootblower. (i) Missing blowing adjustment bar or broken adjustment bar.

As soon as the alarm is initiated check whether the blower lance is retracted back to the home position bypass the blower and proceed with sequential operation.

Later :

Assemble the blowing adjustment bar. (ii) Mal-adjusted or damaged flow switch

(common for wall deslagger)

If adjustment is to be corrected, correct the switch. If you have found that the switch is damaged then attend to the damage. If it requires longer time proceed with the sootblower operation bypassing the inter-lock. But this can be done only if one or two men are kept near the blower.

(iii) An improper setting in the timer (common for wall deslagger)

Adjust the timer to initiate annunciation after 45 sees.

(iv) Valve not opening due to (applicable for wall deslagger)

(a) missing and damaged pins of valve opening mechanism

(b) Mal-operation of valve operating mechanism

Immediate

If the blower is retracted back then bypass the blower and proceed with, sequential operation..

Later

Check the pins. If any pins have damaged replace them. Check the lever engagement pull tod cam etc. If it is not OK make it sleight.

(c) Overtightened gland packing Check the valve opening and closing. Make the glands loose. Slight leakage is permissible.

d) Stem pitting Before removing the valve close the

steam supply. If the stem pitting is severe replace with a new stem. (e) Missing of valve opening

screw on lever

Check the presence of screw. If the screw is not in position, new screw is to be assembled.

6.2 Wall deslagger Immediate

(i) Missing ramp cam on the rack Make sure the unit is retracted back immediately. Bypass the blower and proceed with sequential operation.

Later :

Check physically the blower and replace new cam.

If the blower has been retracted to the original position, bypass the blower and press the reset button for proceeding with sootblower sequential operation.

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7. A. C. CONTROL SUPPLY/ POWER SUPPLY FAILURE

When the A.C. supply fails during the operation of blowers, an alarm is annunciated. If the sootblowing operation is proceeding at that time, send a gang for withdrawing the blower back out of the boiler. Proceed as follows :

7.1 Long Retractable Soot blower

(1) Send one man for closing the manual operated valve.

(2) Send another man with hand crank. After declutching withdraw immediately.

7.2 Wall deslagger

Send a man with a hand crank to withdraw the lance tube. “Reset” button must be pressed in the control panel before proceeding with the operation after the power is restored.

8. SOOT BLOWER SEQUENCE INTERRUPTION

This annunciation will come to the operator when the blower does not start even after the sequencing signal is given to the other blower to start. If the blower does not start after 10 secs. even after the completion of operation of the previous blower then this annunciation will come. The probable causes and solutions are as follows :

(i) Motor burnt out or damaged

traversing motor

Immediate:

Bypass the blower from sequence operation Press ' reset ' button and proceed with other blower operation.

Later :

Check the motor. If possible repair the same or replace with a new motor.

(ii) Failure of motor starter, broken wires, motor overload.

Immediate:

Bypass the blower from sequence operation and proceed with other blower operation.

Later :

Identify the problem and rectify the system.

(iii) Defective cabling. _Immediate:

Bypass the blower from sequence operation. Press "reset" button and proceed with other blowers operation.

Later :

Identify the problem and rectify the system.

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9. VALVE MOTOR OVERLOAD

This annunciation will come if the main supply valve actuator is overloaded. The probable causes and solutions are as follows :

(i) Too much gland overtightening Ensure correct gland packing and

tightness.

(ii) Score marks on stem Check Recondition/ Replace stem if

necessary.

(iii) Non-release of motor brake Remove the brake mechanism and

service. (iv) Wrong setting of limit switch on the

actuator.

Set the limit switches correction as instructed in 0 & M manual.

(v) Wrong overload relay setting. Check and set overload relay at the

recommended value. (vi) Excessive torque setting of torque

switches.

Set the torque switches at the recommended value as per 0 & M manual No. 7001.

(vii) Jamming of moving components in the guide ways.

Bypass the whole steam line and then do servicing, For detailed

repairing procedure refer the relevant 0 & M manuals.

After attending to the fault, press 'reset' button in the panel before the operation is continued.

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10. PHILOSOPHY OF JAMMING RELAY PROTECTION AND OVERLOAD RELAY PROTECTION IN SOOTBLOWER MCC.

1. Overload protection is for all motors and for all blowers.

2. The setting of overload relay shall be 105% for all the motors for all types of blowers. All

motors in all types of blowers have 110% capacity for 30 mts.

3. The normal loading of motors in all the blowers when the blower is working with steam is

likely to be around 50%.

4. The overloading of motor in LR blowers is expected due to hitting of tubes etc.

5. The overload relay which is set at 105% when about 300% current (starting current) is

flowing will act in about 25/30 secs. (When the relay is hot/ cold).

6. Jamming relay protection is only for long retractable type blowers. The jamming relay

shall be connected in Traverse Motor power line. Jamming relay will act instantaneously.

7. The current setting of the jamming relay shall be 105% of traverse motor rated current.

8. A time delay relay (0-10 secs.) is provided in Jamming relay protection circuit and is set

at 2 secs. This is to avoid the nuisance which may arise due to action of Jamming relay 7during the starting of traverse motor. The starting time of traverse motor is 0.3 sec. The starting current of traverse motor is 3.0 Amps.

9. Jamming relay with its circuitry will act when overloaded to 105% due to overload/

jamming while on forward operation and reverse the blower. Overload relay will act when overloaded to 105% while on traverse operation. The blower stops operating. However the motor is protected.

