Synchronised with Other Sources

See (10.7), the basic principles apply, but in most situations there will not be other generators to synchronise with, only the normal incoming feeder from a transformer. Engine driven generators will normally be single units intended for island operation. They are normally installed for standby, emergency, essential or black-start duties.

However, at least the engines need to be started regularly so that they can be relied upon when needed. Consequently, they should be provided with synchronising facilities, which shall be manual or automatic depending upon the duty of the generator. The generator shall therefore be tested for manual and auto-synchronising to the supply.

12.0

HV Motors

Most of the HV motors installed in QGPC plants will be induction motors of the caged rotor type, designed for direct-on-line (DOL) starting. Occasionally, variable speed motors (VSDS) will be required and these will normally be the cage rotor type, synchronous motors may be used for very large drives e.g. 5000kW and above. For the purposes of installation, testing and commissioning the approach should be the same for both induction and synchronous motors. The synchronous motors will require some extra testing and commissioning of their rotors and rotor controllers. These would be special application motors and so they would normally be commissioned under the supervision of the motor or driven machine site representative, and the rotor equipment would be included.

The minimum rating of HV motors shall normally be for industrial and hazardous area applications. HV motors shall be the manufacturer’s standard design to duty type S1, in BS 4999 Part 112, Design D.

In general HV motors shall be installed, tested and commissioned using similar procedures that apply to HV generators of ratings up to approximately 10MW. In most cases the motor

should be a part of a skid mounted package and supplied with the purchase order of the complete package.

Before any checking or testing is carried out the CONTRACTOR shall carefully study all the manufacturer’s documents, especially those relating to pre-commissioning and testing.

The CONTRACTOR shall plan the work to be done and in so doing liaise closely with the driven machine manufacturer, the motor manufacturer, and the site representative of QGPC. QGPC shall approve the plan and scope of work.

12.1 Division of Discipline Responsibilities

See (10.1), most of the functions will be the same, but less extensive.

12.2 Preliminary Checks

See (10.2), replace ′generator′ with ′motor′

12.3 Installation

See (10.3), replace ′generator′ with ′motor′.

Note 12.3.a: - Many motor applications do not have dedicated fire, gas and smoke systems, but they may be located in areas which have overall systems.

12.4 Post-Installation un-Energised Testing

See (10.4), (10.4.1) and (10.4.3) replace ′generator′ with ′motor′.

Note 12.4.a: - Some applications may have HV motors fed from HV switchboards which have rated voltages above 11kV e.g. 33kV . In these situations the motor will be provided with a unit transformer of comparable kVA rating, therefore the approach described in (10.4.2) shall apply.

12.5 Post-Installation Energised Testing

See (10.5), replace ′generator′ with ′motor′. 12.5.1 Shaft coupling

Note 12.5.1.a: - The last function to perform shall be to disconnect the shaft coupling without disturbing the motor on its footings, if this is possible. Refer to the driven machine MI to find out whether or not the machine’s shaft can be run in either direction, and if so for how long a period. Some driven machines must not be run in a reverse direction under any circumstances, because damage can be done to e.g. thrust bearings, dry-gas seals, gearboxes.

Note 12.5.1.b: - If Note 12.5.1.a confirms that reverse rotation is not permitted, then the motor shall be moved along its mountings to allow the coupling to be ‘split’. The feet of the motor shall be temporarily clamped to the base

frame so that the motor frame does not move when its shaft is allowed to rotate.

Note 12.5.1.c: - Where motors have insulated bearings it is recommended that their shaft induced voltage be measured at full speed.

12.6 Commissioning Energised Testing

See (10.6), replace ′generator′ with ′motor′. 12.6.1 High voltage testing

See (10.6.1), replace ′generator′ with ′motor′. 12.6.2 Testing control systems of synchronous motors

In the case of synchronous motors additional testing shall be required for their rotor excitation system. The excitation of the rotor will be regulated by a controller which will have a purpose specific to the motor and the nature of the driven machine. It may be designed to regulate : -

• Supply power factor between limits.

• Shaft torque to prevent pull-out from synchronism.

• A function of the driven machine characteristics.

Check that any control settings e.g. gain, damping, upper limits, have been fixed in accordance with the motor MI.

During the final commissioning tests when the motor drives its machine the functions of the excitation controller shall be carefully checked.

Readings of instruments at the UCP, CCR and the switchboard shall be taken and recorded on test data sheets. Adjustments shall be made to obtain the best performance from the motor driven machine.

13.0

LV Motors

The maximum rating of LV motors shall normally be 250kW for industrial and hazardous area applications. For special cases the maximum rating may be increased subject to carefull calculation of volt-drop on starting and accelerating torque during the run-up period. LV motors shall be the manufacturer’s standard design to duty type S1, in [BS 4999 Part 112], Design D for ratings above 40 kW and Design N for ratings lower than 40 kW.

