FIG. $2$: $3-$Phase AC Motor

$26.$ What roles do the following play in the generation of this power:

$($A$)$ the rotor windings

$($B$)$ the stator windings

$($C$)$ the diesel$-$engine

$27.$ What instrument is used to measure the insulation resistance of electrical equipments? How is it used?

$28.$ These designations are associated with rotating electrical machines. What do they represent?

i$)$ Stator

ii$)$ Rotor

iii$)$ Armature

iv$)$ Magnetic Field

$29.$ Why do periodic insulation of electrical equipment have to be taken?

$30.$ Explain the terms: $\text{'}$IP$\text{'}$ and 'Insu Class' found on the nameplate of a motor

$31.$ Explain why a dc supply is preferred over ac supply for the excitation of electrical generators.

Name three $(3)$ types of motor enclosures used on the ship. State which areas on the ship they would likely be used.

$32.$ The details on the name$-$plate of an ac motor are $3-$phase, $440V,60Hz,1740rpm.$ How many poles would the motor be made of and what will be its slip$-$speed?