Title: AC Drives Test
Course: Basic of Motor Theory (IC 105-IC 105) > Section: Assessments

Q: _________ refers to braking by dissipating energy from the motor by a resistor.
- Regeneration
- Dynamic braking
A: Regeneration

Q: ___________ parameters are parameters that can be programmed or adjusted to set a drive for a specific application and motor.
- Display
- Editing
- Remote control
- Application control
A: Display

Q: _____________ parameters normally require technical information listed on a motor nameplate.
- Display
- Editing
- Basic programming
A: Display

Q: ______________ refers to braking by returning power back to the power line.
- Regeneration
- Dynamic braking
A: Regeneration

Q: A dynamic braking resistor in an AC drive is connected to the terminals of the _________.
- motor
- inverter section
- intermediate section
- converter
- AC power lines
A: motor

Q: A power loss ride through function is limited to __________ seconds.
- 1-2
- 5
- 10
- unlimited
A: 1-2

Q: A single-phase power supply voltage can be used for low horsepower AC drives.
- True
- False
A: True

Q: A(n) ___________ can be used to control the speed of a motor.
- potentiometer
- inverter
- magnetic motor starter
- converter
A: potentiometer

Q: AC motor drives are referred to as ____________ drives.
- variable-frequency
- inverter
- closed-loop
A: variable-frequency

Q: An auto boost circuit is activated if extra current is needed when ____________.
- the motor is starting
- the motor is running at low RPM
- both a and b
A: the motor is starting

Q: An auto boost is a function that helps overcome inertia.
- True
- False
A: True

Q: During starting, drives typically limit the inrush of current at motors to _________ percent.
- 80
- 100
- 150
- 600-700
A: 80

Q: If a microprocessor is used in an AC drive it is located in which section?
- converter
- intermediate
- inverter
- control circuit
A: converter

Q: If the synchronous speed produced by the drive is reduced by half and the voltage remains constant, the current through the motor will __________.
- reduce by one-fourth
- reduce by half
- double
- increase by four
A: reduce by one-fourth

Q: Increasing the frequency to a motor above ___________ Hz increases the noise produced by the motor.
- 20
- 40
- 60
- 80
A: 20

Q: One of the functions of the acceleration adjustment is to provide a starting speed of the motor that is quicker than if it was directly powered by the power line.
- True
- False
A: False

Q: Standard off-the-shelf induction motors become damaged primarily from ___________, when connected to an AC drive.
- overheating
- cogging at low speeds
- voltage spikes
- vibration
A: overheating

Q: The characteristics of both thyristors or IGBTs are compatible to the operation of a PWM-type drive.
- True
- False
A: False

Q: The control voltage of a motor drive is normally ________ VDC or _________VDC, which provides additional safety because of the low voltage.
- 10; 18
- 12; 24
- 20; 25
- 30; 36
A: 10; 18

Q: The converter section of an AC drive performs rectification.
- True
- False
A: True

Q: The DC bus line is the output of the intermediate section.
- True
- False
A: True

Q: The intermediate section of an AC drive performs the filtering function.
- True
- False
A: True

Q: The PWM drive that cannot be used to power several motors simultaneously is the ___________ type.
- volts/Hz
- AC closed-loop
- sensorless vector
- both b and c
A: volts/Hz

Q: The PWM drive varies its ____________ by changing the number of pulses and their widths.
- RMS voltage
- frequency
- both a and b
A: RMS voltage

Q: The section of an AC drive that converts AC power to a DC voltage is the __________.
- converter
- intermediate circuit
- inverter
- control circuit
A: converter

Q: The sensorless vector drive has no self-correcting capabilities.
- True
- False
A: False

Q: The term inverter refers to _____________.
- an AC drive
- the power output section of the AC drive
- both a and b
A: an AC drive

Q: The term overhauling used for AC drives refers to ______.
- the rebuilding of the motor it runs
- the rebuilding of the drive circuitry
- the load and motor turning faster than the synchronous speed
- the synchronous speed turning faster than the load
A: the rebuilding of the motor it runs

Q: The term used to describe the programming of a drive so that it avoids running within a harmful speed range is _______.
- speed compensation
- critical frequency rejection
- skip frequency
- both b and c
A: speed compensation

Q: To maintain a desired V/Hz ratio when increasing the speed of a motor, the AC drive must __________.
- increase its output frequency
- increase its voltage
- both a and b
A: increase its output frequency

Q: Under which of the following conditions will an overcurrent condition develop in an AC drive?
- The physical load the motor is driving becomes excessive.
- The starting inertia of the load is too high and the acceleration time is too short.
- A short develops in the motor winding.
- A component in the inverter section shorts.
A: The physical load the motor is driving becomes excessive.

Q: What kind of AC motor is most frequently driven by an AC drive?
- synchronous
- squirrel-cage induction
- split-phase
A: synchronous

Q: When a vector drive holds the motor in a stationary position, the stator flux ____________.
- is turned on and off at a rapid rate of speed
- is held constant
- lines are alternated in opposite directions at a high rate of speed
A: is turned on and off at a rapid rate of speed

Q: Which function is performed by the diodes placed across the semiconductor switches in the inverter?
- protects the semiconductor from a voltage spike
- provides a path for current when regeneration occurs
- both a and b
A: protects the semiconductor from a voltage spike

Q: Which of the following functions are performed by the intermediate section in various AC drives?
- filters DC pulsations from the converter
- varies the DC bus line voltage
- both a and b
A: filters DC pulsations from the converter