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A motors locked rotor current is the same as the motors starting current. This is the point where the voltage is applied to a non rotating motor, time cycle zero. Because the motor is not rotation and generating a back EMF to oppose the inrush current, the current will go as high as 6 times the running current of the motor.
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What happen if we do the 3 phase winding in rotor of induction motor and give the 3 phase supply only stator winding?
This is how an induction motor normally works, hence the name. The supply voltage is connected to the stator winding(s) and a current is induced in the rotor. A synchronous motor, on the other hand, will have current supplied to the rotor through slip rings and brushes. The rotor current is generally supplied as DC though, or else rectified in the rotor.
Is it necessary to have three phase rotor windings for the transmitter and motor in selsyn motor?
is it necessary to have three phase rotor
Why single phase induction motor has pulsating torque?
according to a mathematical theory the flux produced when an alternating current flows in a single phase winding , this flux is composed of tow equal components which result in tow equal torques , these torques work in opposite direction to each other , hence one causes the rotor to move in a certain direction while the other in the opposite direction . this is the reason why a single phase induction motor instead of its rotor to move in one direction it vibrates. the resultant of these torques is zero. if the motor is caused to move by an external mean say by hand , then the resultant will no longer zero and the motor continue revolving and it speeds up even the external mean is removed, For a single phase induction motor to be a self starting motor some techniques are used like connecting an additional winding called auxiliary winding and a capacitor which in some designs removed automatically when the motor speed come to a certain value while for other designs these elements continue to be connected . Any single phase induction motor is provided by a starting technique so if it vibrates , then this means that the technique is failed
Why is a three phase induction motor self starting?
A brushless DC motor is self-starting using only one magneto-sensitive element because the motor is of a two-phase type and is provided with a detection device which detects towards which of the two phases the rotor is mainly directed. A presetting circuit compares the detected rotor position with the state of an energizing circuit in order to set this circuit so that the energizing circuit energizes the stator phases for said specific rotor position in such a way that starting of the motor is guaranteed, although initially with an undefined direction of rotation. By presetting the commutating direction of the energizing circuit the rotor subsequently locks onto the field and rotates in the correct direction if it has started in the incorrect direction
Formula for rotor speed on a cage rotor induction motor?
Nr = NS * (1-s) Nr = rotational speed (rev/sec) Ns = Synch Speed (rev/sec) s = Slip (%)
What are No Load And Locked Rotor tests on a three phase induction motor?
Doing a No Load test of a 3-phase induction motor involves the measuring of current, voltage, torque etc with no load on the rotor shaft, meaning that it is free to turn but is not driving anything else. Similarly a Locked Rotor test involves the measuring of current, voltage, torque etc with the rotor shaft "locked" i.e. prevented from turning, which is the worst loading condition the motor would ever have to contend with.
What is the useful of open end winding of induction motor?
Standard induction motor has a closed squirrel cage rotor, where as open ended induction motor has split phase rotor.
What happens if 3 phase supply is given to stator and rotor both in a induction motor?
its impossible to give suppy to rotor of an induction motor,because of it a closed path for circulating currents.
What are No Load And Blocked Rotor tests on a three phase induction motor?
There is no such thing as a "Blocked" Rotor test so that must be a misunderstanding of the correct description, which is "Locked" Rotor test.For more information see the answer to the Related Question shown below.
Is a three phase induction motor self starting?
A three-phase motor has a steady rotating magnetic field generated by the stator coil, and the rotor just follows the field.
Why you use brushes for single phase induction motors?
There no brushes in an induction motor. The rotor is independent and is a short-circuited cage of parallel bars.
What are the two different forces acts in opposite direction on the rotor of single phase induction motor?
An induction motor has an AC power source applied to the stator and an AC source applied to the rotor, through slip rings. The rotor spins a sub synchronous speed, which creates the phase shift between rotor AC and stator AC. This phase shift (known as slip) is what creates the torque.
What happen if we do the 3 phase winding in rotor of induction motor and give the 3 phase supply only stator winding?
This is how an induction motor normally works, hence the name. The supply voltage is connected to the stator winding(s) and a current is induced in the rotor. A synchronous motor, on the other hand, will have current supplied to the rotor through slip rings and brushes. The rotor current is generally supplied as DC though, or else rectified in the rotor.
A particular 3 phase induction motor has a LRA of 100 amps What is its approximate starting current?
LRA (locked rotor amperage) is not considered. Starting current for a motor is usually in the neighbourhood of 300% of the FLA (full load amps). The FLA is taken from the motor's nameplate.
How do you increase starting torque in cage type 3-phase induction motor's?
by adding external resistance to the shaft of rotor
What is difference of blocked rotor and locked rotor protection of motor?
What is difference of blocked rotor and locked rotor protection of motor?Read more:What_is_difference_of_blocked_rotor_and_locked_rotor_protection_of_motor
What is induction motor?
Induction motor is an AC electric motor which uses electromagnetic induction to induce the electric current in the rotor to produce torque.
