The IS200TTURH1BFD is a high-performance Primary Turbine Protection Input (TTUR) terminal board from GE, designed for use in Mark VI turbine control systems. Fully designated as IS200TTURH1BFD, this board works in conjunction with the VTUR processor board to provide critical turbine protection, speed sensing, generator synchronizing, and shaft monitoring functions. The IS200TTURH1BFD supports both simplex and TMR (Triple Modular Redundant) architectures, making it suitable for a wide range of gas and steam turbine applications.
The IS200TTURH1BFD is a member of the TTURH1B family, with the “BFD” suffix indicating a specific factory configuration (e.g., standard coating, component selection, or revision). This board is intended for Mark VI systems; for Mark VIe applications, the newer TTURH1C board is required. This product introduction provides a complete, SEO-optimized specification for the IS200TTURH1BFD. All references use the full product designation IS200TTURH1BFD to meet Google’s content uniqueness and keyword relevance standards.
Key Features of IS200TTURH1BFD
Turbine Speed Measurement: Up to 12 passive magnetic pickup (MPU) inputs for speed sensing from toothed wheels
Generator Synchronizing: Controls main breaker (52G) coil with three series relays (K25, K25P, K25A); provides generator and bus voltage inputs from potential transformers (PTs)
Shaft Monitoring: Shaft voltage and shaft current inputs for induced shaft voltage/current measurement
Flexible Architecture: Supports simplex (single VTUR) and TMR (three VTUR boards) configurations via jumpers JP1 and JP2
Diagnostic Feedback: Relay driver current monitoring, relay contact status, solenoid power loss detection, and ID device interrogation
ID Device: Read-only chips on connectors JR1, JS1, JT1, JR5, JS5, JT5 for board identification, serial number, revision, and plug location
Configurable Jumpers: JP1 and JP2 select Simplex or TMR mode for relay drivers K25 and K25P
High Sensitivity: MPU input sensitivity of 27 mV peak (detects speeds as low as 2 rpm)
Wide Pulse Rate Range: 2 Hz to 20 kHz with 0.05% accuracy
Robust Isolation: PT inputs are magnetically isolated with 1,500 V rms barrier; optical isolation for breaker circuits
Functional Description of IS200TTURH1BFD
The IS200TTURH1BFD is a terminal board that interfaces field devices (magnetic pickups, potential transformers, shaft sensors, breaker circuits) to the VTUR processor board. It provides signal conditioning, isolation, and relay outputs for primary turbine protection and automatic generator synchronizing.
Speed Measurement
The IS200TTURH1BFD accepts up to twelve passive magnetic pickup (MPU) signals. These pickups sense a toothed wheel on the turbine shaft to measure rotational speed. The board conditions the MPU signals and passes them to VTUR via connector JR5 (simplex) or JR5/JS5/JT5 (TMR). The input sensitivity of 27 mV peak allows detection of speeds as low as 2 rpm. The pulse rate range is 2 Hz to 20 kHz with 0.05% reading accuracy.
Optional TTL active speed pickups can be connected to TB3 (requires external power supply).
Generator and Bus Voltage Sensing
Two single-phase potential transformer (PT) inputs are provided: one for generator voltage and one for bus voltage. Each PT secondary delivers a nominal 115 V rms (75–130 V rms allowable for synchronizing). The IS200TTURH1BFD loads each PT with less than 3 VA. Each input is magnetically isolated with a 1,500 V rms barrier. These signals are used by VTUR for automatic synchronizing – comparing generator and bus voltage magnitude, phase, and frequency before issuing a close command to the main breaker (52G).
Main Breaker Control (Synchronizing)
The IS200TTURH1BFD contains three relays – K25, K25P, and K25A – whose normally open contacts are wired in series to supply 125 V dc power to the main breaker close coil. All three relays must be closed to energize the breaker. This provides a permissive chain, enhancing safety.
K25 and K25P are controlled by VTUR via programmable logic (synchronizing permissives).
K25A is controlled by the VPRO and TREG boards (emergency protection).
In TMR mode, control signals from the three VTURs are voted before activating K25 and K25P.
Each relay has two normally open contacts in series with the breaker coil for redundancy.
The external breaker circuit must include a normally closed auxiliary contact from the breaker to interrupt current after closing. The circuits are optically isolated and filtered with a 4 ms time constant. The external voltage range should be 20–140 V dc; for 250 V dc applications, interposing relays are required.
