The driving member is the Prime Mover to which an Electro Magnetic drum is fitted such that when the Prime Mover rotates, it also forcibly rotates the drum. The Driven member is the Eddy Current Coupling, also called Clutch which consists of a stationary DC Excitation Coil welded securely to a Steel Bracket / Yoke Assembly and a multipole Inductor mounted to the output shaft.
The Assembly of the unit is such that the Inductor shall rotate freely within the drum without touching it.The air gap is an important criterion in the transmission of motor torque to the coupling and thereby to the load.The entire assembly is housed in a rigid GI Frame which is well ventilated. An external DC Voltage adjustable in the range of 0-90V DC is applied to the Excitation Coil after the Motor has attained full speed.
When an electric current passes through the coil, a magnetic flux is formed which will take the path of least reluctance. The flux path in an Eddy Current coupling is completed through the bracket, inductor, drum, and frame.The flux path has three air gaps. Since the air gap is minimum at the Inductor periphery there is a concentration of flux. Since it is housed inside the Drum, there is a varying magnetic field over the drum. Since the drum is a conductor moving over a varying magnetic field, it will induce eddy current. The interaction of the current and flux develops the torque and drives the output. By varying the current through the Coil, the magnetic field strength can be varied and hence the speed difference between the drum and inductor which is essential for the effective torque transmission
Eddy Current Drive is a combination of Prime mover and an Eddy current Coupling. Electromagnetically coupled to each other.These are available in the following constructions
- Air cooled Construction with protection conforming to IP 32
- Water cooled construction with Protection conforming to IP 55
- Totally enclosed Fin cooled construction conforming to IP 54