Quick Sizing & Sourcing Snapshot

• Manufacturer:​ GE (General Electric)
• Part Number:​ IS200ECTBG2A
• System Platform:​ EX2100 / EX2100e Excitation Control (Mark VI/VIe)
• Hardware Type:​ Exciter Contact Terminal Board (ECTB – Simplex)
• Architectural Role:​ Provides passive field termination for 6 auxiliary contact inputs and 2 trip relays, interfacing a single M1 controller via the EMIO board in Simplex mode.
• Key Specifications:​ Simplex Mode Only, 70V DC​ Wetting, 2 Trip Relays​ (K1/K2), 4 Gen Purpose Relays.

System Architecture & Operational Principle

The is a passive terminal board mounted in the EX2100 Exciter Cabinet, designated for Simplex (Single Channel)​ architectures. It is the “G2” variant, which explicitly denotes Simplex Control, differentiating it from the “G1” (TMR/Redundant) versions.

Physically, it mounts to the cabinet frame. Upstream, it connects only to the M1 Controller​ via HSLA/EMIO​ links (typically using connectors like J405 on the board). Downstream, it handles the field wiring: it terminates six auxiliary contact inputs​ (powered/wetted by an isolated 70V DC​ supply from the M1 EPSM via plug J13M1) and hosts two heavy-duty Trip Relays​ (K1, K2, specifically K1M1/K2M1) for driving customer lockout circuits. It also provides four General Purpose Form-C relays​ (K1GP-K4GP) controlled by the EMIO for auxiliary sequencing (e.g., field flashing, cooling fans). Unlike G1 boards, this unit has no physical connections for M2 or C controllers; it is a straight 1:1 signal path for non-redundant exciters or auxiliary regulation loops.

Core Technical Specifications

• Operation Mode:​ Simplex Only​ (G2 Suffix denotes Simplex; G1 is Redundant)
• Signal Inputs:​ 6x Aux Contact Inputs​ (Wetted by 70V DC from J13M1)
• Monitored Inputs:​ 52G​ (Gen Breaker), 86G​ (Lockout) – 70V DC Wetting
• Trip Outputs:​ 2x Form-C Trip Relays​ (K1M1, K2M1), Driven by M1 EMIO
• General Relays:​ 4x Form-C (K1GP-K4GP), Customer Wired (Typ. 125V DC)
• Processor I/F:​ HSLA/EMIO Links (Primarily J405 for M1)
• Power Interface:​ J13M1​ (70V DC Input from M1 Power Supply ONLY)
• Terminals:​ TB1, TB2 (Barrier Strips for Field Wiring)
• Isolation:​ 500 V DC Channel-to-Earth (Relay Contacts)
• Indicators:​ Red LEDs​ per Input (Illuminates when contact wetted/closed)
• Mounting:​ Chassis Mount (Exciter Cabinet Frame)
• Environmental:​ 0°C to +60°C (Operational), Conformal Coated

Customer Value & Operational Benefits

Simplex Cost Efficiency

The “G2” (Simplex) design is built for single-unit applications (e.g., a standalone Hydro plant exciter or Balance-of-Plant auxiliaries). You avoid the CAPEX of redundant hardware (G1). This cuts installation costs by 40-60%​ on the I/O termination side while retaining full signal conditioning (70V wetting) and trip relay functionality.

Centralized Excitation I/O

Consolidates Aux Contacts (52G/86G), Trip Relays, and GP Relays​ onto one PCB. In retrofit jobs fitting an EX2100e into an old bay, this density eliminates separate “Relay Panels,” reducing panel footprint by 30%​ and shortening field cable runs.

High-Voltage Wetting Reliability

The 70V DC​ wetting (via J13M1) is superior to standard 24V for dry contacts. It burns through oxidation films on mechanical breaker aux contacts (52G), preventing “floating” inputs that cause nuisance “Breaker Open” trips​ in humid environments.

Field Engineer’s Notes (From the Trenches)

The “Gotcha” on the G2A is Mode Confusion. This board is Simplex Only. If you pull a failed G1 (Redundant) board from a TMR rack and slap a G2A in, the EMIO software will fault with “Architecture Mismatch” or “M2/C Not Responding” because the G2 lacks the physical traces/pins for M2/C (J408/J415).

70V DC Sourcing​ is critical. The 6 Aux Inputs (and 52G/86G) require 70V DC​ from the M1​ controller’s power supply via plug J13M1. If this 2-pin Micro-Fit is loose or the M1’s 70V fuse is blown, your “Gen Breaker Closed” inputs will read 0 (FALSE) even if the field contact is physically closed. Always check J13M1 seating​ first when aux inputs are unresponsive.

Torque TB1/TB2. The Trip Relays (K1M1/K2M1) often switch 125V DC to the customer’s lockout. A loose “Common” creates an intermittent open; the turbine runs fine until vibration bumps the wire, opening the lockout and tripping on “86G Actuated.” Use a 0.6 Nm driver.

Remember: This board provides Form-C Contacts​ for outputs; you must land your 125V DC Bus (+) on “Common,” and the Load Return on “NO.” If you backfeed 125V into the logic side, you’ll cook the EMIO interface.

Real-World Applications

• Hydro Plant Static Exciter (Simplex):​ The ECTBG2A terminates 52G (Breaker Status) and 86G (Lockout) using 70V DC wetting for a 50MW unit. It drives the Field Breaker Trip​ via K1M1. Since it’s a single-unit hydro plant, TMR is overkill; the G2 Simplex board handles AVR feedback loops reliably at 1/3 the cost of a G1 setup.
• Auxiliary Boiler Gen-Set:​ Managing “Excitation On” permissive for a gas-fired boiler’s 20MW generator. The 6 Aux Inputs read “Lube Pump Run” and “Breaker Charged” using 70V DC, interfacing to a single M1 controller.