Electrical Type
SECTION 6: T200 FUNCTIONAL OVERVIEW
6.4 Power Interface Section
6.4.1 T200 Model Types and High Power Interface
Two basic types of the T200 are
available:-1. The T200-X10 models accept a.c. mains inputs with a nominal voltage level from 120Va.c. to 230Va.c. (where X stands for a digit between 3 and 5). The T200-610/710 models accept a.c. mains input with a nominal voltage level of 230Va.c.. The T200-310, T200-410, T200-510, T200-610 and T200-710 models include integrated high voltage power supply, control and motor power sections.
2. The T200-X00 models accept d.c. inputs with a voltage level from 30Vd.c. to 400Vd.c. (where X stands for a digit between 3 and 5). The T200-300, T200-400 and T200-500 consist of control and motor power sections only.
The exact type of T200 which the user will require will depend upon the type of
application:-§
For single axis applications, a Servo-drive with integrated high power supply must be used (T200-X10).§
For multiple- axis applications, a unit with integral PSU supplies D.C. Bus high power to units without an integral PSU (T200-X10 with several T200-X00 units).6.4.2 High Power Section Description
The high power supply section has the following features:
§
Single or Three Phase a.c Operation.§
Direct Off-Line 120Vr.m.s. to 230 V r.m.s Operation.§
Soft Start (a.c. Inrush Current Limiting).§
Input MOV Transient Protection.§
Internal 40W Regeneration capability, protected by an electronic circuit breaker (T200-310/410/510 models only).§
Fast Bus Discharge.§
Power Ready Relay.§
Provision for External Regeneration Resistor.§
Integral Shunt Regulator.§
Integral Heat Sink and Cooling Fans.These features are described in the next sections.
WARNING - The high power section contains large capacitors that maintain high voltage on the d.c.+ to d.c.- terminals for several minutes after input power is removed, if the regeneration circuit is not operating normally. Wait at least 5 minutes after power shutdown for capacitors to discharge. Then use a voltmeter to check for safe voltage from the d.c.+ terminal to the d.c.- terminal before contacting terminals or commencing any service or maintenance activities to ensure no lethal voltages are present. Failure to follow this procedure may result in serious personal injury or death.
Figure 6.7:- T200-X10 in Single-Axis Application
Figure 6.8:- T200-X10 in Multi-Axis Application
6.4.2.1 High Power Circuit Description
The high power supply section may be divided into functional blocks:
• High voltage rectification and filtering
• Soft-start of a.c. mains power-on
• Low voltage control power supply
• Regeneration circuit
• Monitoring and fault logic circuits
a) High Voltage Rectification and Filtering
The a.c. mains input is rectified by a three phase diode bridge and filtered by a bank of electrolytic capacitors to generate a nominal 325 V d.c. supply. This high power 325 V d.c. supply is unregulated and will vary in direct proportion with the a.c. mains input voltage magnitude.
A.C. Mains Type D.C. Bus Voltage Level
230V Single and Three Phase Mains 325Vd.c.
120Va.c. Mains 170Vd.c.
Table 6.1:- Magnitude of the D.C. Bus b) Soft Start
Soft start is used to limit the inrush current to the d.c. bus capacitor bank on application of a.c. mains power. This is intended to prevent nuisance tripping of circuit breakers or blowing of line fuses on power-up.
The soft start relay will close when the monitoring circuit senses that the high-voltage d.c. bus has charged up to close to the value of the rectified a.c. mains.
Section 3.10 provides details on how the soft-start circuitry functions when T200-X00's are connected to a T200-X10 via the D.C. Bus.
c) Low Voltage Control Power Supply
Control power for the logic circuits is generated by a DC/DC converter, which provides control-circuitry power that is isolated from the mains input. This control voltage also powers the cooling fans. The DC/DC can generate control power from three sources
1. D.C. Bus if it is greater than 250Vd.c.
2. 24Vd.c. external supply which is provided by the user specifically for control-backup power.
3. Isolated 120Va.c. external supply which is provided by the user specifically for control-backup power.
The T200 will always generate power internally from the D.C. Bus (if its voltage is greater than 250Vd.c.) even though the 24Vd.c. and/or the 120Va.c. control-backup supplies are present.
d) Regeneration Circuit
Rapid motor deceleration or an overhauling load creates a situation in which energy is returned back into the D.C. Bus.
The Regeneration energy will charge up the power supply bus capacitors, causing their voltage to increase. To prevent capacitor overvoltage, a shunt regulator circuit senses when the bus voltage exceeds the Regeneration cut-in voltage and switches a Regeneration resistor across the D.C.Bus, (via a Regeneration transistor) to dissipate the Regeneration
energy. The frequency at which the Regeneration circuit operates is dependent upon the magnitude of the Regeneration energy.
The internal Regeneration resistor is protected by an internal electronic circuit breaker which disables Regeneration when the internal resistor’s rating is exceeded.
If the Regeneration energy exceeds the capacity of the internal Regeneration circuit, a higher capacity external Regeneration resistor must be used. Section 3.13 described how to install such a resistor. If the external resistor’s rating is exceeded, the T200 Servo-drive reports a warning to the user, via both the 7-segment display (U6 or E6 warning) and the activation of the THRM_LIM digital output.
A suitably rated fuse to short-circuit protect the external Regeneration resistor is fitted internally in the T200-310, 410 and 510 servo-drive. The fuse is sized to protect the external resistor option available for that particular T200 model, as described in Section 3.13. The user should not change this fuse. If this fuse is blown, then the T200 must be returned to Moog for repair. For T200-610 and T200-710 servo-drives, the fuse must be provided externally.
For further information regarding the implemented regen resistor protection scheme see section 6.8 - Self Protection.
e) Monitoring and Fault Logic
When a.c. mains power is first applied to the PSU, the inrush charging current is limited. When the T200 senses that the D.C. Bus has been charged up, the Soft Start Relay energises to switch the power supply into its normal configuration.
Note that a blown Regeneration fuse or an open internal Regeneration resistor will prevent the power supply from starting up, and generate a fault indication ('F3' on the 7-segment display) .
When a.c. power is removed, a fast discharge of the D.C. Bus occurs discharging internal high voltages.
A thermistor on the high power section heatsink is used to generate a PSU Over-temperature fault if the temperature of the a.c. mains rectification circuitry exceeds its rating.
A fault condition is caused by any of the following:
• Regeneration Fuse Blown. The internal regeneration resistor fuse has been blown. Fault F3 is displayed on the 7-segment display. The unit must be returned to Moog for repair.
• PSU Thermal Fault:- The Bridge Rectification Circuitry Heatsink temperature is excessive. Fault F4 is displayed on the 7-segment dispay.
• Bus Overvoltage:- The D.C. Bus voltage exceeds 410Vd.c. The fault code F2 is shown on the 7-segment dispay.
Any faults detected are relayed to the control electronics where the appropriate diagnostic message will be displayed on the seven segment display and appropriate action taken. T200 operation under fault conditions is described in Section 6.7.
High Power Section System Sequencing
High power sequencing is described in Section 3.10.
WARNING. The fast bus discharge circuitry may become damaged during operation, or may not be operational if the F3 fault is active. The user should still wait for 5 minutes after all power has been removed to begin service operations on the T200.