TG611‐13/‐17 Governor with Overspeed Test Device

Applications

TG611 Governors are self-contained, mechanical-hydraulic, speed-droop governors for use on small steam turbines driving pumps, compressors, or generators, where isochronous (constant speed) operation is not required. These governors are directly coupled to the steam-turbine’s rotor or auxiliary shaft to sense and control turbine speed. Designed for API-611based turbine  applications, these governors include a special Overspeed Test  Device, allowing  controlled and safe turbine overspeed trip testing.

Description

TG611 governors are mechanical-hydraulic speed-droop governors for controlling small steam turbines. These governors control turbine speed by sensing turbine rotor speed via their input drive shaft, comparing this speed to an internal speed setpoint, then using a rotary output terminal shaft connected to the turbine’s governor valve to control turbine inlet steam flow. This self-contained governor utilizes an integrated drive-shaft-driven ballhead assembly to sense turbine speed, and an integrated drive-shaft-driven oil pump to create the necessary output force to move/control the turbine’s governor valve. The governor output is a serrated terminal shaft that extends out each side of the governor housing and rotates up to 40° to accurately control the turbine’s inlet steam valve(s).

Different models are available depending on the output shaft force and input driveshaft speed range required. The TG611 governor’s (turbine) speed setpoint is set and adjusted via a speed-setting screw located on the unit’s cover plate. TG611 governors are available in two different work outputs: 16 Nm (12 lb-ft) and 23.7 Nm (17.5 lb-ft). These governors are hydraulically powered for a high work output, and are available for three different speed ranges.

Like most mechanical governors, the TG611 governor uses its output terminal shaft position as a feedback signal for stability. By using this stabilizing method, turbine speed will “droop” a certain percentage as load increases (shaft position increases).