GE IS200EPSMG2A Exciter Power Supply Module

GE IS200EPSMG2A Exciter Power Supply Module

Functional Description

The EPSM is used in both the thyristor and regulator control systems. EPSM Group 1 modules (EPSMG1) are

used in the thyristor system and EPSM Group 2 modules (EPSMG2) are used in the regulator control.

EPSMG2 includes an Exciter Regulator Power Supply Daughterboard (EPSD).

The EPSM comprises two major sections, a buck-regulator and a push-pull inverter. The buck-regulator

converts the input voltage to a 50 V dc intermediate voltage. This intermediate voltage is then applied to a

push-pull inverter to create the required multiple output voltages. The transformer used in the push-pull

inverter provides high-voltage isolation between the input voltage source and the output supplied to the

control system. 

In regulator control, EPSM converts the dc link bus voltage into the voltages required for the EX2100

regulator control. In simplex systems, one EPSMG2 is mounted in the Exciter Regulator Backplane (ERBP). In

redundant systems, one EPSMG2 is mounted in ERBP (M1) and a second EPSMG2 is mounted in the Exciter

Regulator Redundant Backplane (ERRB, M2/C). The EPSD modifies the power input path to allow EPSM to

accept higher voltages. It also provides a fuse between the regulator power source (dc link) and the buck-

regulator.

The EPSMG2 supplies +5 V dc, ±15 V dc, and +24 V dc to the ERBP and ERRB. Power is also supplied to

external modules as follows: 

• ±24 V dc (P24B/N24B) to power fans, relays, and the dc feedback board 

• Isolated +70 V dc (P70) for contact-wetting on the terminal board, dynamic discharge board, and

redundant relay board

• Isolated 20 V ac (AC17) to power the insulated gate bipolar transistor (IGBT) gate and dynamic discharge

board 

• ±55 V dc (P55/N55) to the ground detector circuits on the options board

Technical Specifications