10. Locked rotor withstand time for traverse motor is 40 secs. in hot and 75 secs. in cold

conditions.

11. Selection of jamming relay and C.T.

CAG 19 English Electric Relay with 5 Amps. operating coil and 20-80%setting range. 5/5A ratio C.T. 5P20, 15VA

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INSTRUCTION MANUAL

AC INDUCTION MOTOR

(FOR SOOT BLOWERS)

PUB. NO. 7506

Bharat Heavy Electricals Limited

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Where the magnitude of the installation justifies the cost, a set of record plans should be provided by the installation engineer or contractor, clearly indicating the complete layout of the installation. There is always the possibility that hair, hands or clothing may be caught in moving parts of electrical machines, which should thus be so located or guarded as to minimize the risk of such injuries to those who may come in contact. In the case of equipment subject to the provisions of the Factories Act such mechanical protection is a statutory requirement.

1.2 STORAGE

If the machine has got to be stored for some time before installation, the same has to be done in a clean, dry place. If the location is susceptible for vibrations transmitted due to working of heavy machinery, proximity to rail track, etc. it is desirable to have a resilient pad between the floor and the machine. Also keep the shaft of the motor locked so that, bearings are not damaged during storage. However, periodically rotate the shaft free and relock it.

1.3 LOCATION OF MOTORS AND CONTROL APPARATUS

Apparatus shall be so located that all current-carrying parts are adequately ventilated in relation to the losses to be dissipated in the form of heat.

Note: In no circumstances should the motor be enclosed in a box or other covering hat restricts or excludes the ventilating air to a significant extent. Such restriction may result in the burning out of the motor when a sustained load approaching the full value is reached. The motor and control apparatus shall not be located where it is liable to exposure to water, corrosive liquid, oil, steam, carbon, copper dust, dirt or other adverse condition or to risk of mechanical damage, unless it is suitably enclosed to withstand such conditions.

Adequate access shall be provided to all working parts. The possible need for facilities for removing the equipment at a later date for repairs or maintenance should be considered in relation to the accessibility of the equipment.

Note: For handling heavy equipment it is often advisable to arrange for the incorporation of a lifting beam in the structure of the building, the beam being located immediately over such parts of the equipment as may require attention and being capable of supporting the maximum weight involved.

The placing of apparatus in situations where inflammable material may be present should be decided in relation to the fire risk involved, and where it is impracticable to segregate the apparatus from such material, the use of totally enclosed or pipe ventilated apparatus should be considered. Where resistors are used which are liable to operate at high temperatures, they should be adequately spaced away from combustible materials such as wood-work, in order to combat the risk of fire. Whenever the temperature of the casing of the apparatus is liable to exceed 194 Deg. F (or 90 Deg.C) the casing should be so located or guarded as to prevent accidental contact by persons or with combustible materials.

1.4 GEAR DRIVES

With gear drives, alignment is equally important. The centre of the pinion shall be in line with the centre of the spur wheel and the two wheels perfectly parallel, the latter being checked by means of feeler gauges between the teeth of the respective wheels. The gear wheels shall be fully meshed both in depth and along their width of face and the check for meshing shall be made all the way round the driven wheel in case it is out of truth. Should the driven wheel be out of truth and the meshing adjusted correctly at the lowest point of the driven wheel, the gears would jam

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Bevel or single helical gears will impose an end thrust on the motor shaft, and are not therefore recommended unless provision is made to take the thrust. Double helical gears may also transmit an end thrust if the end-play in the bearings of the driven gear is greater than the end-play in the motor bearings. Where mechanical conditions are severe it is sometimes necessary, particularly in the case of large motors, to employ an outboard bearing for the motor shaft and in some cases to mount the driving pinion in two separate bearings and couple it to the motor through a suitable flexible coupling. A flexible coupling is invariably necessary when a motor is coupled to a self-contained gear box. It is advisable, when any drives of the above mentioned or similar types are considered, that this be specified so that provision can be made to suit the conditions.

Where motors are fitted with ball and roller bearings, care shall be taken to ensure that no axial strain is imposed on the bearings when the half-couplings are bolted together.

1.5 DRYING OUT

All motors shall be dried out before the full voltage is applied to the terminals, if the insulation resistance is below one megaohm when the machine is cold. A convenient method of doing this is to block the motor so that it can not rotate and apply a very low voltage of about 10 percent of the normal to the stator terminals.

In the case of slip-ring motors, the rotor windings should be short-circuited.

Close supervison is necessary during the process of drying out with this method. The heat generated in the windings is not easily dissipated and one part of the winding may be exceeedingly hot before another part has had time to expel the moisture. This may be obviated to some extent by taking every precaution to exclude draughts from the exposed parts of the windings.

The motor can be placed in oven, if available, but the temperature shall not be allowed to exceed 180 Deg. F (or 82.2 Deg.C). Alternatively, hot air may be blown into the motor but the air should be clean and dry and at a temperature of not more than 180 Deg.F. If no other means are available, coke braziers or electric radiators may be placed round the machine. Carbon filament lamps placed inside the machine can be employed quite satisfactorily, but care shall be taken that the hot bulb is not in contact with any windings. If it is not possible to reach a sufficiently high temperature the ventilation may be reduced by covering the stator with a tarpaulin.

Whichever of the above methods of drying out is adopted, the heating shall be continuous and shall be carefully watched to ensure that it does not attain a temperature sufficiently high to damage the insulation. The maximum safe temperature of the windings measured by thermometer is 180 Deg. F (or 82.2 Deg.C). At the same time the temperature should not be allowed to fall too low as otherwise re-absorption of moisture would take place.

