I. Product Overview

CPC-II series I/P current-to-pressure converter, an original American Woodward product, a core component of the hydraulic speed control system for steam turbines / gas turbines. It receives 4-20mA electrical control signals from the governor and linearly converts them into 3-15psi standard pneumatic pressure to drive pneumatic oil actuators and valve actuators. It is compatible with the entire series of Woodward speed control systems, including 505/2301A/SPM-D11 (8440-1706D), for retrofitting of power plant steam turbines and for retrofitting of old units with hydraulic speed control systems.

 Core Electrical & Pneumatic Parameters Table

Project Technical Specifications

Electrical Control Input DC 4-20mA standard analog signal (0%→3psi, 100%→15psi)

Air Source Supply Clean and dry instrument air, 20-30psi supply pressure, recommended 25psi

Pneumatic Output Linear 3-15PSI air pressure output, corresponding to fully closed → fully open

Conversion Accuracy Full range ±0.5% FS, zero point / range can be adjusted by on-site knob

Air Consumption Approximately 0.5SCFM (standard cubic feet / minute) under 20psi condition

Operating Temperature -40℃ to +85℃, resistant to oil, dust industrial conditions

Shell Material Aluminum cast shell, total machine net weight ≈2.3kg

Installation Method Panel-mounted fixed / base bracket installation, not DIN rail

Protection IP54, CE, explosion-proof ATEX certification (explosion-proof option available)

Key Functions

Precise linear conversion of electrical signal to pneumatic signal

Speed control controller (8440-1706D, 8290-191) outputs 4-20mA speed control instructions, this machine outputs the corresponding air pressure to drive the steam turbine control valve oil actuator, serving as an intermediate bridge between electrical control and old pneumatic actuators.

Zero point and range on-site fine adjustment

The body comes with zero position (Zero) and range (Span) adjustment screws, allowing on-site calibration without disassembly of wiring, suitable for different stroke steam valves.

Built-in air source filtration and stabilization

Equipped with a small air filter to reduce the failure rate of valve core due to impurities in the air source.

Supporting Equipment & Application Scenarios

Supporting Controller: 8440-1706D, 8290-191, 505, 2301A full series of Woodward speed control boards

Application: Small and medium-sized industrial steam turbines, waste heat power generators, gas turbines, refinery turbine units, self-owned power stations, replacement of old mechanical I/P valves for liquid control in old mechanical I/P valves