GE V7668A-1310B0 / 350-9310007668-131000 B

Overview
The GE V7668A-1310B0, also identified by the part number 350-9310007668-131000 B, is a critical electronic interface module designed to command and control high-performance hydraulic servo valves. This driver card acts as the intelligent translator between a turbine or compressor control system’s low-power command signals and the high-power electrical currents required to precisely position servo valve pilot stages. It is an essential component within GE’s Mark VI, Mark VIe, or similar Speedtronic™ turbine control systems, enabling accurate fuel, steam, or gas flow modulation for superior process control and equipment protection.

Physical and Electrical Structure
This module is a printed circuit board assembly (PCBA) typically housed in a protective metal or plastic carrier designed for VME or other standard industrial bus backplanes. Its architecture integrates several key functional blocks: a digital signal processor (DSP) or microprocessor for command processing and diagnostics, high-current output amplifiers to drive the servo valve torque motor coils, feedback monitoring circuits, and robust power supply conditioning. Front-edge connectors interface with the system backplane for communication and power, while rear-facing connectors or terminal blocks provide the high-current output leads to the servo valve and receive valve position transducer (LVDT/RVDT) feedback signals.

Installation Guidelines and Replacement Procedure
Pre-Installation: Ensure the control system is properly shut down and locked out/tagged out (LOTO). Verify the replacement card’s part number matches exactly. Document all existing jumper settings, switch positions, and connector locations on the old card.
Installation: Wearing an anti-static wrist strap, carefully align the new card with the guide rails in its designated slot. Apply firm, even pressure to seat it fully into the backplane connectors. Secure the card using the provided screws or retainers. Reconnect all output and feedback wiring to the correct terminals, double-checking against the system schematic.
Post-Installation: Before powering the system, verify all connections. Upon power-up, the system will typically run diagnostics. Use the engineering workstation software to verify card recognition, calibrate the servo loop if necessary, and perform a low-amplitude function test of the associated valve.

Key Functional Specifications

• Command Input: Accepts a demand signal from the main controller, typically ±10 V DC or 4-20 mA, representing the desired valve position.

• Output Drive: Supplies a proportional, high-current (typically up to several hundred mA) signal to the servo valve torque motor. The output is often a differential current (±mA) for improved noise immunity.

• Feedback Interface: Accepts signals from the valve’s built-in LVDT/RVDT (e.g., AC excitation and AC return signals) to monitor actual spool position and close the control loop.

• Loop Closure: Functions as a sophisticated servo amplifier, comparing command signal to valve position feedback and using PID or other control algorithms to drive the valve to the precise commanded position.

• Diagnostic Capabilities: Monitors for faults such as coil open/short circuit, LVDT failure, excessive position error, and internal card health, reporting these to the main control system.

• Communication: Interfaces with the turbine controller via the system backplane (e.g., VME bus) for command, data, and status exchange.

  
  

Primary Industrial Applications
This servo driver is pivotal in applications requiring precise and rapid hydraulic actuation:

• Gas & Steam Turbine Control: Precisely positions fuel control valves, inlet guide vanes (IGVs), and steam control valves to regulate speed, load, and temperature.

• Compressor Control: Manages anti-surge valves, recirculation valves, and guide vanes in centrifugal compressor trains for process stability and surge protection.

• Large Engine Test Stands: Provides accurate control of hydraulic actuators in dynamic testing environments.

• Specialized Industrial Machinery: Used in heavy-duty processes where hydraulic servo control is required for precise force or motion.

Maintenance, Troubleshooting, and Key Features
Maintenance: Regularly inspect for dust accumulation and clean with dry, compressed air. Check terminal connections for tightness. Monitor system diagnostics for any recurring alarms related to servo loop performance.
Troubleshooting: Common issues include erratic valve movement (often due to poor LVDT connections or feedback signal loss), failure to stroke (check output fuses, coil resistance), or constant fault alarms. Use system diagnostic tools to isolate the fault to the card, wiring, or valve.
Salient Features:

• High Resolution and Linearity: Ensures smooth, precise valve positioning across its entire stroke for optimal process control.

• Integrated Protection: Features built-in current limiting and thermal protection for the output drivers.

• Field-Configurable: May allow for adjustment of gain, bias, and other loop parameters via software or physical potentiometers/jumpers to match specific valve characteristics.

• Designed for Harsh Environments: Built with industrial-grade components capable of withstanding typical control room vibration and temperature variations.