The insulation resistance will be found to drop considerably as the motor warms up, will reach the minimum and then remain constant for sometime depending upon the dampness of the machine and as the drying proceeds the insulation resistance will gradually rise. The drying out shall be continued as long as the insulation resistance rises, or until a sufficiently high value has been reached, i.e. not less than 1 megaohm per 1000 volts at 75 Deg.C.

During the drying out period, readings of temperature and insulation resistance shall be taken atleast once an hour in order to see how the drying out is progressing. The temperature of the motor shall be kept as constant as possible, otherwise the insulation resistance readings may be misleading.

NOTE: The motor should be watched constantly whilst drying out.

1.6 REVERSAL OF ROTATION

Reversal of rotation, if required shall be effected by interchanging two of the three supply leads connected to the stator switch, breaker or starter.

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2. INSPECTION AND TESTING

2.1 GENERAL

All electrical equipment shall be inspected and tested by competent persons at regular intervals, the frequency of such inspection depending on the type of equipment and on the operating conditions. A record of each inspection and of the result of tests should be kept.

2.2 MECHANICAL

Machines shall be checked for alignment to ensure that undue stresses are not imposed on their bearings.

Where oil-lubricated bearings are employed care should be taken to see that oil does not penetrate on to windings or other insulation. In addition clearances shall be kept to reasonably close limits as too large a clearance may affect correct alingment and may cause fouling of the stator by the rotor, whilst too small a clearance may disturb running mechanical balance. Oil should be checked to see that it is clean and up to the right level.

The air gaps in sleeve bearing machines shll be checked before commissioning. This check should be repeated at periodic intervals.

Mechanical operation of motors control gear and protective devices shall be checked for freedom from external material, care being taken when commissioning to see that all packing materials are removed.

In the case of motors and control gear, attention should be paid to all contacts, the contact pressure and contact area being checked and verified as being proper to the operating conditions involved. If ball roller bearing motors have been kept idle for periods longer than six months whether new, spare or stand-by plant, the bearing covers should be removed for inspection of grease. If it is found that the grease has a skin over the surface, the bearings should be washed out thoroughly in kerosene, and three drops of fine oil added to the race. The bearing housings should be repacked with new grease recommended by the makers, care being taken to ensure that the balls or rollers will not churn in the grease. One of the chief functions of grease is to prevent the entry of dust to the races, very little being required for lubrication.

2.3 ELECTRICAL

All fixed connections shall be checked for tightness and where heavy currents are involved a check shall be made to see that contact adequate in area and pressure to prevent undue heating is effected between all contact surfaces.

Before the equipment is put into service, it shall be tested for insulation resistance and other tests as may be necessary should be made. Continuity tests shall be carried out, particular attention being given to the secondary connections of current transformers. Before switching in for the first time, protective devices shall be set at their minimum current values and at the minimum time setting in order to minimise the consequence of any fault condition which may arise. The rating of fuses shall be checked by inspecting the marking on the cartridge-type fuses or inspecting the gauge and type of wire in the case of semi-enclosed type-fuses. Where practicable, the operation of overload, no volt and other types of protective device shall also be checked. The results of such checking should be related to the ascertained resistance of the earth-fault current path so as to determine the prospect of the protective device operating in the event of a fault to earth. Earth leakage protection should be adopted in the following cases:

a. If the ascertained resistance is such as to restrict the fault current to a value below the

operating value of the overload releases.

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c. If, where fuses are used, the resistance is such that sufficiently rapid operation cannot be ensured, and the earthing conditions cannot be improved.

Protective fuses shall be examined regularly, and, as far as possible tested. Where relays are used in conjunction with current transformers, the test should preferably stimulate working conditions by utilizing the injection method whereby current is passed through the relays by the application of a variable injection voltage from a transformer designed for the purpose.

3. MAINTENANCE PROTECTION OF EXPOSED SURFACE

3.1 GENERAL

Protective paint and varnish shall be maintained in good condition by repainting or revarnishing when necessary, it being noted that in many instances, such as that of machine windings, spraying is the only effective means of application of such protection.

MOTOR

Cleaning of Machines

Motor shall be blown out at regular intervals to keep their ventilating passage clear, it being emphasised that many types of totally enclosed motors required such attention, particularly when operating in dusty atmosphere.

Moisture, oil, dirt, grease and carbon or metallic dust are the principal causes of breakdown. The motor should therefore be kept clean and dry; water dropped on the machine will soon cause trouble, unless the motor has been designed to withstand such conditions. The stator and rotor windings must be kept free from oil and grease, damp and dirt. Periodic cleaning with dry compressed air, bellows or a brush, is very necessary.

All motors require to be examined and dismantled from time to time and the frequency of successive cleanings will depend upon the conditions under which the machine operates. During periodic cleanings care shall be taken to clear air passages in the stator and rotor of any accumulated dirt.

Terminals and screw connections shall be kept clean and tight. If they become dirty or corroded, they shall be disconnected and all contact surfaces made clean and smooth. Bad contact leads to sparking and ultimate breakdown.

After reassembly, the gaps shall be tested as a precautionary measure by means of a feeler gauge. If it is found that the air gap measurements of two diametrically opposite points differ by as much as 25% the machine shall be examined, because the brackets or bearing housings will not be correctly aligned. Gap measurements shall always follow reassembly, since rubbing between stator and rotor will cause extensive damage.

