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For the AFD operating frequency range shown in the figure above, the range of output frequencies over which the AFD output voltage remains constant while the frequency varies is identified in the figure as ________.

A to C

A to B

B to C

Question 1 of 25

Which symbol in the figure above represents a normally open, timed-open (NOTO) contact of a timing relay?

Question 2 of 25

3. When does an off-delay relay provide the time delay?

After the relay is energized

After the relay is de-energized

Before the relay is de-energized

Before the relay is energized

Question 3 of 25

4. One advantage of DC electric braking is that ________.

the motor can be stopped without having to use brake linings or drums

the motor is stopped very gradually

solenoid-operated friction brakes are engaged

it can be used to hold a suspended load

Question 4 of 25

5. When three solid-state relays are connected in series, the supply voltage must be ________.

four times the minimum operating voltage for a single relay

half of the minimum operating voltage for a single relay

a third of the minimum operating voltage for a single relay

triple the minimum operating voltage for a single relay

Question 5 of 25

The circuit shown in the figure above is a(n) ________.

part winding reduced-voltage starter

wye-delta reduced-voltage starter

autotransformer reduced-voltage starter

solid-state reduced-voltage starter

Question 6 of 25

7. Which type of braking system engages solenoid-operated friction brakes?

Electromechanical braking

Dynamic braking (DC electric braking)

Static braking

Dynamic braking (AC drives)

Question 7 of 25

8. The voltage unbalance trip point for a programmable solid-state overload relay is typically set for ________.

25%

10%

15%

Question 8 of 25

The purpose of contactor 2M shown in the figure above is to ________.

energize motor leads T4, T5, and T6 during running to connect the motor windings in a delta configuration

connect resistors in series with the motor windings during the transition from start to run

energize motor leads T1, T2, and T3 for both wye and delta connections

short motor leads T4, T5, and T6 during starting to connect motor windings in a wye configuration

Question 9 of 25

10. When troubleshooting a motor, the possible cause for constant chatter is ________.

a short circuit

a broken shading coil

sustained overload

a broken pole shader

Question 10 of 25

11. Most NEMA-rated general purpose motors have an overcurrent trip class rating of ________.

Class 40

Class 10

Class 20

Class 30

Question 11 of 25

12. The 11-pin timing relay can be configured for single shot or ________.

instant-on mode

delayed normally open mode

peak mode

delay-on-break mode

Question 12 of 25

13. Which of the following solid-state relay switching modes are typically used to control heavy inductive loads?

Zero switching

Instant on

Peak switching

Analog switching

Question 13 of 25

14. Dynamic motor braking is often used with AC motors being controlled by a(n) ________.

adjustable frequency drive

isolated solid-state relay

insulated gate bipolar transistor

electromechanical relay

Question 14 of 25

15. Which of the following protect the motor and control devices against overheating?

Thyristors

Solid-state overload relays

Solid-state relays

Timing relays

Question 15 of 25

16. Which of the following characteristics are an advantage for using an electromechanical relay versus a solid-state relay?

Ability to stand surge currents

Arcless switching

Faster response time

Longer life expectancy

Question 16 of 25

17. An SSOLR initiates a trip if the phase currents exceed what percentage of the trip current dial setting?

100%

80%

150%

125%

Question 17 of 25

18.

The contactor sequence for the circuit shown in the figure above is such that during the transition from reduced-voltage operation to full-voltage operation, the energized contactors are 2S and ________.

Question 18 of 25

19. One of the advantages of an SSR over an EMR is its ________.

ability to stand surge currents

resistance to effects of temperature

low initial cost

response time

Question 19 of 25

20. Which of the following is a benefit derived from using a pulsewidth-modulated (PWM) adjustable frequency drive (AFD) versus an analog SCR AFD?

Adjustable operating speed

Adjustable torque limiting

Controlled starting

Reduced problems with harmonics and EMI

Question 20 of 25

21. What is another name given to solid-state, reduced-voltage starters because of their ability to provide a smoother, stepless start and acceleration?

Soft-start controllers

Smooth-start controllers

Kick-start controllers

Boost-start controllers

Question 21 of 25

22.

For the AFD operating frequency range shown in the figure above, the range of AFD output frequencies over which the ratio of volts to hertz remains constant is identified in the figure as ________.

A to C

A to B

A to D

Question 22 of 25

23. In a constant horsepower load, the torque ________.

remains the same as the speed increases

decreases as the speed increases

is the square of the speed

increases as the speed increases

Question 23 of 25

24. In a typical DC electric braking circuit, power is supplied to the braking relay by a(n) ________.

NCTC contact

NOTC contact

NOTO contact

NCTO contact

Question 24 of 25

25. A small unbalance in phase-to-phase voltage can result in ________.

contactor freezing

rapid jogging

insufficient contact pressure

increased heat generated in motor windings

Question 25 of 25

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