Woodward UG MAS Governor
Pressure compensated, hydraulic governor with milliamp speed setting
The UG MAS speed setting system allows remote speed setting using a 4–20 mA current loop. This remote control of engine speed is especially useful in marine applications using milliamp signals instead of the more traditional pneumatic pressure signal.
The system consists of a UG-8 Dial governor with a special cover and a separate final driver. The cover of the UG-8 includes a stepper motor that is directly connected to the speeder screw in the UG-8 governor. On top of the stepper motor, the position of the motor is measured with a feedback potentiometer connected with a worm and gear.
In operation, the final driver compares the milliamp input signal with the voltage signal derived from the feedback potentiometer and runs the stepper motor to the position in which the milliamp signal corresponds with the feedback signal. This results in a speed setting proportional to the milliamp signal.
Additional features of the UG MAS include:
Manual Speed Setting
During electrical operation, the manual speed setting follows the electrical speed setting. On loss of electric power, the governor speed remains at the last speed setting and can be changed by activating the manual speed setting using the knob on the governor.
Speed droop permits load division and balancing among prime movers operating in parallel to drive a common shaft. Speed droop can be set with a knob on the front panel of the governor.
Maximum Speed Limit
A minor alarm contact on the driver box can be used to limit the maximum speed setting (for example, in case of low lube oil pressure or high cooling temperature.) This reduced speed setting is adjustable with a potentiometer in the driver.
Some of the UG auxiliary functions (such as solenoid shutdown) can also be incorporated into the UG MAS.