3.2 INSULATION RESISTANCE

The insulation resistance of the windings shall be tested periodically during service and where this is found to drop below 1 megaohm/KV with a minimum of 1 Megohm the motor shall be dried out and put in service. If weak insulation, resistance becomes a regular feature the windings shall be given a coat of good insulating varnish after the machine has been dried out. Where the motor is installed in locations, subject to dampness, chemical fumes, etc., the installation indicator such as a neon lamp to show the condition of the insulation of the motors is recommended.

3.3 REMOVAL AND REPLACEMENT OF BEARINGS

In small frame motors, the bearings can be removed with a bearing puller. The cartridge type bearing housing is employed in large frame motors.

After cleaning, the housing should be greased with the specified grade grease and the bearing replaced by applying even pressure to the outer race. Having ensured that the bearing is square with the housing, it may be necessary to tap lightly into position.

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Having ascertained that the outer race beds firmly against the housing shoulder, the whole may be slipped over the shaft which should be cleaned and oiled.

The bearing may now be forced on to the seating by means of a tube placed over the shaft and applied to its inner race; this method ensures even pressure and the bearing may be driven home against its locating shoulder. On no account must the inner race mounted by hitting the outer race and pressure should not be applied to the outer race during the process. The blows should be equally distributed all round the inner race and care should be taken to avoid hitting or applying pressure to the lip of the inner race, in the case of a roller bearing. Otherwise the bearing along with the bearing housing can be heated in medium oil Shell Tellus – 33 Deg. at a temperature not exceeding 100 Deg. C for about one hour to enable easy mounting by push fit.

3.4 BALL AND ROLLER BEARINGS

Climatic conditions affect the lubrication and it is necessary to ensure that the bearings do not run hot. This shall be tested from time to time by placing the hand on the bearing cap. A moderate warmth to the hand is a ready indication that the bearing is running at its best. Higher or lower temperatures are not dangerous in themselves but increasing temperature or noise are sure signs that the bearing needs immediate attention. It may be that the addition of a small amount of grease will arrest and cure the trouble.

When opening up bearings for inspection and cleaning, all dirt and foreign matter shall be removed from the neighbourhood of the bearing caps. The caps shall then be removed and the bearings, caps and housings washed with kerosene, all old grease also being removed in the process and the parts thoroughly cleaned. If the bearing is in good condition, fresh grease shall be pressed well between the cage, races, balls and rollers. We recommend Shell Alvania No.3 grease or it’s equivalent. After packing the bearing, any superfluous grease shall be wiped off. If the bearing appears dirty or if the grease has become hard and disintegrated the bearing shall be removed from the shaft, withdrawn from the housings and closely inspected for signs of wear.

3.5 LUBRICATION

It is often assumed that with the substitution of rolling motion for sliding motion in antifriction bearings, the sources of friction are eliminated and lubrication is of secondary importance. But this is not correct since sliding friction still occurs at the cage which separates the rolling elements or between the element themselves if they are not separated.

The smooth and silent running of antifriction bearings depends to a large extent on the high degree of finish imparted to the tracks and rolling elements, and quite apart from its function of minimising wear on rubbing surfaces, the lubricant is required to protect these highly finished working parts. The rolling element bearings require a small amount of lubricant depending upon the size and type of bearing and generally the lubricating intervals are long. However, lubricant must always be present in the bearings otherwise their lift may be affected or retarded by injuries which could have easily been avoided.

The main functions of lubricant in a bearing are:

i. To provide a separating film between rolling and sliding contacting surfaces, thus pre

venting wear.

ii. To act as a coolant to maintain proper bearing temperature.

iii. To prevent the bearing from being contaminated by dirt and other foreign matter.

iv. To prevent corrosion of bearing surfaces.

When the moving parts of a bearing come in contact with grease, a small quantity of oil adheres to the bearing surfaces. Oil is therfore removed from the grease near the rotating parts. The oil that is picked up by the bearing is gradually broken down by oxidation, or lost by centrifugal

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force, and volatalisation. Bleeding of the Grease therefore takes place to continue the supply of a small quantity of oil, which is usually sufficient for satisfactory operation.

Lithium based Multipurpose Grease conforming to Grade 3 of IS 1002-1956 amended upto date, is recommended for all Rotating machines fitted with antifriction bearings.

The popular greases are:

Shell Alvania (or Multipurpose) Grease 3 Mobilux Grease No.3

Castrol Shperol. AP3

The safe operating temperature range for the above greases is: -130_{F to 248}0_{F (approx. Value)}

The quantity of Grease which should be applied to the inside of the bearing when relubricating is,

D x B

W = —————— x 28.35 Grams 6000

Where D = O.D. of the Bearing in mm

B = Width of the Bearing in mm W = Weight of grease in gm

Running conditions, especially speed relative to the bearing size determine the permissible relubrication frequencies, provided an approved ball bearing grease is used.

Over-lubrication is equally hazardous as under-lubrication. If excess grease is maintained in the race-track under-pressure, excessive friction develops often resulting in the break-down of the grease, which in turn affect the life of the bearing considerably.

3.6 CONTROLLERS, STARTERS AND RHEOSTATS

The contact and insulating parts must be kept thoroughly free from dirt and moisture and there shall be firm metallic connection between fixed and removable contacts when they come together. The covers shall be removed periodically for inspection.

Fuse contacts and terminals must be examined periodically for cleanliness and tightness. When a fuse wire or strip has to be renewed, care must be taken that the new is of the correct metal and size.

TWO PART BEARING HOUSING

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3.7 SAFETY DEVICES

Remote tripping devices and limit switches which are provided for safety reasons but which may not be called upon to function under normal operating conditions, shall be checked for operation at regular intervals.

