answersLogoWhite

0

In brief,in a 3 phase SQIM,there are 3 windings per pole in the stator physically 120 degree apart,each of which is fed from per phase of a balanced 3 phase ac supply.As the magnetic field due to current in each winding varies with time as the current is alternating,the resultant field will be found to keep on changing its direction with time in a circular locus,magnitude being constant because of this setup which can be shown mathematically.Thus a rotating flux of constant mag links the rotor which induces an emf in the rotor,though initially both rotor & stator are static.

Another Answer

A three-phase induction motor is, essentially, a transformer. The 'primary' windings being the stator's field windings, and the 'secondary' winding being the bars of the rotor. For this reason, induction motors are often termed 'rotary Transformers'. So emfs are induced into the bars by 'transformer action'.

Unlike a 'static' transformer, however, the secondary voltages and the frequencies of the voltages vary with the speed of the rotor.

User Avatar

Wiki User

10y ago

What else can I help you with?

Continue Learning about Engineering

What is the difference between a DC motor and a generator in terms of EMF?

During the operation of a DC motor, EMF is created across its terminals using an external source. Whereas, in a DC generator EMF is created across its terminal based on principle of dynamically induced EMF. So talking in terms of EMF, in DC motor EMF is consumed by the motor coil and utilized to rotate the axle. On the other hand, in DC generator EMF developed across coil is transfered to a load or a battery and consumed by them.


When pole flux of dc motor is zero what is its speed?

when the pole flux is zero there is no induced emf in the armature conductor of dc machine as a result of this there is no back emf for controlling action so speed become dangerously high or we can say it will be infinite.


How much emf is needed for running a dc motor?

It depends entirely on the design of the motor.


Difference between back EMF and induced EMF?

An induced electromotive force (emf) is an induced voltage. Voltage (emf) causes current flow, and this induced voltage will cause a current that is called the induced current.We might also add that the induced current will cause a magnetic field to expand about the current path, and this field will "sweep" the conductor. The sweeping of the conductor by that expanding magnetic field will set up an emf that will oppose the emf that was creating it.CommentTechnically, there is no such thing as an 'induced current'. It is voltage that is induced. Any current flows as a result of that induced voltage being applied to a load. But that current is certainly NOT induced!


Does motional emf call induced emf?

yes indused emf is also called motional emf. If an open coil is subjected to a variable magnetic field, at the ends of the coil a potential difference is induced which is called induced emf. If a coil is connected to an emf source and switched on, the rising current will produced an variable magnetic field which in turn produces an emf. It is called back emf.

Related Questions

What is Back emf of DC motor?

In dc motor, the armature conductors are revolving in the magnetic field and emf is induced in the armature conductors. The direction of the induced emf is in opposite direction to the applied voltage as per Flemings left hand rule. So, the induced emf in motor is called as back emf or counter emf. Vydehi


What is the difference between a DC motor and a generator in terms of EMF?

During the operation of a DC motor, EMF is created across its terminals using an external source. Whereas, in a DC generator EMF is created across its terminal based on principle of dynamically induced EMF. So talking in terms of EMF, in DC motor EMF is consumed by the motor coil and utilized to rotate the axle. On the other hand, in DC generator EMF developed across coil is transfered to a load or a battery and consumed by them.


What is emf induced in a motor's coil that tends to reduce the current in the coil of the motor?

BACK emf induced in a motor's coil that tends to reduce the current in the coil of the motor. The answer should be 'back'.


When pole flux of dc motor is zero what is its speed?

when the pole flux is zero there is no induced emf in the armature conductor of dc machine as a result of this there is no back emf for controlling action so speed become dangerously high or we can say it will be infinite.


The back emf indcuced in the armature is AC or DC?

only in dc motor...


How much emf is needed for running a dc motor?

It depends entirely on the design of the motor.


What is the factors determining induced emf in dc machine?

The factors determining induced electromotive force (emf) in a DC machine include the strength of the magnetic field, the number of turns in the coil, the speed of rotation of the armature, and the angle of the coil relative to the magnetic field lines. The induced emf is directly proportional to the magnetic field strength, the number of turns in the coil, and the speed of rotation, while it is also affected by the angle of the coil in relation to the magnetic field. These factors collectively determine the magnitude of the induced emf in a DC machine.


What is the difference between Counter-electromotive force and back emf?

They are Same for dc motor


Difference between back EMF and induced EMF?

An induced electromotive force (emf) is an induced voltage. Voltage (emf) causes current flow, and this induced voltage will cause a current that is called the induced current.We might also add that the induced current will cause a magnetic field to expand about the current path, and this field will "sweep" the conductor. The sweeping of the conductor by that expanding magnetic field will set up an emf that will oppose the emf that was creating it.CommentTechnically, there is no such thing as an 'induced current'. It is voltage that is induced. Any current flows as a result of that induced voltage being applied to a load. But that current is certainly NOT induced!


Does motional emf call induced emf?

yes indused emf is also called motional emf. If an open coil is subjected to a variable magnetic field, at the ends of the coil a potential difference is induced which is called induced emf. If a coil is connected to an emf source and switched on, the rising current will produced an variable magnetic field which in turn produces an emf. It is called back emf.


What is the induced emf in case (a)?

In case (a), the induced emf is the electromotive force generated in a coil or conductor due to a changing magnetic field.


In colomn answer of difference between statically indused emf and dynamicaly indused emf?

Statically induced emf is produced by the relative motion between a conductor and a magnetic field, while dynamically induced emf is generated due to a change in the magnetic field strength experienced by a conductor. Statically induced emf does not require any physical movement of the conductor, while dynamically induced emf is produced when the magnetic field changes over time.