Description

Woodward  9907-838  Digital governor

Woodward 9907-838 is a digital governor used for controlling steam turbines. It belongs to the Woodward 505 series and is a digital speed regulator based on a microprocessor. It features high control accuracy, good stability and simple operation. The specific introduction is as follows:

Functional features:
Multiple startup sequences: It features automatic startup sequences of hot start and cold start, and has a temperature input option, allowing for the selection of the appropriate startup mode based on different working conditions.
Critical speed avoidance: It can achieve critical speed avoidance on the three-speed band, preventing the steam turbine from operating in the critical speed range and reducing risks such as vibration.
Rich alarm and trip inputs: It features ten external alarm inputs and ten external DI trip inputs, which can promptly detect external abnormal conditions and trigger corresponding protection actions. At the same time, it provides trip and alarm event indications with relevant RTC timestamps, facilitating fault detection and analysis.
Dual-speed and load dynamic control: Supports dual-speed and load dynamic control, which can better adapt to different load changes and ensure the stable operation of the steam turbine.

Other functions: It features peak speed indication for overspeed tripping, zero speed detection, remote drop, frequency dead zone and other functions. It also provides three normal operation modes: configuration, operation and calibration, to meet the needs of different usage scenarios.
Input/output configuration:
Speed input: It includes two redundant speed inputs that can accept signals from magnetic pickup devices, eddy current probes or proximity probes, ensuring the reliability of rotational speed measurement.

Analog input: There are 8 analog inputs that can be configured into any of the 27 functions, meeting the measurement and input requirements of various parameters.
Contact input: Additionally, there are 20 contact inputs. The first four are by default used for closing, raising the speed setting value, resetting, and lowering the speed setting value. The rest can be configured as needed.
Control output: It features two 4-20 mA control outputs and eight C-type relay contact outputs, which can be used to control external devices such as control valves and relays.
Front panel design: The front panel is equipped with an emergency trip key, a backspace/delete key, a Shift key, as well as view, mode, ESC and Home keys, etc. It also features a navigation cross key, soft key commands and four leds for associated control and hardware status, facilitating operation and status viewing by the operator.

Technical specifications: Analog input is a 4-20 mA channel (back circuit power supply); The electromagnetic compatibility immunity complies with the EN 61000-6-2 standard; The shell type is IACS UR E10 (Merchant ship), featuring ATEX, IP-54 and pollution level 3. The input voltage is low 18-36 VDC isolated. The operating temperature and storage temperature are both -22 ℉ to 158℉ (approximately -30 ℃ to 70℃). The screen size is an 8.4-inch LCD screen.
Communication capability: Supports multiple network types such as RS-485 serial network, Genius network, Profibus network, Ethernet, etc., facilitating communication and integration with other devices or systems.