Auxiliary Drive

Replacement for Jaw Clutches

Article lead image

In the past many General Electric (GE) gas turbines, including Frame 3, Frame 5, Frame 6 & Frame 7 machines incorporated a Jaw Clutch to engage the gas turbine (GT) starting drive.

As well as the complication of requiring a control system and actuators to engage the Jaw Clutch engagement could only be done when the GT was at rest. This meant that in the event of a failed GT start, the operator must wait until the machine is stationary before trying to re-start.

The SSS Clutch shown in the illustration replaces the Jaw Clutch. It engages at the instant the starter tries to overtake the GT whether the GT is rotating or stationary. It will also automatically disengage at the instant the GT speeds up relative to the starter.

Arrangement of the original Jaw Clutch showing actuating cylinders.

Incorporating an SSS Clutch between the starting motor torque convertor and the auxiliary gearbox gives the following advantages:

  • Reduced re-start time - the starting drive can be engaged whilst the gas turbine is decelerating from speed. It is not necessary to wait for the gas turbine to come to rest for a re-start, thus saving considerable time before the unit can be generating power.
  • Automatic operation - does not require a servo control system with air or hydraulic cylinders, massively simplifying the system and increasing the reliability and machine availability at the same time as reducing future maintenance.

The SSS Clutch is a direct replacement for the Jaw Clutch with identical interfaces.

A Jaw Clutch prior to being replaced by an SSS Clutch.