different type of electrical motors

7/29/2019 different type of electrical motors

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DC motors:-1.Self-excited dc motor2.Separately-excited dc motor

3. stepper motor4.switched reluctance dc motor

5.Permanent magnet motor

Universal motor(ac &dc)AC motors:-1.Synchronus motor

2.Induction motor

3.shaded pole motor


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DC MOTOR

Self excited dc motor

DC shunt motor:-

Since the field winding is placed in parallel witharmature, it is called a shunt winding and the motor is

called a shunt motor.

Dc series motor:-

The series motor provides high starting torque and is able to move

very large shaft loads when it is first energized.


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1.Short shunt motor

2.Long shunt motor

Separately excited dc motor

This type of DC motor is constructed such thatthe field is not connected to the armature.


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Stepper motor

Stepper motors can be

rotated to a specific angle in

discrete steps with ease,

and hence stepper motors

are used for read/write head

positioning in computer.

Stepper motors were andstill are often used in

computer printers, optical

scanners, and digital

photocopiers


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Switched reluctance motors

The switched reluctance motor (SRM) has no brushes or

permanent magnets, and the rotor has no electric currents.

Instead, torque comes from a slight mis-alignment of poles on

the rotor with poles on the stator. The rotor aligns itself with the

magnetic field of the stator, while the stator field stator windings

are sequentially energized to rotate the stator field.

As the rotor turns, different windings will be energized, keeping

the rotor turning.

6/4 Pole Switched reluctance motor


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AC MOTORS

Induction motor When a 3-phase ac supply is given to the stator

then rotating air gap flux will be produced andthat rotating flux will cut the stationary rotor

conductors.So emf is induced in the rotor,

consequently current will be produced.Thiscurrent interacts with the rotating flux to develop

the torque and now rotor begins to rotate.


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Universal motors A series-wound motor is referred to as a universal motor when

it has been designed to operate on either AC or DC power. It

can operate well on AC because the current in both the field

and the armature (and hence the resultant magnetic fields) will

alternate (reverse polarity) in synchronism, and hence the

resulting mechanical force will occur in a constant direction of

rotation.

An advantage of the universal motor is that AC supplies may be

used on motors which have some characteristics more commonin DC motors, specifically high starting torque and very compact

design if high running speeds are used


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Synchronus motor

Synchronus motor is a doubly excited machine.

It works on the principle that when an ac supply is

given to the armature winding,then an ac current will

flow in the winding.With the excitatation of field

winding by dc,it produces magnetic field which

interacts with armature current to develop a torque to

rotate the rotor of the motor.


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Shaded-pole motor

A shaded-pole motor is a type of AC single-phase inductionmotor. It is basically a small squirrel cage motor in which the

auxiliary winding is composed of a copper ring surrounding a

portion of each pole.This auxiliary winding is called a shadingcoil. Currents in this coil delay the phase of magnetic flux for

that pole (a shaded pole) enough to provide a rotating magnetic

field.The direction of rotation is from the unshaded side to the

shaded (ring) side of the pole. The effect produces only a low

starting torque compared to other classes of single-phasemotors.


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Permanent-magnet motors

A permanent-magnet motor does not havea field winding on the stator frame, instead

relying on permanent magnets to provide the

magnetic field against which the rotor field

interacts to produce torque. Compensating

windings in series with the armature may be

used on large motors to improve

commutation under load. Because this field is

fixed, it cannot be adjusted for speed control.Permanent-magnet fields (stators) are

convenient in miniature motors to eliminate

the power consumption of the field winding.


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conclusion

From above description we have familiar with

the different types of motors and we conclude

that all the motors have their specific featureswhich are used in different field of

applications.for example DC series motor are

used to drive the locomotive as a traction

motor,single phase induction motor is used fordomestic purpose for pumping and fan,dc

separately excited motor is used in crane or

hoist load etc.


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different type of electrical motors

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