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100

What factors help to determine the amount of torque developed by an electric motor?

strength of magnetic field developed by amount of current

100

Explain the significance of each digit of the right hand in describing "the right hand motor rule"

thumb=direction of motion
index=fixed field of flux
middle=current flow

100

what is the best method of controlling the RPM of a DC motor?

Control the amount of field current. Less field current, higher RPM

100

How can the direction of rotation of a DC motor be reversed? When will this be done?

By changing the direction of current flow either in the armature or in field winding, not both.

100

what are the 3 types of DC motors?

Series, shunt and compound.

200

this cuts power to starter when current drops below specified limits

under current relay

200

what type of energy losses exist in DC motor

Copper & Iron loss

200

disadvantages of a series type DC motor?

poor voltage regulation under changing load
No speed control, may self destruct if over-sped

200

what is the biggest advantage of a shunt type dc motor?

speed regulation- maintains constant speed

200

Advantages of AC motors over DC

Light weight, more efficient, suitable for constant speed, good starting torque

300

what is a universal motor??

DC series motor that operates on AC, possible on DC.

300

if an inspection of dc motor shows brittle discolored wire insulation of field winding, what does this indicate?

overheating, overload, bearing problems

300

what is the most common type of dc motor used in aircraft engine starting application

series

300

Biggest disadvantage of shunt type DC motor?

Increase of load, decrease in voltage. Poor torque

300

rotor assembly type of AC induction motor

squirrel cage

400

what is slip

difference between motors sync speed and actual shaft speed

400

function of the centrifugally operated switch found in most single phase ac..

disconnects start winding after the motor reaches 25% of its speed

400

3 basic types of single phase AC induction motor

split phase, capacitor start and shaded pole

400

direction of rotation of a shaded pole is determined by

where the shading ring is

400

why is # of poles per phase important?

to determine syncronous speed

500

a certain electric motor develops 6.3 ft/lbs of torque at 2500 rpm... What is the HP rating????

2.99 HP (3)

500

What happens to the counter EMF developed in the armature of a motor as the motor's RPM's increase. What effects does this have on the motors ability to generate torque?

As motors rpm increases, so does the EMF, this causes less armature current and weakening ability of the motor to generate torque.

500

how is the rotation of a shaded single phased motor changed?

only by changing the position of the shaded portion of the poles

500

a certain motor is rated at 3.73 KW.. what is its HP rating???

5HP

500

most common trouble of an induction ac motor

bearings