Interlocks designed to prevent unsafe operations shall be checked periodically by a deliberate attempt being made by a competent person to perform the operations which the interlocks are designed to prevent.

Where an emergency supply is provided, the source of supply and all ancillary apparatus shall be checked periodically.

3.8 CHECK CHART

A check chart should be kept for assistance in the maintenance of the motor. A recommended chart is given in Section 4. All reports and test results shall be recorded in a suitable log book.

4. AC MOTOR CHECK CHART

SI.No. Trouble Cause Remedy

01 Hot Bearings - Bent or sprung shaft. Straighten or replace shaft.

General. Excessive belt pull. Decrease belt tension.

Pulley too far away. Move pulley closer to bearing.

Pulley diameter too small. Use larger pulley.

Misalignment. Correct by realignment of drive.

02 Hot Bearings Insufficient grease. Maintain proper quantity of

ball or roller. grease in bearing.

Deterioration of grease or Remove old grease, wash

lubricant contaminated. bearings thoroughly in kerosene

and replace with new grease.

Excess lubricant Reduce quantity of grease.

Bearing should not be more than 1/2 filled.

Heat from hot motor or Protect bearing reducing motor

external source. temperature.

Overloaded bearing. Check alignment, side thrust and

end thrust.

Broken ball or Rough Replace bearing; first clean

races. housing thoroughly.

03. Oil leakage from Stream of overflow plug Remove re-cement threads

overflow plugs not tight. replace and tighten.

Cracked or broken Replace the plug.

overflow plug.

Plug cover not tight. Requires cork gasket or if screw

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05 Motor Wet Subject to dripping Wipe motor and dry by circulating heated air through motor.. Install drip or canopy type covers over motor protection.

Drenched condition. Motor should be covered to retain

heat and the rotor position shifted frequently.

Submerged in flood Dismantle and clean parts.

water. Bake windings in oven at

180°F (82°C) for 24 hours or until resistance to ground is sufficient.

06. Motor stalls Wrong application. Change type or size.

Consult manufacturer.

Overloaded motor. Reduce load.

Low motor voltage. See that nameplate voltage is

maintained.

Open circuit. Fuses blown, check overload

relay, starter and pushout.

Incorrect control Check control sequence.

resistance of wound Replace broken resistors.

rotor. Repair open circuits.

Mechanical locking in Dismantle and repair.

bearings or at air gap. Clean air gap if choked.

07. Motor connected No supply Voltage. Check Voltage on each phase.

but does not start One phase open voltage

too low.

04. Motor dirty Ventilation blocked end Clean motor will run 10° to 30°C

winding filled with fine cooler. Dust may be cement,

dust or lint. sawdust, rock dust , grain dust,

coal dust and the like.Dismantle entire motor and clean all windings and parts.

Rotor winding clogged. Clean and grind slip rings. Clean and

treat windings with good insulating varnish.

Bearing and brackets Dust and wash with cleaning solvent.

coated inside.

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If of slip-ring type, lower the starting resistance.

Rotor Defective. Look for broken rings.

Poor stator coil Remove end belts, locate

connection. with test lamp.

Mechanical locking in Dismantle and repair.

bearings or at air gap. Clean air gap if choked.

08. Motor runs and Power failure. Check for loose connections

then dies down. to line, to fuses and to control.

(see also SI.No.7).

Overload. Examine overload trips. See

that they are set correctly to approximately 150 percent full load current. See

that the dashpots are filled with correct quantity and grade of oil.

09 Motor does not Not applied properly. Consult supplier for proper

come upto speed. type.

Voltage too low at Use higher voltage on

motor terminals transformer terminals or

because of line drop. reduce load.

If wound rotor Correct secondary control.

improper control operation of

secondary resistance.

Starting load too high. Check load or motor which is

supposed to carry at start.

Check that all brushes Check secondary connections

are riding on rings. Leave no loads poorly

Motor may be over Reduce load or try to start

loaded. uncoupled from load.

Control gear defective. Examine each step of the control

gear for bad contact or open circuit. Make sure that brushes are making good contact with thering.

Starting torque of load If of squirrel cage type and

too high. with auto-transformer

starting change to a higher tap.

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10. Motor takes too Excess loading. Reduce load. If motor is

long to accelerate driving a heavy load or is

starting up a long line of shafting start more slowly allowing ample time for acceleration till it overcomes the difficulty.

Poor circuit. Check for high resistance.

Defective squirrel Replace with new rotor.

cage rotor.

Applied voltage too Get power company to

low. increase voltage tap.

11 Wrong rotation. Wrong sequence of Reverse connections of

phases. motor or at switchboard.

12. Motor overheats Check for overload. Reduce load.

while running

underload. Wrong blowers or Good ventilation is manifest

airshields, may be when a continuous stream

clogged with dirt and of air leaves the motor. If

prevent proper not,check with manufactuer

ventilation of motor.

Motor may have Check to make sure that all

one phase open leads are well connected

Grounded coil. Locate and repair.

Unbalanced terminal Check for faulty leads,

voltage. connections and transformers.

Shorted stator coil. Repair and then check

watt-meter reading.

Faulty connections. Indicate by high resistance.

SI.No. Trouble Cause Remedy

Broken rotor bars. Look for cracks near the rings. A

new rotor may be required as repairs are usually temporary.

Open primary circuit. Locate fault with testing device

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High voltage or Check terminals of motor

low voltage with voltmeter.

Rotor rubs stator If not poor machining,

bore replace worn bearings.

