What determines the rotation of a shaded pole motor?

What determines the rotation of a shaded pole motor?

It’s easy to determine the direction of rotation of a shaded pole motor. The rotor will always turn from the middle of the pole towards the “shaded” portion of the pole. The stator contains the shading poles. The position of shading poles determines the direction of rotation of the rotor.

Why is the efficiency of a shaded pole motor low?

A shaded pole motor is the simplest form of a single phase motor and is very low in cost. It develops a rotating field by delaying the build up of magnetic flux through part of the pole structure. The magnetic flux in the unshaded portion increases with the current through its winding.

Why the shaded pole motor starting torque is low?

The speed of the shaded pole induction motor is inversely proportional to the number of poles used in the motor. The shaded pole induction motor produces a very small starting torque about 50% of full load torque. The efficiency of the shaded pole motor is low because of continuous power loss in the shading coil.

Is shaded pole motor operates at low power factor?

The other name of the copper ring is a shaded ring, where it acts as a secondary winding motor. It rotates only in one direction particularly and reverses moment is impossible. This motor has very high power induction losses and also has a very low power factor. Starting torque induced in the motor is very low.

Are shaded pole motors reversible?

Shaded-pole motors of the asymmetrical type shown are only reversible by disassembly and flipping over the stator, though some similar looking motors have small, switch-shortable auxiliary windings of thin wire instead of thick copper bars and can reverse electrically.

What is the function of shaded pole motor?

The various applications of the shaded poles motor are as follows: They are suitable for small devices like relays and fans because of their low cost and easy starting. Used in exhaust fans, hairdryers, and also table fans. Used in air conditioning and refrigeration equipment and cooling fans.

Can the direction of rotation of a shaded pole motor be reversed?

Although direction of rotation is not normally reversible, some shaded-pole motors are wound with two main windings that reverse the direction of the field.

How to control the speed of a shaded pole motor?

Voltage-only control of a Shaded Pole (SP) motor is an acceptable method and is the most common. It doesn’t work on other types of AC motors, but because of some of the inherent design aspects of what make a SP motor work in the first place, the torque / speed relationship is more or less linear, or can be made to appear so.

What is the copper ring on a shaded pole induction motor?

The copper ring is also called the shaded ring. This copper ring act as a secondary winding for the motor. The shaded pole motor rotates only in one particular direction, and the reverse movement of the motor is not possible. Why the Shaded Pole Induction Motor designs for low power rating?

How does winding of shaded pole affect magnetic field?

The winding of shaded pole delays the creation of magnetic field in the portion of the stator poles. This produces a magnetic field in the shaded portion that is approximately 90oapart from the magnetic field produced in the main portion of the pole. That means two fluxes are obtained which are displaced both in time and space.

How does the rotating part of an induction motor work?

As in other induction motors, the rotating part is a squirrel-cage rotor. Starting is by means of a design that uses a continuous copper loop around a small portion of each motor pole, as illustrated in Figure 5-51. Currents in this copper loop delay the phase of magnetic flux in that part of the pole enough to provide a rotating field.