NCCER Electrical Level 2 Module 2
Motors: Theory and Application
Sections 4-6
The two primary types of motor enclosures classified by NEMA are ____. - Answer-
open and totally enclosed
An open AC squirrel cage motor that makes use of form-wound coils and an
insulation system is known as a(n) _____. - Answer- sealed windings(type)
The NEMA frame designation for gasoline pump motors is ____. - Answer- G
The letters FLA on a motor nameplate stand for ____. - Answer- full-load amps
To determine the horsepower rating of a motor that is already installed and in place,
____. - Answer- check the nameplate data
Most industrial motors are NEMA Design ____. - Answer- B
The multiplier to the nameplate horsepower rating is called the _____. - Answer-
service factor
The code requirements for motor disconnects are covered in ___. - Answer- 430.102
All motors must have a thermal protector if their voltage rating is greater than _____.
- Answer- 600V-1,000V
To protect the motor from overloads and starting failures, use a ____. - Answer-
thermal protector
When studying the operation of electric motors, it is important to remember that
magnetic lines of force ____. - Answer- do not cross
If a motor has 4 poles and is operating at a frequency of 60Hz, its synchronous
speed is _____. 120(60Hz)/4= 1,800 rpm - Answer- 1,800 rpm
The type of motor most likely to be used in a location with flammable dust and torque
fluctuations is a ____. - Answer- squirrel cage induction motor
A heating system is most likely to use a _____. - Answer- single-phase induction
motor
With a constant-torque load, the horsepower ____. - Answer- varies in direct
proportion to the speed
Motors: Theory and Application
Sections 4-6
The two primary types of motor enclosures classified by NEMA are ____. - Answer-
open and totally enclosed
An open AC squirrel cage motor that makes use of form-wound coils and an
insulation system is known as a(n) _____. - Answer- sealed windings(type)
The NEMA frame designation for gasoline pump motors is ____. - Answer- G
The letters FLA on a motor nameplate stand for ____. - Answer- full-load amps
To determine the horsepower rating of a motor that is already installed and in place,
____. - Answer- check the nameplate data
Most industrial motors are NEMA Design ____. - Answer- B
The multiplier to the nameplate horsepower rating is called the _____. - Answer-
service factor
The code requirements for motor disconnects are covered in ___. - Answer- 430.102
All motors must have a thermal protector if their voltage rating is greater than _____.
- Answer- 600V-1,000V
To protect the motor from overloads and starting failures, use a ____. - Answer-
thermal protector
When studying the operation of electric motors, it is important to remember that
magnetic lines of force ____. - Answer- do not cross
If a motor has 4 poles and is operating at a frequency of 60Hz, its synchronous
speed is _____. 120(60Hz)/4= 1,800 rpm - Answer- 1,800 rpm
The type of motor most likely to be used in a location with flammable dust and torque
fluctuations is a ____. - Answer- squirrel cage induction motor
A heating system is most likely to use a _____. - Answer- single-phase induction
motor
With a constant-torque load, the horsepower ____. - Answer- varies in direct
proportion to the speed
