Question 1

There is a possibility of injury to an operator when the power suddenly resumes after a voltage failure.

Accepted Answer

When power suddenly resumes after a voltage failure, there is a surge of electricity that can potentially cause harm to an operator or anyone in contact with electrical equipment. It is important to follow proper lockout/tagout procedures and wait until it is safe to resume work. When power suddenly resumes after a voltage failure, machinery or equipment can start up without warning, potentially causing harm to an operator who may be working on or near it. It is important to follow proper safety procedures and protocols when working with machinery to prevent such injuries.

Question 2

With three-wire control, each time a voltage failure occurs the motors .&#10;A)restart automatically after a factory-set time lapse&#10;B)restart automatically after they cool down&#10;C)must be restarted manually&#10;D)restart automatically after an operator-set time lapse

Accepted Answer

With three-wire control, there is no automatic restart feature after a voltage failure. The motors must be restarted manually. With three-wire control, the motors must be restarted manually each time a voltage failure occurs.

Question 3

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 .&#10;A)solenoid&#10;B)transformer&#10;C)amplifier&#10;D)photocell

Accepted Answer

A control transformer is used to step down the voltage to a lower level suitable for the control circuit, which is necessary for the operation of the low-voltage release device.

Question 4

One method of preventing motor restart is known as .&#10;A)spike control&#10;B)high-voltage protection&#10;C)two-wire control&#10;D)low-voltage protection

Accepted Answer

Low-voltage protection prevents motor restart by ensuring that if the voltage drops below a certain level, the motor will not automatically restart when the voltage returns to normal. This requires manual intervention to restart the motor, enhancing safety.

Question 5

Restarting motors manually can cause damage to material in process or production.

Accepted Answer

Restarting a motor manually can cause sudden jerks or changes in speed which can cause damage to the material being processed or produced. It is recommended to use automatic restart methods to prevent such damages. Restarting motors manually can cause sudden jolts or movements in the material or machinery, leading to damage to the product in process or production. It is recommended to use automated systems or controlled procedures for restarting motors to prevent such damage.

Question 6

It is desirable to provide some means of automatically restarting motors after voltage failures.

Accepted Answer

Automatically restarting motors after voltage failures can be dangerous because it might lead to unexpected machinery operation, risking damage to the system or injury to personnel. It's important to assess the situation and ensure safety before restarting.

Question 7

To have the motor restart automatically, the operator will press the start button.

Accepted Answer

Pressing the start button initiates the motor's operation, but automatic restarts typically involve specific control settings or systems designed to resume operation after a stoppage without manual intervention.

Question 8

The use of a time-delay, low-voltage release device provides the safety of .&#10;A)spike control&#10;B)high-voltage protection&#10;C)three-wire control&#10;D)two-wire control

Accepted Answer

The answer of The use of a time-delay, low-voltage release...

Question 9

If the voltage failure exceeds the time-delay setting of the low-voltage release device, the motor .&#10;A)will not restart automatically&#10;B)may suffer severe damage&#10;C)will still restart automatically&#10;D)may suffer a slight damage

Accepted Answer

When the voltage failure exceeds the time-delay setting of the low-voltage release device, the motor will not restart automatically. This is a safety feature to prevent damage or unsafe conditions that might occur if power is restored unexpectedly.

Question 10

Three-wire control is impractical for preventing motor restart because momentary line voltage fluctuations occur in many localities.

Accepted Answer

Three-wire control only provides basic start and stop functionality and does not provide any protection against momentary voltage fluctuations that could cause motor restart. Therefore, it is impractical for preventing motor restart in many localities. Three-wire control relies on maintaining a continuous circuit to prevent motor restart, but momentary line voltage fluctuations can break the circuit and allow the motor to restart unexpectedly. Therefore, it is impractical for preventing motor restart in many localities.

Deck 24: Time-Delay Low-Voltage Release Relay