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c. either a or b
A DC drive can be powered from ___ power supply. Select one: a. a DC b. an AC c. either a or b d. neither a nor b
b. torque
A DC drive controls the ___ of a DC motor by varying the current applied to the armature. Select one: a. rotational speed b. torque
b. rotational speed
A DC drive controls the ___ of a DC motor by varying the voltage applied to the armature. Select one: a. torque b. rotational speed
b. any of these
A fault code displayed on a motor drive could indicate a(n) ___. Select one: a. loss of phase b. any of these c. undervoltage condition d. drive overload
a. True
A reduction in energy consumption can also be realized by reducing the speed of electric motors. Select one: a. True b. False
b. converter
A(n) ___ changes AC voltage into DC voltage. Select one: a. inverter b. converter
a. inverter
A(n) ___ changes DC voltage into AC voltage. Select one: a. inverter b. converter
d. all of these
Although most motor drive parameters are factory programmed, motor ___ is a parameter that has to be reprogrammed for the specific installation. Select one: a. nameplate current b. stopping mode c. acceleration time d. all of these
d. all of these
An AC drive contains a(n) ___. Select one: a. converter b. DC bus c. inverter d. all of these
b. frequency
An AC drive controls the rotational speed of an AC motor by varying the ___ applied to the motor. Select one: a. voltage b. frequency
a. adjustable frequency
An AC motor drive is also referred to as a(n) ___ drive. Select one: a. adjustable frequency b. converter c. open loop d. any of these
d. any of these
An AC motor drive is also referred to as a(n) ___ drive. Select one: a. variable frequency b. inverter c. direct torque control d. any of these
c. 3
An AC motor drive is underpowered and/or overloaded when the difference in full-load voltage and no-load voltage at the drive's output terminals is greater than ___%. Select one: a. 10 b. 1 c. 3 d. 5
a. surge-suppression
An MOV connected across the input terminals of an AC drive provides ___ protection to the drive. Select one: a. surge-suppression b. overload c. ground-fault d. all of these
e. all of these
Both AC and DC motor drives are used to control the ___ of a motor. Select one: a. speed b. direction of rotation c. accelerating times d. decelerating times e. all of these
c. either a or b
Except emergency stops, a motor ___ should be used for plugging applications. Select one: a. designated for plugging b. with a SF of 1.35 or greater c. either a or b d. neither a nor b
a. decrease
For a constant horsepower/variable torque (CH/VT) load, an increase in operating speed requires a(n) ___ in torque. Select one: a. decrease b. increase
c. either a or b
For a motor drive the control and drive functions are controlled by ___. Select one: a. keypad inputs b. switch settings c. either a or b d. neither a nor b
c. both a and b
For a variable torque/variable horsepower (VT/VH) load, an increase in operating speed requires an increase in ___. Select one: a. horsepower b. torque c. both a and b d. neither a nor b
d. I, II & III
For electrical braking circuits, ___ interlocking should always be used. I. electrical II. mechanical III. pushbutton Select one: a. I & II only b. II only c. III only d. I, II & III e. I only f. I & III only
d. solenoid
Friction braking of a motor is normally controlled by a(n) ___. Select one: a. MOV b. transformer c. pushbutton d. solenoid
d. dynamic
Immediately after being turned off, ___ braking of a motor involves the reconnection of the motor to act as a generator. Select one: a. reactive b. friction c. electric d. dynamic
c. off-delay
In DC electric braking circuits, a(n) ___ timing relay is used to stop motor. Select one: a. one-shot b. recycle c. off-delay d. on-delay
c. both a and b
Motor drives provide energy savings when used with ___ and loads. Select one: a. variable-torque b. variable-speed c. both a and b d. neither a nor b
c. either a or b
Small drives controlling 3Ø motors can be supplied with ___ power. Select one: a. 1Ø b. 3Ø c. either a or b d. neither a nor b
a. constant
The LOAD switch on a drive is set to CT for ___-torque loads. Select one: a. constant b. variable
a. variable
The LOAD switch on a drive is set to P&F for ___-torque loads. Select one: a. variable b. constant
varies b. maintain proper voltage levels when voltage fluctuates
The main function of capacitors in the DC bus of an AC motor drive is to ___. Select one: a. adjust the motor speed when the load varies b. maintain proper voltage levels when voltage fluctuates c. provide for frequency adjustments d. all of these
c. generator
When coasting to a stop after the power has been removed from a DC motor, the motor acts as a ___. Select one: a. transformer b. drive c. generator d. none of these
e. any of these
When operating at different speeds, a motor may be required to deliver ___ to a driven load. Select one: a. variable torque b. variable horsepower c. constant horsepower d. constant torque e. any of these
d. any of these
Which of the following is a braking method used for a motor? Select one: a. friction b. dynamic c. plugging d. any of these e. none of these
c. both a and b
___ affect the time required for a motor to come to a stop. Select one: a. Friction b. The inertia of the motor and its load c. both a and b d. neither a nor b
c. Electric
___ braking of a motor involves the application of a DC voltage to the windings of an AC motor after AC power is removed. Select one: a. Dynamic b. Reactive c. Electric d. Friction
e. II & III only
___ can be used to bring a motor to a complete stop. I. Dynamic braking II. Plugging III. Friction braking Select one: a. III only b. I & III only c. I, II & III d. I only e. II & III only f. II only
c. both a and b
___ cause high-energy-level transient voltages. Select one: a. Utility switching b. Lightning strikes c. both a and b d. neither a nor b
c. Plugging
___ is the reversing of motor connections to develop a counter-torque that will rapidly stop the motor's rotation, thus serving as a braking method. Select one: a. Sequencing b. Jogging c. Plugging d. None of these