Non-Contact Torque Transmission

Ringfeder Power Transmission has expanded its range of magnetic couplings by four new models to be used in highly sensitive and hard-to-reach areas.

The latest generation of magnetic and hysteresis disc couplings made by Ringfeder Power Transmission is a reliable solution to transmit and limit torques without establishing direct contact between the driving and the driven element. The new arrivals in the portfolio are perfectly suitable for all areas which call for a hermetic separation of the drive and the output side and make high demands in tightness and hygiene. Their non-contact mode of operation perfectly qualifies the wear-free couplings to be used in the chemical industry, under water or in closed containers. In comparison to standard couplings, maintenance is reduced to a minimum since the otherwise customary care and servicing of the shaft bearings and seals is no longer required.

The models GWM 5202.3 and GWM 5204.3 are permanent-magnetic synchronous couplings with two opposed discs which have been equipped with powerful magnets. The torque is transmitted by the magnetic field via an air gap which allows operation through housing walls without establishing direct contact. The coupling is connected with the shaft by means of bore and clamping screws (GWM 5202.3) or clamping hubs (GWM 5204.3). In the event of overload, the magnetic field forces are exceeded; as a consequence the coupling slips and thus protects the system from being damaged. In contrast to mechanical solutions, the magnetic couplings work wear-free even in case of high rotational speed and during longer periods of disengagement.

The new series is completed by the hysteresis disc couplings GWM 5202.4 and GWM 5204.4. The two models are Ringfeder’s answer to their customers’ needs in transmitting a constant torque across a wide speed range. Instead of permanent magnets, the company employs high-quality hysteresis material which allows changing the poles easily. The system consists of two halves: one half of a magnetic disc coupling and the other of a hysteresis disc coupling. The advantage of this combination: in the event of an overload, the coupling starts slipping and then continues to transmit the nominal torque. The coupling now serves as a break. Resulting breaking energy is released into the environment as lost heat.

All models of the new magnetic couplings are fit for operation in temperatures ranging from minus 30°C to 120°C . At customer’s request special designs which resist temperatures of up to 300°C are available, too. As an option Ringfeder Power Transmission offers an enclosure for the magnets. The new couplings compensate angle misalignment of up to three degrees and parallel offsets of up to six millimeters. On top of that they offer a low moment of inertia as well as a simple setup and uncomplicated assembly. For more information on the products of Ringfeder Power Transmission please visit