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

Thyristors

Solid-state relays

Solid-state overload relays

Timing relays

Question 1 of 25

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

decreases as the speed increases

is the square of the speed

increases as the speed increases

remains the same as the speed increases

Question 2 of 25

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 3 of 25

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

isolated solid-state relay

electromechanical relay

adjustable frequency drive

insulated gate bipolar transistor

Question 4 of 25

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

solenoid-operated friction brakes are engaged

the motor is stopped very gradually

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

it can be used to hold a suspended load

Question 5 of 25

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

100%

80%

150%

125%

Question 6 of 25

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

Controlled starting

Adjustable torque limiting

Adjustable operating speed

Reduced problems with harmonics and EMI

Question 7 of 25

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 B

A to C

A to D

Question 8 of 25

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

Analog switching

Zero switching

Peak switching

Instant on

Question 9 of 25

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

low initial cost

resistance to effects of temperature

response time

ability to stand surge currents

Question 10 of 25

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

NCTO contact

NOTC contact

NCTC contact

NOTO contact

Question 11 of 25

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

Kick-start controllers

Smooth-start controllers

Soft-start controllers

Boost-start controllers

Question 12 of 25

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

15%

10%

25%

Question 13 of 25

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

increased heat generated in motor windings

insufficient contact pressure

contactor freezing

rapid jogging

Question 14 of 25

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

peak mode

delayed normally open mode

delay-on-break mode

instant-on mode

Question 15 of 25

16.

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

wye-delta reduced-voltage starter

autotransformer reduced-voltage starter

part winding reduced-voltage starter

solid-state reduced-voltage starter

Question 16 of 25

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

a third of the minimum operating voltage for a single relay

four times the minimum operating voltage for a single relay

triple the minimum operating voltage for a single relay

half of the minimum operating voltage for a single relay

Question 17 of 25

18.

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

Question 18 of 25

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

Ability to stand surge currents

Faster response time

Arcless switching

Longer life expectancy

Question 19 of 25

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

a short circuit

sustained overload

a broken pole shader

a broken shading coil

Question 20 of 25

21. 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 energized

Before the relay is de-energized

Question 21 of 25

22.

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

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

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

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

Question 22 of 25

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

Class 10

Class 30

Class 40

Class 20

Question 23 of 25

24.

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

B to C

A to B

Question 24 of 25

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

Dynamic braking (DC electric braking)

Electromechanical braking

Dynamic braking (AC drives)

Static braking

Question 25 of 25

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