11/05/2024 12:06 PM
BOMA: Electrical Motor Controls. Exam
Questions With Correct Answers
A holding contact or maintaining contact in a magnetic motor starter is normally connected in parallel
with the? - answer✔Stop push button, start push button, and starter coil
The armatures of both AC and DC contactors must move freely or? - answer✔all the contacts may weld
together
Which of the following devices prevent motors from drawing too much current? - answer✔overloads
The primary difference between a motor starter and a motor contactor is the starter has an? -
answer✔overload protection
The purpose of a reduced motor is to? - answer✔reduce voltage on motor starter
Two speed motors require 2 sets of overloads to monitor the motor heating characteristics at each
speed? - answer✔true
Over current protection is provided for an electric motor to prevent damage to the windings from the
heating effect of excessive current? - answer✔true
The current interrupting capability of a fuse breaker is to? - answer✔the maximum amperage it should
conduct during normal operation
Reduce voltage starting is used as a means of? - answer✔reducing the starting current
The speed of an AC squirrel cage motor can be changed by? - answer✔Changing the number of poles
A short circuit ground fault device may consist of? - answer✔A fuse and a circuit breaker
A small size motor starter is given the designation of 00? - answer✔True
In a process control, the time it takes for a change in the process to be felt at the measuring device is
called? - answer✔delay
A relay is a device that can transfer an action from one circuit to another without an electrical
connection between the two circuits? - answer✔True
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11/05/2024 12:06 PM
What is meant by EP switch? - answer✔Electric Pneumatic operated switch
When using a fuse jumper for troubleshooting, be sure never to connect the jumper between? -
answer✔L1 and L2
The first thing to check when a system is down and won't run at all is? - answer✔The AC power supply
Improper alignment of the pole faces can cause excessive hum in a AC electromagnetic or solenoid? -
answer✔True
To indicate a good diode an ohm meter should? - answer✔Low resistance in one direction and high
resistance in the other direction
Unbound resistance readings between the windings of a three-phase motor indicates the motor
windings may? - answer✔Be breaking down
A motor control circuit that allows the motor to automatically start after power is restored provides low
voltage release? - answer✔Is said to be wired across the line is provided
What determines the speed of an induction motor? - answer✔Number of poles
What is made when an electric current flow through the turns of a coil? - answer✔A magnetic field
Rheostats are generally used in a motor controls for? - answer✔Specially designed motors
How do you change the rotation of a three phase motor? - answer✔Change any 2 of the 3 wires
The actual full load amps of a motor are found? - answer✔Nameplate of the motor
The centrifugal switch of a single phase induction motor is connected in series with the ______
windings? - answer✔start windings
Synchrononomous motors have? - answer✔stator and magnetic force
Return overload current in reference to motor circuits refers to? - answer✔Any load current that
exceeds rated motor current
A generator? - answer✔Changes mechanical power into electrical power
A machine that converts mechanical power into electrical power is called a? - answer✔A generator and
alternator
Distilled water should be added to a battery when? - answer✔when level is below the plates
The electrical energy that a battery can deliver is measured in? - answer✔amphours
When manually switching from normal to auxiliary power can be accomplished by? - answer✔using an
automatic transfer switch