Shaft Voltage and Current Monitoring
The IS200TTURH1BFD monitors induced shaft voltage and shaft current to detect grounding or bearing problems. The shaft voltage signal is converted to a frequency (0–2,000 Hz) proportional to the induced voltage. A DC test applies 5 V dc to the external circuit to verify integrity, measuring DC current flow. An AC test (1 kHz, R module only) checks the VTUR shaft voltage circuit.
Shaft current is measured as AC amps via a shunt, with a peak-to-peak voltage up to 0.1 V.
Diagnostics and ID Device
VTUR runs continuous diagnostics on the IS200TTURH1BFD:
Relay driver feedback – if driver current does not match command, a fault is generated.
Relay contact status – normally closed contacts are monitored; mismatch with command creates a fault.
Loss of solenoid power (125 V dc) – creates a fault.
Slow sync check relay, slow auto sync relay, and locked K25 relay – each generates a fault.
Any unhealthy signal triggers the composite diagnostic alarm L3DIAG_VTUR.
Each connector (JR1, JS1, JT1, JR5, JS5, JT5) contains a read-only ID device with serial number, board type, revision, and plug location. If VTUR reads a mismatch, a hardware incompatibility fault is created.
Diagnostic signals can be individually latched and reset via the RESET_DIA signal once the condition clears.
Configuration – Jumpers JP1 and JP2
The IS200TTURH1BFD has two configurable jumpers (no switches). Set these according to your system architecture:
Jumper | Setting | Description |
JP1 | Simplex | Selects simplex mode for relay driver K25 |
JP1 | TMR | Selects TMR mode for relay driver K25 (three-way voting) |
JP2 | Simplex | Selects simplex mode for relay driver K25P |
JP2 | TMR | Selects TMR mode for relay driver K25P |
There are no other user-configurable components on the board.
Installation and Wiring for IS200TTURH1BFD
The IS200TTURH1BFD features two main I/O terminal blocks (TB1 and TB2), each with 24 terminals. Both blocks are removable for maintenance and secured with two screws. Terminals accept up to #12 AWG wires with 300 V insulation. A shield termination strip (connected to chassis ground) is located immediately to the left of each terminal block.
Typical wiring assignments:
TB1 / TB2 – Connect magnetic pickups (speed), shaft voltage/current sensors, potential transformers, and breaker relay circuits as per project drawings.
TB3 – Optional TTL active speed pickups (requires external power supply).
JR5 (simplex) or JR5/JS5/JT5 (TMR) – Connect to VTUR for speed signals via molded cables.
JR1 (simplex) or JR1/JS1/JT1 (TMR) – Connect to VTUR for all other signals (PT, shaft, breaker status, etc.).
For simplex systems, only one set of connectors (JR5 and JR1) is used. For TMR systems, all six connectors (JR5, JS5, JT5 and JR1, JS1, JT1) are used to fan out signals to three VTUR boards.
Refer to the figure “TUR Terminal Board Wiring” in GE documentation for detailed connection diagrams.
Replacement and Ordering Information for IS200TTURH1BFD
When replacing a IS200TTURH1BFD:
De-energize the turbine control system (follow lock-out/tag-out procedures).
Remove wires from TB1, TB2, and TB3 (note positions for reconnection).
Disconnect all cable connectors (JR1, JR5, and if TMR, JS1, JS5, JT1, JT5).
Remove the board by unscrewing mounting screws.
Install the new IS200TTURH1BFD.
Set jumpers JP1 and JP2 to match the original board (Simplex or TMR).
Reconnect all wires and cables.
Apply power and verify that VTUR recognizes the ID devices and no diagnostic alarms are present.
To order the IS200TTURH1BFD, provide:
Full part number: IS200TTURH1BFD
Turbine controller model (Mark VI)
System serial number (if available)
Contact GE or an authorized distributor for pricing and availability.
Why Choose IS200TTURH1BFD for Your Turbine Control?
The IS200TTURH1BFD is a proven, reliable interface board for primary turbine protection and synchronizing in GE Mark VI systems. Its high-speed magnetic pickup sensitivity (2 rpm detection), isolated PT inputs, and TMR capability make it suitable for critical power generation applications. Integrated diagnostics, ID device verification, and configurable relay voting enhance system safety and maintainability.
Key advantages include:
High accuracy speed measurement (0.05%)
Wide input range (2 Hz to 20 kHz)
Flexible architecture – simplex or TMR with jumper selection
Comprehensive diagnostics – relay feedback, power loss, ID check
Isolated inputs – 1,500 V rms for PTs, optical isolation for breaker circuits
Shaft monitoring – voltage and current for bearing/ground fault detection
