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

insufficient contact pressure

contactor freezing

increased heat generated in motor windings

rapid jogging

Question 1 of 25

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

Thyristors

Timing relays

Solid-state relays

Solid-state overload relays

Question 2 of 25

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

sustained overload

a broken pole shader

a broken shading coil

a short circuit

Question 3 of 25

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

delay-on-break mode

peak mode

instant-on mode

delayed normally open mode

Question 4 of 25

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

150%

100%

80%

125%

Question 5 of 25

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

Class 30

Class 20

Class 10

Class 40

Question 6 of 25

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

After the relay is de-energized

Before the relay is de-energized

Before the relay is energized

After the relay is energized

Question 7 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 8 of 25

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 B

B to C

A to C

Question 9 of 25

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

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

solenoid-operated friction brakes are engaged

the motor is stopped very gradually

it can be used to hold a suspended load

Question 10 of 25

11. 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 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?

Smooth-start controllers

Boost-start controllers

Soft-start controllers

Kick-start controllers

Question 12 of 25

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

Electromechanical braking

Static braking

Dynamic braking (DC electric braking)

Dynamic braking (AC drives)

Question 13 of 25

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

NCTC contact

NOTO contact

NCTO contact

NOTC contact

Question 14 of 25

15.

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

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

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

Question 15 of 25

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

triple the minimum operating voltage for a single relay

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

Question 16 of 25

17.

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 D

A to B

Question 17 of 25

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

low initial cost

ability to stand surge currents

resistance to effects of temperature

response time

Question 18 of 25

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

15%

25%

10%

Question 19 of 25

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

Analog switching

Zero switching

Instant on

Peak switching

Question 20 of 25

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

is the square of the speed

remains the same as the speed increases

decreases as the speed increases

increases as the speed increases

Question 21 of 25

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

Faster response time

Ability to stand surge currents

Arcless switching

Longer life expectancy

Question 22 of 25

23.

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

autotransformer reduced-voltage starter

wye-delta reduced-voltage starter

solid-state reduced-voltage starter

part winding reduced-voltage starter

Question 23 of 25

24.

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

Question 24 of 25

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

insulated gate bipolar transistor

adjustable frequency drive

isolated solid-state relay

electromechanical relay

Question 25 of 25

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