No modifications shall be made to hazardous area motors and their terminal boxes by the driven machine supplier or the site contractor. If upon inspection it is found that post-factory modifications have been made then the motor shall be rejected, replaced and the replacement delivered to site at no cost to QGPC.

Hazardous area motors shall have their cables terminated through Ex(d) glands. The entry dimensions and threads in the terminal boxes shall be made by the manufacturer in his factory, and should have been inspected during the factory acceptance tests, if such tests were required by QGPC. The terminal boxes should be of the type of protection Ex ‘e’ for motors that will be installed in a Zone 1 area. See [ES.2.14.0030 and 0035 for motors].

Hazardous area certification, type test certificates and routine test reports shall be made available to QGPC by the manufacturer, as part of the purchase order documentation. These certificates shall be included in the documentation from the CONTRACTOR. The QGPC certification requirements are described in [ES.2.03.0001, section 7.5].

Electrical discipline engineers shall liaise with the mechanical discipline engineers on site who are responsible for the driven machine unit or package. Testing and commissioning of the complete unit or package shall be a planned and coordinated activity.

13.1 Preliminary Checks

The following guidance shall apply to minor motor-machine units of a few kilowatts through to packaged and skid mounted assemblies of several hundred kilowatts.

Check the name plate details of the motor for voltage, currents, frequency, winding connections, tag numbers, ratings, etc, against the project documents.

Check the name plate details of the hazardous area details, i.e. type of protection (‘n’, ‘e’, ‘d’), gas group (IIB, IIC), temperature class (T3, T4, etc).

Check that any auxiliaries have been installed e.g. winding temperature detectors, anti- condensation heaters, and that their cables have been terminated.

Remove all terminal box covers. Store them in a clean place, and ensure the gaskets if used are not damaged.

13.2 Installation

The motor frame shall be bonded to its base frame at one point which shall preferably be near the main terminal box. The point on the base frame shall be a welded boss, capable of accepting a suitable diameter bolt for the bonding cable.

All motors, power terminal boxes, and other electrical items which are bolted to the base frame or extensions to it shall be bonded to the same structure using green/yellow insulated stranded cable. [ES.2.03.0001] gives guidance on the design of earthing and bonding.

13.3 Post-Installation un-Energised Testing

Test the earth continuity at the joints of the main bonding connections and record the results. Motors having large ratings or long route lengths of cables may require several cable cores connected to each phase terminal in the main terminal box. The motor may be provided with two main terminal boxes, one for the phase terminals and the second smaller one for the internal auxiliaries e.g. condensation heater, winding temperature detectors.

13.4 Post-Installation Energised Testing

Arrange for suitable supplies for test equipment.

Check the phase sequence connections of the motor complete with its stator cables, and that these correspond with those at the associated main circuit breaker and switchboard busbar

system. Check that the sequence is correct i.e. L1, L2, L3 is preferred. Table 10.5.A may be used in the absence of other design information.

Use low voltage test equipment to test for the following functions: -

• Continuity of power connections of large motors.

• Earth loop impedance, if not covered previously under cable or auxiliary Equipment tests.

• Insulation resistance of the windings.

• Insulation resistance of embedded temperature detectors in stator windings and condensation heaters.

13.5 Commissioning Energised Testing

Arrange for suitable permanent low voltage supplies to be available so that the windings may be energised in their normal state for a prolonged duration, i.e. longer than for only the testing period.

Refer to MI for all testing to be carried out for commissioning the motor as a complete unit with its driven machine.

Check that all cables and auxiliary systems have been terminated, tested and put into normal service.

Check that all cable armouring has been earthed , and have been tested for earth loop resistance.

13.5.1 Shaft coupling

Note 13.5.1.a: - The last function to perform should be to disconnect the shaft coupling without disturbing the motor on its footings, if this is possible. Refer to the driven machine MI to find out whether or not the machine’s shaft can be run in either direction, and if so for how long a period. Some driven machines must not be run in a reverse direction under any circumstances, because damage can be done to e.g. thrust bearings, seals, gearboxes.

Note 13.5.1.b: - If Note 13.5.1.a confirms that reverse rotation is not permitted, then the motor shall be moved along its mountings to allow the coupling to be

′split′. The feet of the motor shall be temporarily clamped to the base frame so that the motor frame does not move when its shaft is allowed to rotate.

13.5.2 Running lightly loaded

LV motors usually have rolling element bearings. In order to verify that these bearings have not been damaged in transit to site, or by ingress of water, the motor shall be run uncoupled or unloaded for a minimum period of 2 hours. During which time the bearing caps shall be felt or measured for surface temperature, and ″listened to″ for loud or irregular noise patterns. During or at the end of this test the starting time and current shall be checked against the motor data sheet.