Slip rings Induction motor provides some advantages like provides high starting torque, low starting current and it improves the power factor. We can add external variable resistance to the rotor of this type of motor. So, we are able to control the speed of this type of motor easily.
What are the advantages of induction motor?
Induction Motor Advantages:
- Induction motors are simple and rugged in construction. …
- Induction motors are cheaper in cost due to the absence of brushes, commutators, and slip rings.
- They are maintenance free motors unlike dc motors and synchronous motors due to the absence of brushes, commutators and slip rings.
What are the applications of slip ring induction motor?
A slip ring induction motor is capable of maintaining the highest torque at any slip. Even a high braking torque can be maintained easily. It is mainly used for high starting torque which makes use of an external resistance. They can help in speed control for lifts, railway traction, elevators, etc.
What is the difference between induction motor and slip ring motor?
Key Differences Between Slip Ring & Squirrel Cage Induction Motor. The motor whose rotor is wound type such type of motor is called slip ring induction motor, whereas the squirrel cage motor, has a squirrel cage type rotor. … The starting torque of the slip-ring motor is high, whereas in squirrel cage motor it is low.
What is the purpose of slip rings and brushes?
The brushes of the slip rings help to connect both ends of the windings and connects with the three insulated slip rings. When an electrical machine is operated, the brushes start to lift up automatically. After this, the electrical current and signal transfer directly from the stator to the rotor parts.
What is advantage and disadvantage of induction motor?
A single phase induction motor, unlike a 3 phase induction motor, does not have a self starting torque. Auxiliaries are required to start a single phase motor. During light load conditions, the power factor of the motor drops to a very low value.
What is the main disadvantage of synchronous motors?
The disadvantages of Synchronous motor includes: Synchronous motors require dc excitation which is supplied from external sources. These motors are not self-starting motors and need some external arrangement for its starting and synchronizing. The cost per kW output is commonly higher than that of induction motors.
What type of starter is used in slip ring induction motor?
Slip-ring motors are widely used when high starting torque is required. Rheostatic and liquid immersed resistance starters are used for starting the slip ring motors.
What is motor slip formula?
Slip speed is the speed difference between the Synchronous speed and Rotor speed. Slip speed = Synchronous speed – Rotor speed = Ns -N. Slip, s = (Ns – N) / Ns.
Why it is called squirrel cage induction motor?
Squirrel cage motors are a subclass of induction motors, which harness electromagnetism to generate motion. They are so-called “squirrel cage” motors because the shape of their rotor – the inner component connected to the output shaft – looks like a cage.
Is slip ring induction motor?
A wound-rotor motor, also known as slip ring-rotor motor, is a type of induction motor where the rotor windings are connected through slip rings to external resistance. Adjusting the resistance allows control of the speed/torque characteristic of the motor.
What is the principle of slip ring induction motor?
Slip rings on a wound rotor AC motor. Once the motor reaches operating speed, the brushes are lifted via the springs and the slip rings are short-circuited via the sliding contact bar. Adding resistance to the rotor windings brings the rotor current more in-phase with the stator current.
How does an induction motor start?
When the supply is connected to the stator of a three-phase induction motor, a rotating magnetic field is produced, and the rotor starts rotating and the induction motor starts. … At the time of starting, the motor slip is unity, and the starting current is very large.
What is the role of slip ring?
A slip ring is an electromechanical device that allows the transmission of power and electrical signals from a stationary to a rotating structure. A slip ring can be used in any electromechanical system that requires rotation while transmitting power or signals.
What is slip speed?
The speed at which the induction motor work is known as the slip speed. … The difference between the synchronous speed and the actual speed of the rotor is known as the slip speed. In other words, the slip speed shows the relative speed of the rotor concerning the speed of the field.
Where is slip ring used?
A slip ring is a method to make an electrical connection from a stationary object to a rotating assembly. These are used in many industrial automation applications and for equipment like tower and jib cranes, as well as cable and hose winders, where a portion can spin freely, while the base is fixed.