13. Motor vibrates: Motor misaligned. Realign.

after corrections

have been made. Weak foundations. Strengthen base.

Coupling out of Balance coupling.

balance.

Driven equipment Rebalance driven equipment.

unbalanced.

Defective ball or Replace bearings.

roller bearings.

Bearings not in line. Line up properly.

Balancing weights Rebalance rotor.

shifted.

Wound rotor coils Rebalance rotor.

replaced.

Polyphase motor Check for open circuit.

running single phase.

Excessive end play. Adjust bearing or add washer.

14. Unbalance line Unequal terminal volts. Check leads and connections.

current on

polyphase motors Single phase operation. Check for open contacts.

during normal Poor rotor contacts in Check control devices.

operation. control wound rotor

resistance.

Brushes not in proper See that brushes are

position in wound properly seated and shunts

rotor. in good conditions.

15. Scraping noise Fan rubbing air shield. Remove interference.

Fan striking insulation. Clean the fan.

Loose on bedplate. Tighten holding bolts.

16. Magnetic noise. Air gap not uniform. Check and correct bracket

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Loose bearings. Correct or renew.

Rotor unbalance. Rebalance.

NOTE : Certain amount of magnetic noise is inherent in some low speed designs and shouls not

cause alarm.

17. Motor sparking Motor may be Reduce the load.

at sliprings. overloaded.

Brushes may not be of Use brushes of the grade

correct quality and recommended.

may be sticking in the holders.

Brush pressure may be Adjust the brush pressure

too light or too much. correctly.

Sliprings may be tough, Clean the sliprings and

dirty or oily. maintain them smooth

glossy and free from oil and dirt.

Sliprings may be ridged Turn and grind the slipring

or out of truth. in a lathe to a smooth finish

5. MAINTENANCE SCHEDULE

The following Maintenance Schedule is suggested as a guide.

5.1 DAILY MAINTENANCE

a. Examine earth connections and motor leads.

b. Check motor windings for overheating. (Note that the permissible maximum temperature

is above that which can be comfortably felt by hand.)

c. Examine control equipment.

d. In the case of oil ring lubricated machines:

i. Examine bearings to see that oil rings are working.

ii. Note temperature of bearings;

iii. Add oil if necessary;

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5.2 WEEKLY MAINTENANCE

a. Check belt tension. In cases where this is excessive it should immediately be reduced

and in the case of sleeve bearing machines the air gap between rotor and stator should be checked.

b. Blow out windings of protected type motors, situated in dusty locations.

c. Examine starting equipment for burnt contacts where motor is started and stopped

frequently.

d. Examine oil in the case of oil ring lubricated bearings for contamination by dust, dirt,

etc. (This can be roughly ascertained on inspection by the colour of the oil).

5.3 MONTHLY MAINTENANCE

a. Overhaul Controllers.

b. Inspect and clean oil circuit breakers.

c. Renew oil in high speed bearings in damp and dusty locations.

d. Wipe brush holders and check bedding of brushes of slipring motors.

e. Check the condition of the grease.

5.4 HALF-YEARLY MAINTENANCE

a. Clean windings of motors subjected to corrosive or other element. Also bake and varnish

if necessary.

b. In the case of slip-ring motors check slip-rings for grooving on unusual wear.

c. Renew grease in ball and roller bearings.

d. Drain all oil bearings, wash with kerosene, flush with lubricating oil and refill with

clean oil.

5.5 ANNUAL MAINTENANCE

a. Check all high speed bearings and renew if necessary.

b. Blow out all windings of motors thoroughly with clean dry air. Make sure that the

pressure is not so high as to damage the insulation.

c. Clean and varnish dirty and oily windings.

d. Overhaul motors subject to severe operating conditions.

e. Renew switch and fuse contacts if badly pitted.

f. Renew oil in starters subjected to damp or corrosive elements.

g. Check insulation resistance to earth and between phases of motor windings, control

gear and wiring.

h. Check resistance of earth connections.

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5.6 RECORDS

Maintain a register (as per the specimen shown or enclosed) giving one or more pages for each machine and record therein all important inspections and maintenance works carried out from time to time. These records shall show past performance, normal insulation level, gap measurements, nature of repairs and time between previous repairs and other important information which would be of help for good performance and maintenance.

6. LIMITS OF TEMPERATURE RISE

Permissible maximum temperature rise for class ‘B’ insulation is 120°C

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DATA SHEET FOR SOOT BLOWER MOTORS

SI. No.

Description Long Retract Long Retract Wall Blower Wall Blower Rotary Blower 01. Application Long Retract

Rotary Long Retract Traverse Wall Blower Rotary Wall Blower Traverse Rotary Blower Motor 02. Frame Size 80 80 71 90 71

03. Flange Type IS 2223 Type C IS 2223 Type C IS 2223 Type C IS 2223 Type C IS 2223 Type C 04. Dimensions( Drg.No) 4--20-201-00303 4--20-201-00303 4--20-201-00303 4--20-201-00303 4--20-201-00303 05. Power in KW 0.45 0.37 0.05 0.56 0.09 06. Rated Voltage 415 415 415 415 415 07. No. of Phases & Frequency 3∅ 50 HZ 3∅ 50 HZ 3∅ 50 HZ 3∅ 50 HZ 3∅ 50 HZ 08. RPM(Approx imate) 1425 1365 1480 1425 1425

09. Duty 30 minutes 15 minutes Continous 30 minutes Continous 10. Ambient Temperature o C 65 65 65 65 65 11. Enclosure & Protection Totally enclosed non ventilated IP 55 protection Totally enclosed non ventilated IP 55 protection Totally enclosed non ventilated IP 55 protection Totally enclosed non ventilated IP 55 protection Totally enclosed non ventilated IP 55 protection 12. Class of Institution B B B B B 13. Voltage Variation % ± 10 ± 10 ± 10 ± 10 ± 10 14. Frequency Variation ± 5 ± 5 ± 5 ± 5 ± 5 15. Combined Voltage & Frequency Variation ± 10 ± 10 ± 10 ± 10 ± 10 16. Starting Torque in kgm. 1.1 0.46 0.245 1.09 0.29 17. Rated Torque 0.3775 0.264 0.0329 0.382 0.063

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DATA SHEET FOR SOOT BLOWER MOTORS(CONTD.)

