Motor Control Exam Questions and Answers 100% Solved
Define Full Load Current or FLA - Answers nameplate current when motor is running
Define Starting Current or inrush current - Answers the current that is drawn by starting the motor
Define Rotor - Answers rotating portion of an ac motor
define Locked rotor current - Answers current drawn from line when rotor is jammed
define Contactor - Answers device used to establish or interrupt a power circuit. no olr protection
define HP rated - Answers able to establish or interrupt motor full load current
define Overload Relay - Answers device that provides overload protection for motor only
What are the main parts of a overload relay - Answers overload heater, contact and thermal connection
Define Motor starter - Answers device rated to start a motor, it provides overload protection and can
stop motor
What does the motor starter consist of - Answers contacts and overload relay
Define Combination starter - Answers a starter with a manual disconnection means built into the same
enclosure
Define Across the line starter - Answers starter designed to start motor with full line voltage
define reduced voltage starter - Answers starter designed to start motor with reduced line voltage
define Manual starter - Answers starter with contacts that must be manually opened and closed
mechanically
define Magnetic starter - Answers Starter with contacts that open and close electromagnetically
define Normally Open - Answers in the de-energized state it is normally open
define Normally Closed - Answers in the de-energized state it is normally closed
define Auxiliary Contacts - Answers additional control contacts in addition to main contacts
define Chatter - Answers noise in contacts, caused by attraction and release of the armature by the
electromagnetic coil
define shading coil - Answers copper ring around part of the contacts magnetic face that is used to
prevent chatter and premature wear to contacts
define Blow out coil - Answers electromagnetic coil that deflects and defuses arc that may occur when
circuit is interrupted
, define power circuit - Answers carries the power from the line to motor
define Control Circuit - Answers carries signals either electrical or mechanical to control devices
define Low voltage release - Answers on failure of supply voltage the motor restarts automatically.
define 2 wire control - Answers low voltage release
define low voltage protection - Answers on failure of power supply and return of power, it must be
manually restart before it can be turned on again
define Maintain Contact or Seal in contact - Answers contacts that are in parallel with the start button
which keeps coil energized after push button has been released
define Schematic diagram - Answers shows components in their electrical relationship, not physical
location. best for trouble shooting
define Wiring Diagram - Answers Shows components mounted in their general locations and their
physical relationship
define Jogging - Answers moving machine with short jabs that are quickly repeated of opening and
closing circuit
define Control Relay - Answers similar to contacts, used to control circuit components
define interlock - Answers can be electrical or mechanical. is a safety to prevent from two operations
happening at the same time
define plugging - Answers rapid stop or braking of motor by reversing the phase sequence of a 3 phase
motor
define service factor - Answers rating factor that can be applied to FLA
define Insulation Code - Answers this indicates the ambient temperature the motor is rated to run in
What are the three types of common manual motor starters - Answers Drum, toggle, push button
List three significant rating found on manual motor starters - Answers Volts, amps and Horsepower
What are the different ratings for the drum switch - Answers 120V=1.5HP and 240V=3HP
What are the different ratings of HP for the common starters - Answers Toggle is 1HP, push button is
5HP and drum is 1.5-3HP
What is the difference of a single phase toggle switch and single pole light switch - Answers The toggle
switch has HP, voltage and amp ratings and also hp rated contacts. Is also able to interrupt locked rotor
current
Define Full Load Current or FLA - Answers nameplate current when motor is running
Define Starting Current or inrush current - Answers the current that is drawn by starting the motor
Define Rotor - Answers rotating portion of an ac motor
define Locked rotor current - Answers current drawn from line when rotor is jammed
define Contactor - Answers device used to establish or interrupt a power circuit. no olr protection
define HP rated - Answers able to establish or interrupt motor full load current
define Overload Relay - Answers device that provides overload protection for motor only
What are the main parts of a overload relay - Answers overload heater, contact and thermal connection
Define Motor starter - Answers device rated to start a motor, it provides overload protection and can
stop motor
What does the motor starter consist of - Answers contacts and overload relay
Define Combination starter - Answers a starter with a manual disconnection means built into the same
enclosure
Define Across the line starter - Answers starter designed to start motor with full line voltage
define reduced voltage starter - Answers starter designed to start motor with reduced line voltage
define Manual starter - Answers starter with contacts that must be manually opened and closed
mechanically
define Magnetic starter - Answers Starter with contacts that open and close electromagnetically
define Normally Open - Answers in the de-energized state it is normally open
define Normally Closed - Answers in the de-energized state it is normally closed
define Auxiliary Contacts - Answers additional control contacts in addition to main contacts
define Chatter - Answers noise in contacts, caused by attraction and release of the armature by the
electromagnetic coil
define shading coil - Answers copper ring around part of the contacts magnetic face that is used to
prevent chatter and premature wear to contacts
define Blow out coil - Answers electromagnetic coil that deflects and defuses arc that may occur when
circuit is interrupted
, define power circuit - Answers carries the power from the line to motor
define Control Circuit - Answers carries signals either electrical or mechanical to control devices
define Low voltage release - Answers on failure of supply voltage the motor restarts automatically.
define 2 wire control - Answers low voltage release
define low voltage protection - Answers on failure of power supply and return of power, it must be
manually restart before it can be turned on again
define Maintain Contact or Seal in contact - Answers contacts that are in parallel with the start button
which keeps coil energized after push button has been released
define Schematic diagram - Answers shows components in their electrical relationship, not physical
location. best for trouble shooting
define Wiring Diagram - Answers Shows components mounted in their general locations and their
physical relationship
define Jogging - Answers moving machine with short jabs that are quickly repeated of opening and
closing circuit
define Control Relay - Answers similar to contacts, used to control circuit components
define interlock - Answers can be electrical or mechanical. is a safety to prevent from two operations
happening at the same time
define plugging - Answers rapid stop or braking of motor by reversing the phase sequence of a 3 phase
motor
define service factor - Answers rating factor that can be applied to FLA
define Insulation Code - Answers this indicates the ambient temperature the motor is rated to run in
What are the three types of common manual motor starters - Answers Drum, toggle, push button
List three significant rating found on manual motor starters - Answers Volts, amps and Horsepower
What are the different ratings for the drum switch - Answers 120V=1.5HP and 240V=3HP
What are the different ratings of HP for the common starters - Answers Toggle is 1HP, push button is
5HP and drum is 1.5-3HP
What is the difference of a single phase toggle switch and single pole light switch - Answers The toggle
switch has HP, voltage and amp ratings and also hp rated contacts. Is also able to interrupt locked rotor
current
