ELPT 1441 Motor Control Final Exam
Most industrial motors operate on voltages that range from ________ volts. - correct
answer-240 to 480
How many current sensing devices are required by the NEC to protect a single phase
motor operated on 240V? - correct answer-one
The control components in a schematic diagram are always shown ______________. -
correct answer-as they would be when the circuit is turned off or de-energized
What is meant by the term "soft start" when describing the starting of an electric motor?
- correct answer-The motor is brought up to speed over some period of time
Which of the following is not a characteristic of overload relays? - correct answer-They
must open the circuit immediately if the motor becomes overloaded.
What is the main characteristic of a schematic diagram? - correct answer-Schematic
show control components in their electrical sequence without regard for physical
location
Control devices that are intended to provide direct control of the motor must have larger
contacts than devices intended to control the coil of a magnetic starter. The devices
intended to connect the motor directly to the power line are referred to as ________. -
correct answer-line voltage devices
How many current sensing devices are required by the NEC to protect a three phase
motor operated on 480V? - correct answer-three
All overload relays contain a set of normally closed contacts. To what and how are
these contacts connected? - correct answer-they are connected in series with the coil of
the motor started
Bridge type contactors use ___________. - correct answer-one movable contact and
two stationary contacts
What type of overload relay contains a knob for adjusting the trip current of the relay
from between about 85% and 115% of the rating of the overload heater? - correct
answer-bimetal strip type
What are eddy currents? - correct answer-they are currents that are induced into the
metal core of a solenoid intended to operate on alternating current
Most industrial motors operate on voltages that range from ________ volts. - correct
answer-240 to 480
How many current sensing devices are required by the NEC to protect a single phase
motor operated on 240V? - correct answer-one
The control components in a schematic diagram are always shown ______________. -
correct answer-as they would be when the circuit is turned off or de-energized
What is meant by the term "soft start" when describing the starting of an electric motor?
- correct answer-The motor is brought up to speed over some period of time
Which of the following is not a characteristic of overload relays? - correct answer-They
must open the circuit immediately if the motor becomes overloaded.
What is the main characteristic of a schematic diagram? - correct answer-Schematic
show control components in their electrical sequence without regard for physical
location
Control devices that are intended to provide direct control of the motor must have larger
contacts than devices intended to control the coil of a magnetic starter. The devices
intended to connect the motor directly to the power line are referred to as ________. -
correct answer-line voltage devices
How many current sensing devices are required by the NEC to protect a three phase
motor operated on 480V? - correct answer-three
All overload relays contain a set of normally closed contacts. To what and how are
these contacts connected? - correct answer-they are connected in series with the coil of
the motor started
Bridge type contactors use ___________. - correct answer-one movable contact and
two stationary contacts
What type of overload relay contains a knob for adjusting the trip current of the relay
from between about 85% and 115% of the rating of the overload heater? - correct
answer-bimetal strip type
What are eddy currents? - correct answer-they are currents that are induced into the
metal core of a solenoid intended to operate on alternating current
