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A slip ring is simply an electromechanical device that transmits signals between the stationary and the rotating parts of an electromechanical system. Slips are supposed to improve mechanical performance, simplify system operation and damage-prone wires dangling from movable joints. Also known as rotary electrical interfaces or rotating electrical slip ring connector, these slip rings are commonly used in slip ring motors and electric generators for alternating current and a lot more objects.
Typically slip ring is made of a stationary metal contact brush that rubs on the outermost diameter of a rotating metal ring. The turning metal then, conducts electric signal making a connection through the stationary brush to the metal ring, which is the actual function of lip rings.
Difference in the slip ring and squirrel cage Induction Motor
There are a lot of basic differences between a slip ring rotor (also known as wound rotor) and a squirrel cage induction motor. Even the function of slip rings are very different than its counterpart. Both of them are used in induction motors separately.
Before understanding the difference, let's go through the definition of each of them.
Slip ring motor: A slip ring induction motor, also known as phase wound motor employs the wound rotor. Its component includes a laminated cylindrical shaped core having a half-closed slot placed on the outer periphery. It carries a three-phase winding.
Squirrel cage induction motor: It employs a rotor which squirrel cage type, consisting of the cylindrically laminated core which has the semi-closed round slots and provided by a short circuit on the either ends with a copper ring or aluminium ring, which is known as short-circuit ring.
1. The major difference between them is that the slip ring's motor comes with an external circuit that controls the speed of a motor. On the other hand, the squirrel cage motor does not have any external circuit and it is not possible to add one since the motor bar is spotted permanently at the end of that ring.
2. The rotor of the slip ring's motor is constructed as a type of a slip ring while the in the squirrel cage, it is constructed in its same type.
3. The slip ring's motor can also be termed as the phase wound rotor while the other is known as the cage motor.
4. The construction of slip ring motors are somewhat complicated while the squirrel cage motor construction is simpler.
5. In slip ring motor, a rotor which is resistance to the starter can be used while in squirrel cage motor, it cannot be used.
6. The starting torque in the motor is very high and there is the presence of brushes. The same is absent in the squirrel cage motor and it has low starting torque.
7. For slip ring motor, a frequent maintenance is required while for the squirrel cage motor, the maintenance might not be needed so often.
8. In comparison with the squirrel cage motor, the copper loss is high in the slip ring's motor while the efficiency is lower.
9. The speed of slip ring's motor can be controlled but it is not possible for the squirrel cage motor.
The slip ring's motor has the overloading capacity which is high, same as compared to any squirrel cage motor, and it still runs smoothly under the heavy loads.