Deck 22: Dc Electronic Variable Speed Drives

Question 1

Most drive failures occur in the ____ section, where you will find power SCRs, transistors, MOSFETs, and so on.

A) power
B) control
C) feedback
D) transistor

Answer 1

A

Question 2

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

Answer 2

True

Question 3

The control section of a DC drive uses three types of signals to evaluate motor performance: the command, feedback, and ____ signals.

A) set point
B) reference
C) error
D) open-loop

Answer 3

C

Question 4

A controller's ____ determines how well it responds to changes in motor performance and is usually expressed as a percentage.

A) set point
B) regulation
C) efficiency
D) feedback

Question 5

Motor operation in quadrant ____ produces regenerative braking action when the motor turns in reverse.

A) One
B) Two
C) Three
D) Four

Question 6

Which of the following can be adjusted to detect certain levels of electrical interference or "noise," and trips the drive in the event of a voltage sag, spike, or single phasing?

A) Watchdog circuit
B) MOSFET circuit
C) IR compensation circuit
D) Ramp rate circuit

Question 7

A(n) ____ is a circuit that uses very fast electronic switches.

A) booster
B) stepper
C) modulator
D) chopper

Question 8

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

Question 9

Open-loop control is also called automatic control.

Question 10

In which quadrant of motor operation is the motor regenerating?

A) One
B) Two
C) Three
D) Four

Question 11

The most common cause of motor failure is heat.

Question 12

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.

A) steady state
B) target
C) set point
D) continuous

Question 13

Mechanical vibration may loosen the mounting or alter the ____ of feedback devices.

A) input
B) alignment
C) adjustment
D) control

Question 14

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

Question 15

In which quadrant of motor operation is the motor motoring, or moving a load in the forward direction?

A) One
B) Two
C) Three
D) Four