Core Information Extraction of Model 9907-167 (Woodward 505E Digital Governor)
1. Basic Product Positioning and Power Specification
Model 9907-167 is a specific variant of the Woodward 505E Digital Governor, designed exclusively for extraction, admission, or extraction/admission steam turbines. It is a 32-bit microprocessor-based control system that integrates turbine control and an Operator Control Panel (OCP) into a single package. This model is distinguished by its power supply type: it uses LVDC (Low Voltage Direct Current) with an input voltage range of 18–32 Vdc, making it suitable for applications where low-voltage DC power is the primary energy source.
Its core function is to precisely control key turbine parameters, including speed (or load) and extraction/admission pressure (or flow), by regulating the high-pressure (HP) and low-pressure (LP) control valves. It supports both standalone operation and integration with a plant’s Distributed Control System (DCS), eliminating the need for additional hardware to adapt to different application scenarios (such as generator-driven or mechanical-driven turbines), thereby reducing equipment costs and delivery cycles.
2. Compliance and Hazardous Location Certification
2.1 Hazardous Location Ratings
North America: UL Listed for use in Class I, Division 2, Groups A, B, C, and D hazardous environments. It has a T3C temperature rating at 60 °C ambient (UL File E156028) and is also suitable for non-hazardous locations.
Europe: Compliant with EN60079-15 (Electrical apparatus for explosive atmospheres – Type of protection ‘n’), making it applicable to Zone 2, Group II potentially explosive atmospheres.
Note: Only units bearing the official certification mark meet the above hazardous location requirements.
2.2 Directive Compliance
EMC Directive: Adheres to 89/336/EEC and its amendments, meeting EN50081-2 (radiation emissions) and EN50082-2 (electromagnetic immunity) standards to ensure stable operation in electromagnetic environments.
Low Voltage Directive: Complies with 73/23/EEC to guarantee electrical safety during installation and operation.
ATEX Directive: Conforms to 94/9/EEC for equipment used in potentially explosive atmospheres, aligning with European safety standards for hazardous industrial settings.
2.3 Wiring and Peripheral Requirements
Wiring Standards: Must follow North American Class I, Division 2 or European Zone 2 wiring methods, as applicable, and comply with the requirements of the local Authority Having Jurisdiction (AHJ).
Wire Temperature Rating: For field wiring used in environments where the ambient temperature is expected to exceed 50 °C, the wire must have a rated temperature of at least 75 °C to prevent insulation degradation.
Peripheral Compatibility: All peripheral equipment (such as transducers, relays, and sensors) must be suitable for the specific location (hazardous or non-hazardous) where the 9907-167 is installed.
3. Core Technical Specifications
3.1 Power Supply and Physical Characteristics
Power Input: LVDC 18–32 Vdc. The internal power supply includes two breaker-protected output channels (VA1 and VA2), each providing 24 Vdc ±10% with a maximum output current of 200 mA. VA1 powers current inputs and auxiliary devices, while VA2 powers current outputs and auxiliary devices.
Enclosure Ratings:
Standard enclosure: NEMA 4 / IP54, providing protection against splashing water and dust ingress.
Optional bulkhead-mounted enclosure (Part Number 8923-439): NEMA 4X / IP66, offering enhanced corrosion resistance and protection against harsh environmental conditions (e.g., coastal or chemical plants).
Operating Temperature:
Standard enclosure: -25 to +65 °C (ambient air temperature).
Optional bulkhead-mounted enclosure: -20 to +60 °C (ambient air temperature).
Weight: Approximately 4 kg (standard enclosure); approximately 10 kg (optional bulkhead-mounted enclosure).
Fuse Specifications: Internal slow-blow fuses protect the power supply circuit. For the 18–32 Vdc model, the fuse rating is 6.25 A (77 VA maximum power consumption) to prevent damage from overcurrent.
3.2 Speed Sensing and Control Performance
Speed Inputs: Two configurable speed inputs, compatible with either Magnetic Pickup Units (MPUs) or proximity probes (jumper-selectable).
