IS200EHPAG1B

IS200EHPAG1B is an exciter gate pulse amplifier board developed by GE. It is a part of the EX2100 Excitation system. The Gate Pulse Amplifier Board is used in 100 mm EX2100 Excitation Control. It receives ESEL gate commands and controls the gate firing of up to six SCRs (Silicon Controlled Rectifiers) on the Power Bridge. It also serves as an interface for current conduction feedback as well as bridge airflow and temperature monitoring. The EHPA board connects the power bridge to the control. EHPA receives gate commands from the controller's ESEL board and generates gate firing pulses for six SCRs (Silicon Controlled Rectifiers). It also serves as an interface for current conduction feedback as well as bridge airflow and temperature monitoring.

Features

• An RTD is used on a new exciter to monitor temperature and generate alarms. Additional switches activated by fan rotation track the flow of cooling air across the bridge. The exciter may accept feedback from two thermal switches mounted on the SCR heatsink assemblies in an exciter controls only retrofit. At the alarm level, one thermal switch opens, and the other at the trip level.
• These switches are connected to the EGPA board and may need to be retrofitted into the existing bridge. A bridge overtemperature alarm is generated if either switch is opened. A fault and a trip are generated if both switches are open.
• EHPA boards do not have this feature. A nominal 125 V dc power source from the EPDM powers an on-board dc/dc converter, which provides power for SCR gating across the entire input supply voltage range. LEDs display the status of the EHPA power supply, ESEL input gate commands, EHPA outputs to the SCRs, bridge currents, line filter, cooling fan rotation, bridge temperature, alarms, or fault conditions.

Board Replacement Procedure

1. Ensure that the excitation system in which the board is located is de-energized.
2. Open the Power Conversion Cabinet door and test any electrical circuits before touching them to ensure that the power has been turned off.
3. Ensure that all EHPA LEDs are turned off.
4. To facilitate reconnection, ensure that all EHPA cables are labeled with the correct connector name (as marked on the board).
5. Remove all cables from the EHPA board with care.
6. Take the EHPA board out of its mounting.
7. Examine the replacement EHPA board to ensure that all jumpers are in the correct positions (the same as on the original board).
8. Place the replacement EHPA board back into its mounting.
9. Reconnect and tighten all of the cables removed in step 4.

Handling Precautions

• Keep circuit boards in antistatic bags or boxes.
• When handling boards or board components, use a grounding strap.