IS200EGPAG1A GE EX2100, Exciter Gate Pulse Amplifier Board

Description:

The IS200EGPAG1A Gate Pulse Amplifier Board (EGPA) is used in the EX2100 Excitation Control. It takes the gate commands from the ESEL and controls the gate firing of up to six SCRs (Silicon Controlled Rectifiers) on the Power Bridge. It is also the interface for current conduction feedback, and bridge airflow and temperature monitoring.

The EGPA functional model with the major I/O is shown in the following figure. A nominal 125 V dc power source from the EPDM supplies an on-board dc/dc converter, that provides power for SCR gating over the full range of input supply voltage. LEDs provide visual indication of the status of the EGPA power supply, input gate commands from ESEL, EGPA outputs to the SCRs, currents into the bridge, line filter, cooling fan rotation, bridge temperature, alarms, or fault conditions.

Gate Command Inputs: The EGPA receives a total of six gate commands from the ESEL through a twisted
pair, multiconductor, shielded cable. Gate commands over the differential pair are optically coupled, filtered, ac coupled, and sent to the Gate Pulse Amplifier (GPA). There are six GPA, one for each SCR. EGPA provides galvanical isolation between individual SCR gates.
Sensor Inputs: Mechanical and electrical operating variables on the bridge are sensed and fed back
to the control as follows:
Conduction currents are sensed on all three phases of the bridge input. The EGPA acts as an interface between Hall Effect sensors located on the EXCS boards and the system control. The EGPA provides power to the EXCS, receiving a signal from EXCS indicating the status of current flow through each leg of the three-phase bridge input. These status signals are delivered to the EGPA at J9 ñ J10. The EGPA then conditions these signals and sends the bridge status out to the controller.
Bridge temperature is sensed through an RTD (thermistor) sensor input or temperature switch input. For new exciters, only the RTD input is used and jumpers on the EGPA disable the temperature switch inputs. If a bridge is being retrofitted with an EX2100 control, the two temperature switch inputs are used to interface with the temperature switches already mounted on the bridge. In this case, the RTD input is left open to disable it. Both the RTD and temperature switch inputs are connected to EGPA at J13.
Airflow sensors (fan rotation) detect loss of fan cooling in the bridge. Up to four fans can be connected to the EGPA through J12. The EGPA accepts either a pulsed or dry-contact, normally open sensor input from the fans. The mode of signal detection is configured through berg jumpers JP2 ñ JP4.
Line filter fuse failure is sensed at J14 on the EGPA. This sensor input accepts a single, normally closed, dry contact input.

Datasheet Link:

IS200EGPAG1A GE EX2100, Exciter Gate Pulse Amplifier Board PDF Datasheet