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

Q: DC drives give the DC motor which of the following characteristics?
- controlled acceleration and deceleration
- high starting horsepower
- high running horsepower
- good speed regulation
A: controlled acceleration and deceleration

Q: Fig #2
In fig #2 above, when the wiper arms of all three variable resistors are adjusted fully downward, the voltage at R2 is_________.
- 0V
- 5V
- 7.5V
- 15V
A: 0V

Q: Fig #3
In fig #3 above, the acceleration will be the slowest if the wiper arm of R12 is _______________.
- to the far right
- in the middle
- to the far left
A: to the far right

Q: Fig #4
In figure #4 above, when the start button is pressed, the N.O. CR contacts are closed and the current through the armature ___________.
- flows through the resistor
- is supplied through the motor control circuitry
A: flows through the resistor

Q: If the current applied to the armature of a shunt field type DC motor is constant and the current applied to the field coil is reduced, the motor speed will __________.
- increase
- decrease
- stay the same
A: increase

Q: In an application where the horsepower required by the load is constant, if the speed of a DC motor is reduced, the torque is __________.
- increased
- decreased
A: increased

Q: In fig #2 above, if the wiper arm of the high-speed rheostat is positioned at the middle of the resistor body and the low-speed rheostat is adjusted fully downward, which voltage range is most likely developed at the wiper arm of R2?
- 0 to +15V
- 0 to +12V
- +3 to +15V
A: 0 to +15V

Q: In fig #3 above, the function of R12 is to ______________.
- control the speed at which the capacitor charges
- control the voltage that develops on the top plate of the capacitor
- both a and b
A: control the speed at which the capacitor charges

Q: In the above figure, current flows through the field coil when either the start button or the stop button is pressed.
- True
- False
A: True

Q: In the figure above, the function of D5 and D6 are to _______________.
- provide rectification to the armature
- provide a pulsating DC voltage to the field coil
- both a and b
- provide a discharge path for the collapsing flux of the field coil
A: provide rectification to the armature

Q: In the figure above, the function of the SCRs is to _____________.
- provide rectification for the armature
- control the amount of current flow through the armature
- both a and b
- control the amount of current flow through the armature and the field coils
A: provide rectification for the armature

Q: Motor braking using both the dynamic and regenerative methods is accomplished by reversing the current through the armature.
- True
- False
A: True

Q: Reducing the field voltage ____________ the speed of the motor and _________ its torque.
- increases, decreases
- decreases, increases
- has no effect
A: increases, decreases

Q: The ___________ braking method uses a resistor to absorb kinetic energy from the rotating armature and load to stop the motor.
- dynamic
- regenerative
A: dynamic

Q: The effective operation of punch presses, high inertia machines, pumps, and centrifugal fans require __________ load characteristics.
- constant torque
- constant horsepower
- variable torque
A: constant torque

Q: The effective operation of conveyors, extruders, and hoists requires _________ load characteristics.
- constant torque
- constant horsepower
- variable torque
A: constant torque

Q: The speed of the DC motor that requires a constant torque is controlled by adjusting the ______________.
- field current and keeping the armature voltage constant
- armature voltage and keeping the field current constant
- armature voltage and the field current
A: field current and keeping the armature voltage constant

Q: Varying the voltage from the drive to the field of a motor is used to control which of the following variables?
- full speed range of the motor
- the velocity above the rated base speed of the motor
- constant torque
- acceleration and deceleration
A: full speed range of the motor

Q: Which of the following devices are not used as the operator control source for the DC drive?
- switches and pushbuttons
- keypads
- programmable controllers
- computers
A: switches and pushbuttons

Q: Which of the following types of DC motors are typically controlled by a DC drive?
- permanent magnet
- series
- shunt
- compound
- both a and c
A: permanent magnet