IC3600SHPB1E1C - Single Shaft Auxiliary Board

SPECIFICATIONS

Part No: IC3600SHPB1E1C
Manufacturer: General Electric
Function: Single Shaft Auxiliary Card
Series: Mark I and II
Repair: 3-7 Day
Availability: In Stock
Country of Manufacturer: United States (USA)

Functional Description

IC3600SHPB1E1C is a Single Shaft Auxiliary Card developed by GE. It is a part of Mark I and II control system. This card plays a role in the speed control loop, ensuring accurate and reliable speed signal processing, sensor fault detection, and simulation of speed signals for testing and diagnostic purposes.

Speed Signal Cross-Coupling Network

At the core of the card is a redundant signal processing network that allows speed feedback from two magnetic pick-up (MPU) sensors to be combined in such a way that:

• If one sensor fails (either due to an open or short circuit), the system continues to receive an accurate speed signal.
• The outputs from both sensors (RSZ and SZA) are tied together, enabling a robust, fault-tolerant speed feedback mechanism.
• This cross-coupling enhances system reliability, especially in critical turbine operations where uninterrupted speed measurement is essential.

Zero Speed Detection

• The card receives input pulses via the MPR terminal, which represent the rotational speed of the turbine shaft.
• These pulses are processed to produce output pulses on RSR, which are used to determine whether the turbine is at zero speed.
• Zero-speed detection is essential during startup, shutdown, or protective shutdown operations where confirmation of rotor standstill is required before proceeding.

Sensor Fault Detection (Open/Short Monitoring)

To ensure signal integrity and provide early warning of wiring or sensor issues, the SHPB card includes fault detection circuits:

• A short or open circuit between MPZ and ACOM (analog common) causes the FLTZ logic output to go high (1) and illuminates the FLTZ indicator light, alerting operators to a fault in that signal line.
• Similarly, a short or open circuit between MPR and ACOM results in a high (1) on the FLTR output, activating the FLTR indicator light.
• These visual and logical fault signals help maintenance teams quickly isolate and resolve sensor wiring problems.

Under-Speed Test Circuit

The card also incorporates an under-speed simulation circuit, which is used for testing and calibration:

• This circuit is activated by a limit switch mounted on the RH1 potentiometer.
• When engaged, it delivers a positive adjustable current through output pin SPD.
• This current simulates a speed feedback signal by feeding into the speed control summing junction, effectively reducing VCE (control voltage) and allowing test conditions to be replicated without actual shaft movement.
• The US output goes high (1) when the under-speed test circuit is active. 

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FREQUENTLY ASKED QUESTIONS

What is IC3600SHPB1E1C?
It is a Single Shaft Auxiliary Card developed by GE.

How does the card maintain feedback signal reliability?
It uses a cross-coupling network to combine signals from two magnetic pick-up heads. If one sensor fails, the card still maintains a valid speed feedback output using the other, ensuring continuous monitoring.

What is the function of RSR?
RSR outputs pulses that reflect zero-speed conditions based on the MPR input signal. This is used to determine if the turbine has completely stopped.

What happens if there is a short or open circuit in the sensor wiring?
A short/open between MPZ and ACOM triggers a high signal on FLTZ and lights the FLTZ indicator. A short/open between MPR and ACOM triggers a high signal on FLTR and lights the FLTR indicator.