Question 1

Which circuit is adjusted to detect certain levels of electrical interference or &#34;noise,&#34; and trips the drive in the event of a voltage sag, spike, or single phasing?&#10;A) Watchdog circuit&#10;B) Oscillator circuit&#10;C) Shunt field circuit&#10;D) Low-voltage logic circuit

Accepted Answer

Watchdog circuits are designed to monitor the operation of a system for malfunctions such as electrical noise, voltage sags, spikes, or single phasing, and can trigger a response, such as tripping the drive, to prevent damage or failure.

Question 2

The control section of a DC drive uses three types of signals to evaluate motor performance: the command, feedback, and ____ signals.&#10;A) set point&#10;B) reference&#10;C) error&#10;D) open-loop

Accepted Answer

Error signals are used in the control section of a DC drive to evaluate motor performance. They are generated by comparing the command signals (what the motor is instructed to do) with the feedback signals (what the motor is actually doing), thus identifying any discrepancy or error between the desired and actual performance.

Question 3

Mechanical vibration may loosen the mounting or alter the ____ of feedback devices.&#10;A) input&#10;B) alignment&#10;C) adjustment&#10;D) control

Accepted Answer

Mechanical vibration can cause the physical misalignment of feedback devices, affecting their accuracy and performance.

Question 4

A controller's ____ determines how well it responds to changes in motor performance and is usually expressed as a percentage.&#10;A) set point&#10;B) regulation&#10;C) efficiency&#10;D) feedback

Accepted Answer

A controller's regulation determines how well it responds to changes in motor performance, and it is typically expressed as a percentage. This term refers to the controller's ability to maintain a constant output despite variations in the input or other external conditions.

Question 5

If the motor doesn't run, the problem must be the drive.

Accepted Answer

The problem with a non-running motor could be due to various issues such as electrical connections, power supply, motor windings, or even control signals, not just the drive.

Question 6

Armature voltage control is the type most commonly used in DC drives.

Accepted Answer

Armature voltage control is the most commonly used method for controlling the speed of DC motors in DC drives because it provides a simple and effective means of speed control by varying the voltage applied to the motor's armature.

Question 7

Motor operation in quadrant ____ produces regenerative braking action when the motor turns in reverse.&#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

Accepted Answer

In quadrant 4, the motor operates in reverse direction while still producing torque in the same direction as the motion, which results in regenerative braking.

Question 8

Most drive failures occur in the ____ section, where you will find power SCRs, transistors, MOSFETs, and so on.&#10;A) power&#10;B) control&#10;C) feedback&#10;D) transistor

Accepted Answer

Most drive failures occur in the power section, which contains components like power SCRs, transistors, MOSFETs, that are prone to high stress and failure.

Question 9

The most common cause of motor failure is heat.

Accepted Answer

Heat is the most common cause of motor failure because it can degrade insulation and lead to winding failure, among other issues.

Question 10

In which quadrant of motor operation is the motor regenerating?&#10;A) Quadrant 1&#10;B) Quadrant 2&#10;C) Quadrant 3&#10;D) Quadrant 4

Accepted Answer

In Quadrant 2, the motor operates in the reverse direction while generating power, which is known as regenerative braking.

Question 11

In which quadrant of motor operation is the motor driving a load and turning in the forward direction?&#10;A) Quadrant 1&#10;B) Quadrant 2&#10;C) Quadrant 3&#10;D) Quadrant 4

Accepted Answer

The answer of In which quadrant of motor operation is...

Question 12

Open-loop control is also called automatic control.

Accepted Answer

The answer of Open-loop control is also called automatic control....

Question 13

A ____ is a circuit that uses very fast electronic switches.&#10;A) booster&#10;B) stepper&#10;C) modulator&#10;D) chopper

Accepted Answer

The answer of A ____ is a circuit that uses...

Question 14

An electronic variable speed drive has two basic sections: the control section and the power section.

Accepted Answer

The answer of An electronic variable speed drive has two...

Question 15

A command signal, sometimes called the ____ or reference signal, is programmed into the DC drive and sets the desired operating speed of a DC motor.&#10;A) steady state&#10;B) target&#10;C) set point&#10;D) encoder

Accepted Answer

The answer of A command signal, sometimes called the ____...

Deck 22: Dc Electronic Variable Speed Drives