Induction motors generally will have low starting torque compared to dc series motor. Slip ring induction motor have big advantage of having high starting torque compared to squirrel cage motor. Therefore slip ring induction motors are generally employed where load requires high starting torque or good speed control.
What is the difference between slip ring and squirrel cage induction motor?
The slip ring motor has brushes for transferring the power whereas the squirrel cage motor is brushless. The copper loss in the phase wound motor is high as compared to squirrel cage motor. The efficiency of the slip ring motor is low whereas the squirrel cage motor has high efficiency.
What are the advantages of cage rotor over slip ring induction motor?
Require less maintenance (as there are no slip rings or brushes) Good speed regulation (they are able to maintain a constant speed) High efficiency in converting electrical energy to mechanical energy (while running, not during startup)
What is the purpose of slip ring in induction motor?
Functionally, slip rings provide a continuous transfer of power, signals, or data. Specifically, in AC motors, they transfer resistance to the rotor windings. Commutators, on the other hand, are used in DC motors to reverse the polarity of current in the armature windings.
What are the advantages and drawbacks of a wound rotor induction motor compared to a squirrel cage induction motor?
Wound Rotor Induction Motor Qualities
Excellent starting torque for high inertia loads. Low starting current compared to squirrel cage induction motor. Speed is the resistance variable over 50% to 100% full speed. Higher maintenance of brushes and slip rings compared to squirrel cage motor.
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.
What is the purpose of squirrel cage?
A synchronous motor may have a squirrel-cage winding embedded in its rotor, used to increase the motor starting torque and so decrease the time to accelerate to synchronous speed. The squirrel cage winding of a synchronous machine will generally be smaller than for an induction machine of similar rating.
Which type of motor has high starting torque?
DC motor has high starting torque.In a series motor the same current flows through the armature and the field winding.
Which type of starter is used only in slip ring induction motor?
Rotor resistance starter is used for slip ring induction motors of high ratings.
What are the advantages and disadvantages of induction motor?
Induction motors always operate under lagging power factor and during light load conditions they operate at very worst power factor (0.2 to 0.4 lagging). Some of the disadvantages of poor power are increase in I2R losses in the system, reduction in the efficiency of the system.
What happens if the slip of induction motor is 1?
This is the reason; slip is never zero in an induction motor. Slip = 1, means that rotor is stationary. Negative value of slip in induction motor can be achieved when the rotor speed is more than the synchronously rotating magnetic flux.
How does an induction motor start?
A three-phase Induction Motor is Self Starting. When the supply is connected to the stator of a three-phase induction motor, a rotating magnetic field is produced, and the rotor begins rotating and the induction motor starts.
What are the types of induction motor?
Types of Induction Motor: A Concise and Useful Guild
- Types of Induction Motors. Types of Single-Phase Induction Motors. Split Phase Induction Motors. 2&3. Capacitor Start and Capacitor Start Capacitor Run Induction Motors. Shaded Pole Induction Motors. Types of Three-Phase Induction Motors. Squirrel Cage Induction Motor. Slip-ring or Wound Rotor Induction Motor.
Why the starting torque of squirrel cage induction motor is low?
It suffers from the disadvantage of a low starting torque. It is because the rotor bars are permanently short-circuited and it is not possible to add any external resistance to the rotor circuit to have a large starting torque.
Do squirrel cage motors have brushes?
Construction: A slip ring motor gest a complex construction owing to the use of slip rings and brushes, whereas, squirrel cage motors are simply-built. .
What is the biggest advantage of a wound rotor induction machine?
Advantages of Wound Rotor Motor
High starting torque – Slip ring induction motor can provide high starting torque due to the presence of external resistance in the rotor circuit. High overload capacity – Slip ring induction motors have high overload capacity and smooth acceleration during heavy loads.