Overrunning Clutch Selection Guide
OVERRUNNING: DUAL DRIVE AND TWO SPEED DRIVE
High-Speed Overruning and High-Speed Engagement: (Overruning speed = 700 RPM and up) (Engaging speed = 700 RPM and up)
Example of fan or pump drive
Turbine
Reducer
Cam Clutch A
Cam Clutch B
Motor
Fan
Figure 23: Typical High-Speed Overrunning Application
Clutch B overruns when the turbine drives the fan, and it engages when the motor drives the fan. The driving devices can be changed over without switching the clutch. This is because the difference in the speed of rotation between the motor and turbine turns the Cam Clutches on and off, and the driving device rotating the fastest is connected automatically to the fan. Overrunning and engagement of the Cam Clutches are performed continuously at speeds faster than 700 r/min. Please reference Figure 23 . to drive a turbine. The turbine is then used to help drive the pump. If the pressure available is too low to rotate the turbine at high speed, the Cam Clutch overruns. However, when the rotating speed of the turbine reaches the rotating speed of the motor, the Cam Clutch engages automatically and the pump is driven by both the turbine, and the motor. Thus, power consumption equivalent to the turbine output can be saved. Since energy loss during overrunning and engagement of the Cam Clutch is extremely small, this system produces results for pumps with an output as low as 10 hp (7.5 kW). Setup requires only installation of a Cam Clutch and a turbine, providing a high efficiency energy recovery system with low running costs. Please reference Figure 24 .
This example shows a high-speed system in which a fan is driven by a dual drive system consisting of a motor and a turbine. The Cam Clutches are used for automatic switching between the driving units. The fan is normally driven by the Cam Clutch on the turbine side. When starting, or when steam pressure to the turbine drops, the motor takes over from the turbine to drive the fan. Cam Clutch A engages when the turbine drives the fan, and it overruns when the motor drives the fan. Conversely, Cam
Example of energy saving pump (power recovery system)
Hydraulic Turbine
Cam Clutch
Pump
Motor
Figure 24: High-Speed Energy Saving Application
Application of Cam Clutches in an energy saving pump (power recovery system) shows how highly effective energy saving can be achieved with the aid of Cam Clutches. The motor-driven pump discharges high-pressure liquid, which, after circulating, is used
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