AC Theory cont...

A multispeed can operate at more than one predetermined set speed eg/half speed or full speed, whereas a varible speed motor is one that can provide almost infinite stepless possibilities up to full speed

• -Tapped field universal motor
• -Two speed split phase motor

Speed change is acheived by having two run windings

A centrifugal switch is set up with double contact to switch between the full speed winding and the other speed winding

It acts as a cooling device in a motor

The laminsted iron core

Because it looks like an excercise wheel used for squirrels

Copper or cast alluminium

Lower starting current but increased starting torque applications

Double cage rotor

It gives the necessary current phase shift between poles to establish a rotation in the stator of the 3-phase induction motor

It depends on the phase sequence of the supply

The order in which the line voltages attain their immediately succeeding maximum values

By simply interchanging any two of the line conductors supplying the motor

The induction motor is made up of several closed circuits causing currnets to run  in them, these currents set up a magnetic field that interacts with the rotating stator magnetic field to produce torque. The magnitude of this torque depends on the relative motion between the rotating field and the rotor