Motor Controls Practice Exam 3 with
Answers
Timers that can be set for multiple functions or as off-delay timers generally plug into
____-pin tube sockets - correct answer-11
Another name for a schematic diagram is a wiring diagram. - correct answer-False
The NEC® requires that each phase of a motor be protected by an overload relay. -
correct answer-True
A control relay is an electrically operated switch. - correct answer-True
How many wires are required for a two-wire control device? - correct answer-2
Relays are used more often to open and close control circuits than to operate power
circuits. - correct answer-True
Fuses and Circuit Breakers are used for short circuit protection. - correct answer-True
How is a change in the direction of rotation of a three-phase motor accomplished? -
correct answer-By interchanging any two motor leads to the line.
If the available power is 480/277-3 phase, and the control circuit is wired from phase to
ground, what is the control voltage? _____ volts. - correct answer-277
What are the advantages of a mechanically held relay? - correct answer-1) The relay
need not be reset when the power returns.
2) It is absolutely quiet in operation.
3) The current is not continually applied to the coils of the relay, thus conserving energy.
4) The circuit continuity is maintained during a power failure.
The neutral wire can be_______. - correct answer-White or light grey.
Main or subassembly line conveyors use sequence control. - correct answer-True
Mechanical connections are shown with ___. - correct answer-Strait broken lines
If the HOA switch is set in the off position, ____ current can flow to the coil of the
starter. - correct answer-No
, If the available power is 208V-3 phase, and the control circuit is wired phase to phase,
what is the control voltage? _____ volts. - correct answer-208
A mechanical interlocking device is assembled at the factory ____ the forward and
reverse contactors. - correct answer-Between
The operation of each additional push-button control station is different from that of the
single push-button control in the basic three-wire circuit. - correct answer-False
Normally open switches are drawn with the movable contact above and touching the
stationary contact. - correct answer-False
24 volts is the most common control voltage used in an intrinsically safe system. -
correct answer-True
Pressing any stop button de-energizes the coil. - correct answer-True
The most standardized set of symbols in the U.S. is provided by the NEMA. - correct
answer-True
Reversing starters are available in ____ construction. - correct answer-Horizontal and
vertical
A reversing starter usually consists of two (2) contactors and two (2) overload relays. -
correct answer-False
Pilot lights are tested frequently to ensure operation. - correct answer-True
The symbol for a __ switch represents a bimetal helix. - correct answer-Temperature
Why will the blowout coil also operate on AC? - correct answer-Since the current
reverses simultaneously in the blowout coil and arc, the motor action (arc deflection)
occurs in the same direction.
Neither jogging nor inching prevent a holding circuit. - correct answer-False
When reading a schematic diagram? - correct answer-Are the control components
shown as they should be when the machine is turned off or de-energized?
The term interlocking is used generally when referring to motor controllers and control
stations that are ____ to provide control of production operations. - correct answer-
Interconnected
Sirens, horns, and loud buzzers may be used in production systems to call attention to
malfunctions. - correct answer-True
Answers
Timers that can be set for multiple functions or as off-delay timers generally plug into
____-pin tube sockets - correct answer-11
Another name for a schematic diagram is a wiring diagram. - correct answer-False
The NEC® requires that each phase of a motor be protected by an overload relay. -
correct answer-True
A control relay is an electrically operated switch. - correct answer-True
How many wires are required for a two-wire control device? - correct answer-2
Relays are used more often to open and close control circuits than to operate power
circuits. - correct answer-True
Fuses and Circuit Breakers are used for short circuit protection. - correct answer-True
How is a change in the direction of rotation of a three-phase motor accomplished? -
correct answer-By interchanging any two motor leads to the line.
If the available power is 480/277-3 phase, and the control circuit is wired from phase to
ground, what is the control voltage? _____ volts. - correct answer-277
What are the advantages of a mechanically held relay? - correct answer-1) The relay
need not be reset when the power returns.
2) It is absolutely quiet in operation.
3) The current is not continually applied to the coils of the relay, thus conserving energy.
4) The circuit continuity is maintained during a power failure.
The neutral wire can be_______. - correct answer-White or light grey.
Main or subassembly line conveyors use sequence control. - correct answer-True
Mechanical connections are shown with ___. - correct answer-Strait broken lines
If the HOA switch is set in the off position, ____ current can flow to the coil of the
starter. - correct answer-No
, If the available power is 208V-3 phase, and the control circuit is wired phase to phase,
what is the control voltage? _____ volts. - correct answer-208
A mechanical interlocking device is assembled at the factory ____ the forward and
reverse contactors. - correct answer-Between
The operation of each additional push-button control station is different from that of the
single push-button control in the basic three-wire circuit. - correct answer-False
Normally open switches are drawn with the movable contact above and touching the
stationary contact. - correct answer-False
24 volts is the most common control voltage used in an intrinsically safe system. -
correct answer-True
Pressing any stop button de-energizes the coil. - correct answer-True
The most standardized set of symbols in the U.S. is provided by the NEMA. - correct
answer-True
Reversing starters are available in ____ construction. - correct answer-Horizontal and
vertical
A reversing starter usually consists of two (2) contactors and two (2) overload relays. -
correct answer-False
Pilot lights are tested frequently to ensure operation. - correct answer-True
The symbol for a __ switch represents a bimetal helix. - correct answer-Temperature
Why will the blowout coil also operate on AC? - correct answer-Since the current
reverses simultaneously in the blowout coil and arc, the motor action (arc deflection)
occurs in the same direction.
Neither jogging nor inching prevent a holding circuit. - correct answer-False
When reading a schematic diagram? - correct answer-Are the control components
shown as they should be when the machine is turned off or de-energized?
The term interlocking is used generally when referring to motor controllers and control
stations that are ____ to provide control of production operations. - correct answer-
Interconnected
Sirens, horns, and loud buzzers may be used in production systems to call attention to
malfunctions. - correct answer-True
