Slip Ring Motors

In electrical engineering, a slip ring is a mechanical device that transfers electrical power and signals between stationary and rotary systems. Slip rings are small, compact devices and can be used in a number of ways to simplify operation of a system or improve mechanical performance. They are also often selected because they help to avoid cable twisting.

In a motor, they are commonly used to reduce the amount of current required at start-up. This is achieved by inserting a graphite brush that rubs against the rotor windings and creates an electric field which generates an alternating current in the motor. This induced current then produces a torque which helps to accelerate the motor to its normal operating speed. The motor continues to operate in this manner until it reaches its normal running speed, at which point the brushes are shorted out and the motor runs normally.

This type of motor is particularly suitable for applications where there are large moment of inertia, such as mills, fans, crushers and transportation machinery. It can also be used to drive large electric shovels and wind turbines. These slip ring motors are also very common in industrial plants because of their low starting current and high load capacity.

What Are Slip Ring Motors?

When selecting the correct slip ring for your application it is important to review all of the specifications and properties to ensure that you are choosing the right one. There are a wide range of existing models and emerging ones, some of which feature innovative features that can enhance the way your machine operates. It is also essential to identify what type of environment and working conditions the slip ring will be exposed to as this will impact the material it is made from, its current and circuits, size and dimensions and other factors.

A slip ring induction motor can be used as a replacement for any AC or DC motor that uses brushes. This is because the design of these motors means that they can operate at a much lower starting current than a traditional squirrel cage motor, while still producing a high load torque. This type of motor is also able to work well under extreme working conditions.

A typical construction of this type of motor includes a fixed stator with a number of slots to accommodate a 3-phase winding circuit and a rotor which contains the conductive graphite brushes. The three start terminals on the rotor and the three end terminals on the stator connect through slip rings to transmit mechanical power. The rotor has a cylindrical laminated steel core with semi-closed grooves to accommodate the 3 phase insulated windings. The slip rings help to prevent the rotor from attracting dust, which would otherwise interrupt the contact between the brushes and the conductive metal. Once the motor reaches its normal operational speed, the brushes are shorted out and the power is transferred directly between the stator and rotor.