Question 1

AC relays used shading coils on the ____ to prevent contact chatter.&#10;A) iron core&#10;B) multi-core&#10;C) C-core&#10;D) bubble core

Accepted Answer

Shading coils are used to prevent contact chatter in AC relays by creating a flux path that is stronger in one direction than the other, keeping the contacts closed. This is done by using an iron core, which provides a high permeability path for the flux. The other options (B, C, and D) are not commonly used in AC relays.

Question 2

The term relay is often used to describe any type of electronically operated switch.

Accepted Answer

False

Question 3

Interlocking is used to cause some function to happen before some other function occurs.

Accepted Answer

False

Question 4

A solenoid is an electrical device that converts electrical energy to ____.&#10;A) regular motion&#10;B) linear motion&#10;C) curved motion&#10;D) vertical motion

Accepted Answer

A solenoid is an electromechanical device that generates a linear motion or force when an electric current is applied to it. This is accomplished through the electromagnetic interaction between the solenoid's wire coil and an iron core, which produces a magnetic field. This magnetic field causes the core to move linearly, either towards or away from the coil, depending on the direction of the current. Therefore, the best choice is B, linear motion.

Question 5

Eddy currents are currents induced in the core material by the magnetic field of the coil.

Accepted Answer

Eddy currents are indeed currents induced in the core material by the magnetic field of the coil.

Question 6

The plunger-type of solenoid is generally used with relays that use ____.&#10;A) complementary contacts&#10;B) double-break contacts&#10;C) auxiliary contacts&#10;D) load contacts

Accepted Answer

The plunger-type of solenoid is designed to work well with double-break contacts, which provide a reliable and consistent connection. Complementary, auxiliary, and load contacts may also be used in conjunction with relays, but they do not necessarily require a plunger-type solenoid to function effectively.

Question 7

Motor starters generally contain auxiliary contacts as well as ____.&#10;A) complementary contacts&#10;B) double-break contacts&#10;C) elementary contacts&#10;D) load contacts

Accepted Answer

Motor starters generally contain load contacts which are used to control the power supply to the motor. The auxiliary contacts are used for other purposes such as signaling or interlocking, but they are not an essential component of the starter itself. Complementary contacts and double-break contacts are specific types of contacts that may be used in a motor starter, but they are not a general feature of all starters. Elementary contacts are not a term commonly used in relation to motor starters.

Question 8

The relay operates on the solenoid principle.

Accepted Answer

Relays have a solenoid which when energized, generates a magnetic field that moves the armature and changes the contact position, thereby allowing or blocking the flow of current in a circuit.

Question 9

The advantage of the relay is ____.&#10;A) time&#10;B) power&#10;C) control&#10;D) size

Accepted Answer

The advantage of the relay is control. Relays are electromagnetically operated switches that are used to control circuits that carry high voltage or current levels, or both. They provide an isolation between the controlling circuit and the controlled circuit, which enhances safety and control.

Question 10

The relay is a magnetically operated switch.

Accepted Answer

A relay works by using an electromagnet to turn a switch on and off, making it a magnetically operated switch.

Deck 23: Relays, Contactors, and Motor Starters