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The induction motor can not run at synchronous speed because synchronous speed is a hypothetical speed not a rela speed. Explanation: Synchronous speed can not be achieved in real world because to achieve that speed a vacuum is required with friction which is total impossible in real world.
Why can’t an induction motor run at synchronous speed?
An induction motor always runs at a speed less than synchronous speed because the rotating magnetic field which is produced in the stator will generate flux in the rotor which will make the rotor to rotate, but due to the lagging of flux current in the rotor with flux current in the stator, the rotor will never reach .
Can induction motor runs at synchronous speed?
So, theoretically, the Induction motor can never run at synchronous speed. But due to the reduction of speed, again lag influx will be achieved, and the motor will continue to move at this speed due to flux difference between rotor and stator. In short, an induction motor cannot run at induction speed.
What are the types of induction motor?
Types of Induction Motor: A Concise and Useful Guild
- 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.
What are the advantages of synchronous motor?
Advantages of Synchronous Motor
- The advantage of using synchronous motor is the ability to control the power factor.
- Speed remains constant irrespective of the loads in synchronous motors.
- Synchronous motors are built with wider air gaps than induction motors which make them mechanically more stable.
Why does alternator run at synchronous speed?
A synchronous motor runs at synchronous speed only because it is meant to run like that . It cannot run on a speed other than synchronous speed. Stator(N) links with Rotor(S). For many other applications you can use Induction motor which is simple robust and efficient.
What would happen if synchronous speed is equal to rotor speed?
If the rotor reached synchronous speed, there would be no movement of stator field relative to the rotor conductors, and no induced voltage, current or torque. In order that the no-load losses can be met, the rotor attains a speed less than synchronous.
Why does the speed of induction motor always less than its synchronous speed?
The induction motor always runs at speed less than its synchronous speed. Due to the lag between the flux current in the rotor and the flux current in the stator, the rotor will never reach its rotating magnetic field speed (i.e. the synchronous speed).
What is difference between synchronous and induction motor?
A three-phase synchronous motor is a doubly excited machine, whereas an induction motor is a single excited machine. The armature winding of the synchronous motor is energized from an AC source and its field winding from a DC source. The stator winding of Induction Motor is energized from an AC source.
What is 120 in motor speed formula?
The equation for synchronous speed – the speed of the magnetic field inside the motor stator is 120 x F / P where F is the applied frequency in Hz, and P is the number of poles (always a multiple of 2) in the motor winding. 120 is a constant that gives your answer in revolutions per minute.
What is synchronous speed?
: a definite speed for an alternating-current machine that is dependent on the frequency of the supply circuit because the rotating member passes one pair of poles for each alternation of the alternating current.
What is synchronous speed of motor?
The synchronous speed is the speed of the revolution of the magnetic field in the stator winding of the motor. It is the speed at which the electromotive force is produced by the alternating machine. A machine that runs at synchronous speed is called a synchronous machine.
What is the need of starter for induction motor?
A starter is needed for a three phase induction motor because at the time of starting, if induction motor is started directly, it will draw a huge amount of current which can cause damage to adjoining equipments.
What are 3 types of motor controls?
There are four basic motor controller and drive types: AC, DC, servo, and stepper, each having an input power type modified to the desired output function to match with an application.
When a synchronous motor is running at synchronous speed?
When a synchronous motor is running at synchronous speed, the damper winding produces. eddy current torque. both 1 and 2. no torque.
Why the speed of synchronous motor is constant?
The rotor of a synchronous motor moves at the same speed as the changing, rotating field in its stator. The rotor’s magnetic field is “synchronized” with the stator’s field. Their speed is dependent on the number of poles and the supply frequency. They have a constant speed at a given supply frequency.
What will happen if induction motor speed reaches synchronous speed?
An induction motor can’t development torque at synchronous speed because an induction motor can’t run at synchronous speed because if it runs at synchronous speed the relative speed between the rotor and stator R.M.F will be zero so the torque will be zero.
What is the principle of induction motor?
The motor which works on the principle of electromagnetic induction is known as the induction motor. Electromagnetic induction is the phenomenon in which the electromotive force induces across the electrical conductor when it is placed in a rotating magnetic field.
What is the difference between synchronous speed and rotor speed?
Induction motor with squirrel cage rotor has two different speeds. The synchronous speed refers to the stator rotating magnetic field, which depends on the number of poles and frequency. The other speed is the rotor’s. The rotor speed will be always slower than the stator speed, we call it slip.
Why can an AC induction motor not operate at 0% slip?
In motors the number of rotor slots and stator slots are different and thus cogging (magnetic locking) can’t happen. And thus The slip motor can’t run at rated speed. Torque developed by induction motor is proportional to the slip. At synchronous speed,slip is zero and hence torque developed by the motor is zero.
What is standstill rotor EMF?
When rotor is stationary i.e. s = 1, the frequency of rotor e.m.f. is the same as that of the stator supply frequency. The value of e.m.f. induced in the rotor at standstill is maximum because the relative speed between the rotor and the revolving stator flux is maximum.