SI.N o D escription Long R etract Long R etract W all B low er W all B low er R otary B low er 18. B reakdow n T orque in kgm . 1.06 0.485 0.265 1.12 0.29

19. Full load current in A m ps.(A pproxim at e) 1.26 0.86 0.44 1.36 0.64 20. N o. of leads 6 6 6 6 6 21. N am e Plate Stainless steel Stainless steel Stainless steel S tainless Stainless steel 22. Paint Epoxy grey

Epoxy grey Epoxy grey Epoxy grey Epoxy grey

23. C onduct size in the T erm inal B ox

M 20 x 1.5

M 20 x 1.5 M 20 x 1.5 M 20 x 1.5 M 20 x 1.5

24. Pow er Factor & R ated Load(A pproxim ate)

0.68 0.88 0.34 0.78 0.48 25. Efficiency in R ated Load (A pproxim ate) 71% 75% 45% 73.5% 44% 26. M axim um stalling T im e (A pproxim ate) H ot 20 sec cold 35 H ot 40 sec cold 75 H ot 35 sec cold 65 H ot 30 sec cold 55 H ot 35 sec cold 65 27. D irection of R otation R eversibl e

R eversible R eversible R eversible R eversible

28. O ther C onstruction al F eatures Shaft end w ith oil seal Shaft end w ith oil seal Shaft end w ith oil seal Shaft end w ith oil seal Shaft end w ith oil seal

29. W eight of M otor in kg. (A pproxim ate)

13.5 13.5 13.5 13.5 13.5

30. G D2 of M otor in kg.(A pproxim ate)

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INSTRUCTION MANUAL

DESCRIPTION, OPERATION AND

MAINTANENCE

SOOT BLOWER

GENERAL INSTRUCTIONS

PUB.NO.7501

Bharat Heavy Electricals Limited

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This general instruction, sets some guidelines in preventing puffs and furnace explosions during soot blowing and outlines the procedure for setting blowing pressures. A check list for operation and a recommended procedure for start-up are given for general care and correct start-up. The section on maintenance gives a detailed glimpse into the maintenance problem. The lubrication schedule helps the maintenance man to choose the correct lubricant and carry out the lubrication plans.

No Soot Blower system will operate satisfactorily if it is not properly installed, operated and maintained. It must be recognised that no amount of written instructions can replace intelligent thinking and reasoning on the part of the operators, especially when coping with unforeseen operating conditions. It is the operators’ responsibility to become thoroughly familiar not only with the equipment but also with all pertinent control equipment.

The instruction contained in this manual is only an outline of the correct procedures for operation and maintenance. The contents in this manual have been compiled and checked by experts in this field. Every possible care has been taken to ensure the contents are accurate. Suggestions for the improvement of the manual are welcome.

If you ever have any query about operation, maintenance or related problems, you are welcome to write to BHEL without obligation.

IMPORTANT INSTRUCTIONS DO’S

1. CARELESSNESS IN REPAIRING SOOT BLOWING EQUIPMENT CAN CAUSE

SERIOUS INJURIES. ACCIDENTS CAN BE PREVENTED BY TAKING SIMPLE PRECAUTIONS.

2. INCREASE FURNACE DRAFT BY APPROPRIATE ADJUSTMENTS OF THE

INDUCED DRAFT FAN TO TAKE CARE OF THE INCREASED FLUE GAS VOLUME DUE TO THE SOOT BLOWING OPERATION. THIS WOULD HELP TO PURGE COMBUSTIBLE GAS POCKETS.

3. AVOID SOOT BLOWING OPERATION WHEN THE REFRACTORY IS HOT

i.e.IMMEDIATELY AFTER STOPPING OR WHEN THE BOILER IS NOT IN SERVICE FOR SOME TIME.

4. ALL STEAM LEAKS SHOULD BE ATTENDED TO IMMEDIATELY.

5. AVOID EXCESS BLOWING PRESSURE.

6. MAIN MEDIUM VALVE SHOULD BE CLOSED IMMEDIATELY AFTER THE

COMPLETION OF THE SOOT BLOWING OPERATION.

7. FOR LUBRICATION, FOLLOW THE LUBRICATION INSTRUCTIONS

CAREFULLY.

8. RETRACT THE LANCE IMMEDIATELY IN THE EVENT OF FAILURE OF

POWER TO AVOID DAMAGE TO THE LANCE.

9. EVEN IF THE BOILER IN OPERATION DOES NOT REQUIRE SOOT

BLOWING, KEEP THEM OPERATING AT LEAST ONCE IN A WEEK. THIS WILL HELP IF COAL CHARACTERISTIC CHANGE AT A LATER DATE AND TO KEEP THE SOOT BLOWERS IN ORDER.

