The most important factor for selection of a centrifugal clutch is the amount of power to be transmitted. Knowing the power available from the drive motor and the operating speed, the torque to be transmitted can be calculated and the size of the clutch determined.

For the vast majority of drives, there is a wide range of clutch types and designs. Our sizes 01 to 13 cover – depending on engagement and operating speeds – a torque range up to ca. 2000 Nm.

To be sure that clutches operate correctly, grease, oil and moisture must be kept away from their friction surfaces.
Performance factor for torque transmission:

The performance factor for torque transmission is a measure of the capacity of a clutch to provide sufficient friction to transmit the power applied to it when the flyweights are in contact with the drum.

Whereas a W-Type clutch has a performance factor of 1.0, an F-Type clutch of the same size with self-increasing effect is capable of transmitting a torque approximately 2.5 times greater at the same speed and with the same flyweight mass.
The asymmetric pivot clutch achieves a power factor of ca. 1.75 or ca. 1.25 depending on the direction of rotation.

Engagement speed:

The engagement speed of a centrifugal clutch indicates the speed at which centrifugal force acting on the mass of the flyweights overcomes the force exerted by the tension springs that restrain them. The flyweights are forced outwards and the friction surfaces start to rub on the inner surface of the clutch drum. The full torque is only transmitted at a higher speed at which the friction surfaces of the flyweights are fully in contact with the clutch drum.

Wear of the friction linings can be minimised by passing quickly through the engagement speed band. The engagement speed is infl uenced by the strength of the springs that restrain the flyweights – the stronger the spring the longer the flyweights are held back. The engagement speed is chosen to suit the operating speed of the drive motor and the power that is to be transmitted. Because the power a centrifugal clutch can transmit rises as the speed of rotation increases, there will be a minimum operating speed for a drive system. This will depend on the application, but is frequently in the order of 600 rpm.