MPU Input: Input impedance of 2 kΩ; minimum input amplitude of 1 Vrms (100 Hz–25 kHz) and 2 Vrms (25 kHz–32 kHz); maximum input amplitude of 25 Vrms.
Proximity Probe Input: Capable of sensing speeds as low as 0.5 Hz; input voltage range of 16–28 Vdc.
Speed Range: Sensing range of 100 Hz–32 kHz; trip-point frequency range of 250 Hz–25 kHz (convertible to rpm via the programmed number of MPU gear teeth).
Trip Accuracy: ±(0.05% × Trip Point in Hz + 2 Hz), ensuring precise overspeed protection.
MPU Fault Protection: Programmable MPU Fail Setpoint (100–25,000 rpm) and MPU Fail Timeout (1 second to 533 minutes 20 seconds). If the turbine speed does not exceed the MPU Fail Setpoint within the timeout period, the unit triggers a trip to prevent unsafe operation.
3.3 Inputs and Outputs
3.3.1 Analog Inputs
Total Count: 6 analog inputs.
Input 1: Dedicated to extraction/admission signals (4–20 mA).
Inputs 2–5: Configurable for signals such as remote speed setpoint, synchronization, or kW load; compatible with 2-wire loop-powered or self-powered transducers (jumper-selectable).
Input 6: Fully isolated, designed for non-isolated sources (e.g., DCS); input impedance of 200 Ω for all analog inputs.
Failure Detection: Triggers an alarm if an analog input signal is out of range (below 2 mA or above 22 mA). For critical inputs (e.g., extraction/admission), the unit can be programmed to trip the turbine upon signal failure.
3.3.2 Contact Inputs
Total Count: 16 contact inputs.
Dedicated Inputs (4): External emergency shutdown, external reset, raise speed setpoint, lower speed setpoint.
Generator Application-Dedicated Inputs (2): Generator breaker and utility tie breaker (required if the turbine drives a generator).
Configurable Inputs (10–12): 10 configurable inputs for generator applications; 12 for non-generator applications (e.g., overspeed test, start permissive, idle/rated selection).
Electrical Characteristics: Each contact input draws 2.5 mA when closed; requires at least 1 mA and 14 Vdc to recognize a closure.
3.3.3 Actuator Outputs
Total Count: 2 actuator outputs (for HP and LP valves), configurable for Woodward actuators (20–160 mA) or non-Woodward actuators (4–20 mA).
4–20 mA Output: Maximum impedance of 360 Ω (sum of actuator impedance and wire resistance).
20–160 mA Output: Maximum impedance of 45 Ω (sum of actuator impedance and wire resistance).
Additional Features: Supports dithering (to prevent valve sticking) and an 11-point linearization curve (configurable via Service Mode) to optimize valve response accuracy.
Fault Protection: Monitors output current; triggers a trip if an overcurrent (e.g., short circuit) or undercurrent (e.g., open circuit) is detected.
3.3.4 Relay Outputs
Total Count: 8 Form-C relay outputs.
Dedicated Relays (2): Shutdown relay (de-energizes on shutdown) and alarm relay (energizes on alarm; optional blinking function for critical alarms).
Configurable Relays (6): Programmable for status indication (e.g., overspeed test active, frequency control) or level switching (e.g., speed, extraction pressure).
Contact Ratings: Dependent on load type (resistive, inductive, tungsten, motor); typical ratings include 10 A at 28 Vdc (resistive) and 3 A at 115 Vrms (resistive).
3.3.5 Communication Ports
Modbus Ports (2): Support RS-232, RS-422, or RS-485 protocols, compatible with ASCII or RTU transmission modes. Used for interfacing with DCS, operator panels, or other control systems.
PC Port (1): A 9-pin Sub-D connector dedicated to uploading/downloading configuration files and firmware updates.
If you have any PLC DCS inquiries, please contact Cheryl freely
