The GE IS200ESELH2AAA Exciter Selector Board functions as the redundancy management core in 

GE’s EX2100 excitation control system, responsible for orchestrating seamless between primary, 

secondary, and backup excitation control channels to maintain uninterrupted generator excitation. Its 

primary role is to monitor the health and performance of redundant regulator modules (e.g., 

IS200DSPX) by continuously evaluating key parameters—including output signal consistency, 

communication status via the EISB bus, and power supply integrity. When anomalies are detected in 

the active channel (such as loss of field current regulation or communication failure), the board 

automatically triggers a failover to the standby channel within 8ms, a speed critical for preventing 

generator terminal voltage fluctuations or trips. It also supports manual via front-panel switches or 

remote commands from the EX2100 HMI, enabling planned maintenance without system downtime. 

Additionally, the board aggregates and transmits real-time status data (e.g., active channel identifier, 

fault codes,  history) to the system controller, with front-panel LEDs providing at-a-glance visibility of 

operational states (active/standby/fault). Built with rugged components and IPC-CC-830B Class 3 

conformal coating, it withstands harsh industrial environments (vibration, temperature extremes, and 

electromagnetic interference) and integrates seamlessly into EX2100 racks, supporting hot-swap 

capabilities to maximize system availability.

Key Functional Features

Safety-Critical Shutdown Logic: Executes predefined shutdown sequences (e.g., de-energizing the excitation field) within milliseconds of detecting faults—prevents turbine damage from conditions like overspeeding (caused by loss of excitation) or insulation breakdown (from overexcitation).

Configurable Thresholds: Via GE ToolboxST software, users can adjust fault thresholds (e.g., maximum excitation voltage, minimum excitation current) and time delays to match specific turbomachinery requirements (e.g., gas turbine vs. steam turbine excitation systems).

Comprehensive Diagnostics:

Self-diagnostics: Monitors module power, internal logic circuits, and input/output connections—alerts the Mark VIe/VI system to module faults (e.g., power loss, broken input wires).

Fault logging: Records shutdown events (timestamp, fault type, pre-fault parameters) for post-incident analysis, aiding in maintenance and root-cause identification.

Redundancy Support: Can be configured in 1+1 redundant pairs for high-availability applications (e.g., critical power plants). Redundant modules synchronize data to ensure seamless failover if the primary module malfunctions.

GE Ecosystem Integration: Tightly integrated with GE’s Mark VIe/VI human-machine interface (HMI) and PlantPAx DCS—enables real-time monitoring of excitation system status, shutdown triggers, and module health via a centralized operator station.

Technical Specifications

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