1. There is a possibility of injury to an operator when the power suddenly resumes after a voltage failure.
a. True
b. False
2. It is desirable to provide some means of automatically restarting motors after voltage failures.
a. True
b. False
3. Three-wire control is impractical for preventing motor restart because momentary line voltage fluctuations occur in
many localities.
a. True
b. False
4. Restarting motors manually can cause damage to material in process or production.
a. True
b. False
5. To have the motor restart automatically, the operator will press the start button.
a. True
b. False
Name: Class: Date:
Unit 24 Time-Delay, Low-Voltage Release Relay
6. One method of preventing motor restart is known as ____.
a. spike control b. high-voltage protection
c. two-wire control d. low-voltage protection
7. With three-wire control, each time a voltage failure occurs the motors ____.
a. restart automatically after a factory-set time lapse
b. restart automatically after they cool down
c. must be restarted manually
d. restart automatically after an operator-set time lapse
8. If the voltage failure exceeds the time-delay setting of the low-voltage release device, the motor ____.
a. will not restart automatically b. may suffer severe damage
c. will still restart automatically d. may suffer a slight damage
9. The use of a time-delay, low-voltage release device provides the safety of ____.
a. spike control b. high-voltage protection
c. three-wire control d. two-wire control
10. The time-delay, low-voltage release device consists of a single-pole, normally open control relay, an electrolytic
capacitor, a rectifier, two resistors, and a control ____.
a. solenoid b. transformer
c. amplifier d. photocell
Name: Class: Date:
Unit 24 Time-Delay, Low-Voltage Release Relay