QUESTION THREE

$($a$)$ Briefly explain the operation of the hysteresis motor

$[3]$

$($b$)$ Define each of the following terms

$($i$)$ Starting torque

$[1]$

$($ii$)$ Running torque

$[1]$

$($iii$)$ Pull in torque

$[1]$

$($iv$)$ Pull out torque

$[1]$

$($c$)$ A small $60$ Hz hysteresis clock motor possess $32$ poles. In making one complete turn with respeet to the revolving held, the hysteresis loss in the rotor amounts to $0\mathrm{.}8$ j calculate

$($i$)$ The pull in and pull out torque

$[2]$

$($ii$)$ The maximum power output before the motor stalls

$[2]$

$($iii$)$ The rotor losses when the motor is stalled

$[2]$

$($iv$)$ The rotor losses when the motor runs at synchronous speed

$[2]$

$($d$)$ Drive an expression for power developed for a salient pole synchronous motor with the help of a phasor diagram with the armature resistance $[5]$

marks$]$

$[$Total: $20$