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Considering a split phase single phase motor:
The basic motor has a run winding uses 2 poles (or some equivalent), so the motor is activated by the single phase at 180 degree times. This needs a spin to get it started. The direction is according to the direction of the starting spin. It is an induction motor, meaning the rotor has shorting bars. The stator field is connectd to the supply, and induces the required magnetic field in the rotor by transformer action, as for other induction motors.
The starting circuit has the purpose of getting the motor to spin up to sufficient speed for the run winding to take over. The rotation needs some sort of flywheel (inertial) action to carry it through the periods of zero magnetic reaction. It might use a rotor with a commutator for starting, with a centrifugal device that shorts the rotor once the speed is sufficient, so it converts to an induction motor. This method is not used much nowadays. It can have high starting torque for use with compressors for example.
A common approach is to have a second field winding for starting, with poles at 90 degrees to the run winding, so there are four (or equivalent) poles. This is a two phase motor, with a separate field winding for each phase. It can be used as a 2 phase motor with the phases separated by 90 degrees. The second phase is derived from the supply using a capacitor or inductor to cause the current to lead or lag by approximately 90 degrees. The inductor type might use the different inductance of the two windings to get some current separation, and so the starting torque might be lower as this is less than 90 degrees. These were popular because capacitors were expensive. The capacitor type has a capacitor in series with the start winding, and is the most likely type nowadays. Once the rotor is up to speed the start winding can be disconnected by a centrifugal or current operated switch. Some motors run with both windings continuously connected.
Another principle now out of favour because of efficiency issues is used on small motors like fans. It is called a shaded pole motor. Here a special shading pole, part of each stator field pole, is fitted with a shorting winding which causes the field to shift as it builds up on each half cycle, so there is a flick in the correct rotational direction. This has low starting torque.
What else can I help you with?
What is mean by rotor in machines?
a ROTOR is basically any part of a machine that rotates. eg the armature in a motor a STATOR is the part of a machine that is stationary. ie the ROTOR revolves within the STATOR
When the screwdriver motor changes direction?
The magnet is the stator part of the motor,either as a permanent or an electromagnet.It doldrums the rotor past of the motor towards it causing the rotation.
What is centrifuge swing-out rotor?
A Centrifuge Swing-out Rotor is a part of a centrifuge which attaches to the motor and holds the sample tubes. A swing-out, as opposed to a Fixed Angle rotor, has holders that move from vertical to horizontal as the centrifuge speeds up.
How do you reverse the direction of the induction motor?
three-phase motor: Swap the connections of any two phases to the motor.single-phase motor: Usually this can be achieved by reconnecting the starting capacitor from one motor winding to another.Another AnswerAs you have no access to the motor's phases, you must interchange any two of the three line conductors.
Why equalizing holes are provided in turbine rotor disc?
Equalizing holes are provided in turbine rotor discs to ensure uniform pressure distribution across the rotor during operation. These holes help to alleviate any potential imbalance caused by thermal expansion or pressure differentials, which could lead to mechanical stress or failure. By equalizing the pressure, the holes enhance the structural integrity and operational reliability of the rotor, contributing to improved performance and longevity of the turbine.
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.
Induction Motor working principle?
An induction motor works on the principle of electromagnetic induction. When an alternating current flows through the stator windings, it creates a rotating magnetic field. This magnetic field induces a current in the rotor windings, causing it to rotate and drive the attached load.
Why induction motor speed is always less then synchronous speed?
induction motor never runs at synchronous speed, if it does so there would not be any relative speed between stator flux and rotor and no emf will induce in rotor and we can not apply motor principle as we need current carrying conductor in magnetic field.
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.
Explain starting of a wound rotor induction motor?
explain wound rotor
What type classification would a motor with copper bars in the rotor fall into?
although this is not a chemistry question I do have an answer for you. A motor with copper bars is classified as a shaded pole motor. They are low torque motors and do not require any capacitors for run or start functions. hope that helped
What is the principle of 3 phase induction motor?
When three phase supply is given to the three phase stator winding of the induction motor,a rotating magnetic field is developed around the stator which rotates at synchronous speed.This rotating magnetic field passes through the air gap and cuts the rotor conductors which were stationary.Due to the relative speed between the stationary rotor conductors and the rotating magnetic field,an emf is induced in the rotor conductors.As the rotor conductors are short circuited, current starts flowing through it.And as these current carrying rotor conductors are placed in the magnetic field produced by the stator, they experiences a mechanical force i.e. torque which moves the rotor in the same direction as that of the rotating magnetic field. the induction motor can't run at the synchronous speed because at synchronous speed the induction motor can not develop any torque to move the rotor from its stationary position.
How do you convert from slip ring motor to induction motor?
short the rotor terminals.
Does induction motor has rotor winding?
Yes, the induction motor has a rotor winding. It is usually one turn, shorted. This is how the magnetic fields generated in the stator induce a current in the rotor, which subsequently generates a torque from the opposing magnetic fields, stator to rotor.
What did mean by standstill in induction motor?
rotor speed = 0
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.
Why rotor speed less than syncrones speed?
Rotor speed is less than synchronous speed in an induction motor because the motor operates on the principle of electromagnetic induction. The rotor must lag behind the magnetic field produced by the stator to create relative motion, which induces current in the rotor windings. This difference in speed, known as slip, is essential for torque generation. If the rotor speed were equal to synchronous speed, no relative motion would exist, and the motor would produce no torque.