10. ALL THE PEEP HOLES SHOULD BE CLOSED AND LOCKED BEFORE WALL

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11. DURING OUTAGES, CHECK THE CLEARANCE BETWEEN THE EDGE OF THE LANCE TUBE AND THE SUPER HEATER, RE-HEATER TUBES. THERE SHOULD BE A MIN. GAP OF 100MM.

12. THE SOOT BLOWER LINE MUST BE STEAM BLOWN BEFORE THE

BLOWERS ARE PUT INTO OPERATION AT THE TIME OF COMMISSIONING.

DON’TS

1. DO NOT ATTEMPT REPAIRS BEYOND YOUR ABILITIES.

2. DO NOT OPERATE THE BLOWERS WITH WET STEAM.

3. DO NOT EXTEND THE LANCE OF LONG RETRACT WITHOUT BLOWING

MEDIUM WHEN BOILER IS ‘ON’.

4. DO NOT OVERTIGHTEN THE PACKING.

5. DO NOT HAND CRANK THE BLOWERS WHILE THE POWER OR BLOWING

MEDIUM IS ‘ON’.

1. GENERAL INSTRUCTIONS

1.1 Ordering Repair Parts

When ordering repair parts, always give the Name, Part No., Drg. No., as found on the parts lists and Model number as found on the brass name plate.

In the case of bearings and elements, swivel tubes or lances refer to Element Location Drawings and give the Drawing No. for the specific piece needed. Elements may vary for different locations.

If you have more than one boiler, give the type, size, rating and location of the boiler or boilers for which parts are needed, and the order number under which you purchased the Blowers for which parts are needed.

1.2 A Word of Caution

Carelessness in repairing a blowing equipment can cause serious injuries. Accidents can be prevented by taking simple precautions.

Always get permission and clearance from the proper authority before starting to repair any equipment.

Use proper lifting equipment for heavy equipment. Do not attempt repairs beyond your ability. Before repairing any equipment operated by steam or air, make sure all supply valves have been closed, tagged or locked and also the electrical connections are cut off. If steam or air supply lines must be energised for purpose of test, use extreme caution.

2. PREVENTING PUFFS AND FURNACE EXPLOSIONS DURING SOOT

BLOWING

Explosions, puffs, or blow backs that occur during or as a result of soot blowing operations should be reported to and discussed with the boiler manufacturer. It is impossible to establish a definite procedure to prevent these difficulties because of the variation of fuels and the design and operations of Steam Generating equipment. The start-up or operating engineers working in conjunction with design engineers or boiler manufacturing firms are best qualified to recommend procedures of operation on their particular equipment.

The following recommendations are presented for consideration when it is necessary to establish operational procedure to prevent these difficulties.

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(i) Cleaning Cycle

As a guide line we suggest a soot blowing cycle of once in a day to start with may be established. After watching the performance of the particular coal, oil or any other fuel, with reference to the deposit formation, the blowing cycle can be altered. It is essential to have a satisfactory cycle so that the heat recovery surfaces are kept free of deposits at the same time the tube surfaces are not damaged because of frequent blowing. The life of the soot blower parts will also proportionally decrease with increased frequency. The Boiler operating personnel can establish the optimum blowing cycle depending on the actual furnace conditions. It is impossible to predict the deposit formation since too many factors influence the same.

(ii) When possible, the boiler to be cleaned should be operating at or near the maximum

design load.

When soot blowers are operated at low boiler loads, clouds of soot may be blown into the gas stream to form explosive mixtures which may be ignited by the heat from furnace walls or by smoldering soot fires. Soot blower operation at low boiler load, with a resulting colder furnace may also result in some of the unburned combustibles escaping from the furnace and collecting in pockets in back passes.

Agitation and ignition of these gas pockets will cause puffs or explosions. All tube surfaces and gas passes, therefore, should be blown with the gas flow at or near maximum to purge the boiler of these possible explosion causes.

(iii) On oil or pulverised fuel fired boilers, soot blowers should be used with the burners

operating at the highest possible burning rate, maintaining even stable combustion. Soot blowing schedules should be established to take place during the heaviest load periods, or the burner firing rates should be increased during soot blowing. Burners should be checked during soot blowing for stability.

A high burning rate assures a lower oxygen content in flue gases which eliminate the difficulty as explained in (ii) above.

High and stable burning rates also prevent flames from being blown out by small puffs or agitation of the gas flow common while soot blowing.

(iv) Before operating soot blowers the furnace drafts should be increased by opening the

boiler outlet damper or by making the appropriate adjustments of the induced draft fan to take care of the increased flue gas volume due to the soot blowing operation. Increased furnace draft helps to purge combustible gas pockets explained in (ii) above. Increased furnace draft improves cleaning by moving soot particles through gas passes rather than re-depositing them on adjacent surfaces.

(v) Conditions may require the operation of soot blowing equipment with the burners

out of service as when cleaning prior to outages to facilitate inspections.This procedure is dangerous. If unavoidable, soot blowing operation should not proceed while the refractory is still hot and there is any possibility of soot fires still smoldering in the setting. Be sure the boiler is cold and inspect the setting for smoldering soot before blowing.

(vi) The normal sequence of soot blowing is to follow the gas flow through the boiler.

The first soot blower to be operated should be the nearest to the burners then each unit in turn along the gas passes to complete the cleaning cycle. This method thoroughly cleans the entire unit by moving along the passes rather than blowing them loose and redepositing them on adjacent surfaces. It may be desirable to reverse this procedure when soot deposits are unusually heavy to avoid plugging and puffs or explosions in the back passes.