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Woodward 9907-314
Product Name: CPC-II Current-to-Pressure Electro-Hydraulic Converter, Dual-Channel Redundant Version
Product Overview: Dual-channel redundant CPC-II electro-hydraulic converter with two fully independent electrical and coil circuits inside. If one channel fails, the other seamlessly takes over control to achieve redundant fault tolerance. Used in turbine units with high reliability requirements, it receives two independent 4-20 mA command signals and outputs one hydraulic control oil pressure. A single channel failure will not cause the unit’s regulation to fail.
Detailed content
Technical Specifications:
- Dual-channel independent input signals: Two 4-20 mA DC paths
- Power Supply: Two independent 24 VDC supplies
- Medium: Turbine lubricating oil
- Supply Pressure: 0.6-1.0 MPa
- Output Control Pressure: 0-0.55 MPa
- Operating Temperature: -20°C to 75°C
- Protection Class: IP54
Functional Features:
- Dual independent electrical and coil circuits, dual power supplies, dual signal inputs, no-disturbance switching upon single channel failure.
- Internal pressure closed-loop feedback; output oil pressure is not affected by supply pressure fluctuations.
- Channel fault self-diagnosis with fault alarm signal output to DCS.
- Automatic voting between the two signal paths; faulty channel is automatically masked.
- Depressurization on total power loss (both paths), valve safely closes.
Application Scenarios: Redundant control of main control valves for large generating set steam turbines, redundant electro-hydraulic conversion for important cogeneration units, industrial turbine servo systems requiring continuous operation without shutdown.
Performance Parameters:
- Linearity: ≤ ±0.5% FS
- Hysteresis: ≤ 0.4% FS
- Channel switching disturbance-free, switching disturbance less than 0.2% FS
- Full-range response time: ≤ 90 ms
Material Composition:
- Valve body base: Cast aluminum alloy
- Valve core and sleeve: Hardened stainless steel
- Seals: Oil-resistant fluororubber + PTFE composite seal
- Electrical compartment: Cast aluminum housing with two sets of independent circuit board assemblies inside
Structural Features: Integrated hydraulic valve body, with two fully independent circuit boards and drive coils integrated inside the upper electrical compartment; two sets of independent electrical wiring terminals externally; the hydraulic part shares the same valve core and output oil chamber; the hydraulic chamber and electrical compartment are physically isolated.
Working Principle: Two independent 4-20 mA signals and two 24 VDC power supplies enter the device. The device performs voting computation on the two signals internally, prioritizing the normal channel signal to drive the servo valve core. If one signal or power supply fails, the device automatically switches to the intact channel, with no disturbance in hydraulic output. If both power supplies are lost, the valve core opens the pressure relief path, the output oil pressure returns to zero, and the external servo spring closes the valve.
Installation Requirements: Priority vertical installation, electrical compartment prohibited from facing downward. The supply pipeline shall be equipped with a 3 μm filter with differential pressure alarm engaged. The two signal cables shall be laid separately, and the two shielded cables shall each be independently single-point grounded. The two 24 VDC power supplies must come from two independent power modules; sharing the same power supply is not allowed.
Usage Precautions: Verify that the two channels are powered independently before commissioning. It is strictly forbidden to open the electrical compartment cover while energized.
