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If a three phase induction motor runs at a speed greater than synchronous speed?
Wiki User
∙ 14y ago
When an induction motor is pushed over synchronous speed it will become a generator and will deliver power back to the utility.
Wiki User
∙ 14y ago
Wiki User
∙ 12y agoIf the motor is synchronous, then its speed will not change as the load changes.
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Is a 3 phase motor a Synchronous motor?
A synchronous motor can be a type of 3-Phase AC motor, or not.A synchronous motor is defined by the period of the rotor being synchronized with the frequency of the stator windings' current. The stator windings might be 3-Phase or not (2-Phase would work).Also synchronous motors are not the only type of 3-Phase AC motors. An induction motor could also be 3-Phase AC and has a few advantages and disadvantages over a synchronous motor.
Does a induction motor need excitation?
The induction motor is the special kind of motor which runs below and above the synchronous speed. which the synchronous motor runs nearly equal the synchronous speed. The operation of synchronous motor runs with dc field excited hence separate dc field current is given to the field circuit. where as the induction motor the field and main field is drawn from the same supply hence no excitation is required. But due to this separate starting mechanism has to be required in case of the single phase induction motor.
Why does the rpm of a three phase motor decrease as the number of poles increase?
The synchronous speed is 6000 divided by the number of poles for a synchronous motor on 50 Hz, and 5-10% less than that for an induction motor. On a 60 Hz supply these speeds are 20% higher.
Is 3 phase induction motor is self starting?
Yes, that is one of the major advantages of a three-phase induction motor.
How can you reverse the direction of rotation in an induction motor?
A single phase induction motor has two sets of coils and a centrifugal start switch. The start winding is in series with the start switch. The start winding provides a rotating magnetic field in one direction enabling the motor to start. The motor can be reversed by reversing the connections of either the start winding or the run winding but not both.
Why is the speed of synchronous motor is more then induction motor?
Synchronous motors run at synchronous speed. An induction motor that has the same number of poles must run at a sub-synchronous speed to create a second magnetic field (a field that is at a different phase angle) to generate torque.
Is a 3 phase motor a Synchronous motor?
A synchronous motor can be a type of 3-Phase AC motor, or not.A synchronous motor is defined by the period of the rotor being synchronized with the frequency of the stator windings' current. The stator windings might be 3-Phase or not (2-Phase would work).Also synchronous motors are not the only type of 3-Phase AC motors. An induction motor could also be 3-Phase AC and has a few advantages and disadvantages over a synchronous motor.
Does a induction motor need excitation?
The induction motor is the special kind of motor which runs below and above the synchronous speed. which the synchronous motor runs nearly equal the synchronous speed. The operation of synchronous motor runs with dc field excited hence separate dc field current is given to the field circuit. where as the induction motor the field and main field is drawn from the same supply hence no excitation is required. But due to this separate starting mechanism has to be required in case of the single phase induction motor.
Which type of the motor is used in fan?
Low-power (a few watts) might use a synchronous motor, most fans use an induction motor. Above a couple of horse-power it might be a 3-phase induction motor.
Why single phase induction motor always runs below the synchronous speed?
For exactly the same reason as three-phase motors always run below synchronous speed. If they were to run at synchronous speed then no voltage and, therefore, no rotor current will be induced into the rotor to drive it.
What type of motor is used in table fan?
Small house fans run on single-phase induction motors.
Why 3 phase induction motor never atteined sinkronas speed?
Induction motors run at sub synchronous speeds because the slip (difference between synchronous and actual speed) causes, or controls the electric field strength in the motor. As more load is put on the motor, the motor's speed decreases, increasing slip, and increasing the electric field strength.
Why does the rpm of a three phase motor decrease as the number of poles increase?
The synchronous speed is 6000 divided by the number of poles for a synchronous motor on 50 Hz, and 5-10% less than that for an induction motor. On a 60 Hz supply these speeds are 20% higher.
Why each phase no load power factor of 3 phase induction motor is not same?
That indicates a fault in the induction motor.
Is 3 phase induction motor is self starting?
Yes, that is one of the major advantages of a three-phase induction motor.
How many Slip rings in synchronous motor?
If the synchronous motor is single phase then there are two slip rings & if this motor is three phase so the slip rings are three in number. Correction; I have never seen a single phase synchronous motor. It would cost more that it was worth. A synchronous motor has a separately excited field. If the excitation comes from a stationary DC source it has 2 slip (collector) rings. A brushless induction motor has no slip rings because the exciter armature rotates and so do the rectifiers. A permanent magnet motor, used with variable frequency drives, is another type of synchronous motor that has no slip rings. A three phase motor with 3 slip rings is a Wound Rotor motor. Wound rotor motors are variable speed motors that were used for such applications as bridges and cranes before variable speed drives.
How do you reverse single phase ac motor to generator?
how reversing an ac single phase induction motor to wark as induction generator
