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Hitachi Nico Transmission Co.,Ltd.

Image : Reduction Gear with Torque Limiter

The reduction gear has been developed for driving generator of gas turbine generating system, and shall function as a gear to reduce the speed of a gas turbine to a generator's speed through the medium of planetary gear, and also as a torque limiter.
The torque limiter shall be of a hydraulic clutch type where technique of a wet type multi-disc clutch. Starting torque when excessive torque works shall be set up by clutch operating oil pressure, since a hydraulic clutch system is adopted.
The clutch plate shall not cause any heat nor energy loss due to slipping, as the clutch plate shall slide out only in the instant that excessive torque is in action and be used in the condition of being clutched-on completely. Additionally, a torque-limiter-only type (HLH type) that does not have speed reduction mechanism is in production.


  • The gear shall prevent a gas turbine from being overloaded without shutting off transmission of the power, and can be used as a substitute of a conventional shear pin.
  • Starting torque can be set up precisely. (within ±5%)
  • Set up torque can be adjusted easily.
  • Since the gear is provided with the function as on-off clutch, a gas turbine can be started independently of a generator so as to shorten the starting time.