Question 1

Give an overview of how a relay-based low-voltage remote-control system operates.

Accepted Answer

A low-voltage remote-control wiring system is relay operated. The relay is controlled by a low-voltage switching system and in turn controls the power circuit connected to it. The low-voltage, split-coil relay is the heart of the low-voltage remote-control system. When the "On" coil of the relay is energized, the solenoid mechanism causes the contacts to move into the "On" position to complete the power circuit. The contacts stay in this position until the "Off " coil is energized. When this occurs, the contacts are withdrawn and the power circuit is opened. The red wire is the "On" wire; the black wire is "Off "; and the blue wire is common to the transformer.

Question 2

When are low-voltage remote-control systems advantageous?

Accepted Answer

Low-voltage remote control systems are chosen because of the number of switches required and when it is desired to have extensive control of the lighting. Low-voltage remote-control systems are available ranging from very simple to very complex. These systems can provide control from multiple locations, automatic timing control, handheld (wireless)controls, occupancy sensors ("On" when motion is detected)and unoccupancy sensors ("Off " with predetermined time-delay when no one is in the room), ceiling and wall mounted sensors, photocell control for security ("On" at dusk, "Off " at dawn), and programmable controls. Federally mandated energy codes are an energy standard for buildings, such as the joint publication ANSI/ASHRAE/IESNA 90.1, the most widely adopted energy standard

Question 3

A low-voltage remote-control wiring system is ____ operated.

Accepted Answer

Low-voltage remote-control wiring systems are typically relay operated, as relays are used to switch the system on and off or to control various functions remotely, using low voltage signals.

Question 4

If control requirements are very complex or extensive, a ____ can be installed.

Accepted Answer

A master sequencer is designed to handle complex or extensive control requirements by coordinating and managing multiple processes or operations in a systematic manner.

Question 5

In a Class 2 circuit, because the power source of the circuit is limited, ____ overcurrent protection is required.

Accepted Answer

In a Class 2 circuit, the power source itself is limited to prevent high currents, so no additional overcurrent protection is required.

Question 6

The ____ is used in an installation where several relays are mounted in one enclosure.

Accepted Answer

Plug-in relays are designed for easy installation and removal from a base or socket, making them suitable for applications where multiple relays are mounted in one enclosure for ease of maintenance and replacement.

Question 7

What size knockout openings can relays be mounted through? What advantage does the plug-in relay have?

Accepted Answer

The answer of What size knockout openings can relays be...

Question 8

What happens to a transformer in the case of an overload?

Accepted Answer

The answer of What happens to a transformer in the...

Question 9

To install color-coded cables correctly throughout an entire installation, the wires are connected to the ____, switches, master controls, and panel, like color to like color.

Accepted Answer

Relays are devices used in electrical systems to control circuits, often used in conjunction with color-coded cables for easy identification and correct installation.

Question 10

The switch used in the low-voltage remote-control system is a normally open, ____, momentary contact switch.

Accepted Answer

The answer of The switch used in the low-voltage remote-control...

Question 11

____ identifying the switch's functions can be prepared and inserted in the switch cover.

Accepted Answer

Directory strips are used for identifying the switch's functions and can be inserted in the switch cover. These strips often have labels or instructions that indicate what each switch controls, making it easier for users to understand their functions.

Question 12

The principle of operation of a master control with rectifiers is based on the fact that a rectifier permits current in ____ direction(s).

Accepted Answer

Rectifiers are electronic devices that convert alternating current (AC) to direct current (DC), allowing current to flow in only one direction.

Question 13

The low-voltage relay is available in ____ mounting styles.

Accepted Answer

Low-voltage relays are available in two mounting styles: panel mount and DIN rail mount.

Question 14

The switch used in the low-voltage remote-control system is approximately ____ the size of a standard single-pole switch.

Accepted Answer

The switch used in the low-voltage remote-control system is approximately one-third the size of a standard single-pole switch.

Question 15

Larger conductors should be used for long runs to minimize the ____.

Accepted Answer

Larger conductors are used for long runs to minimize the voltage drop across the length of the conductor. This ensures that electrical devices receive sufficient voltage to operate effectively.

Question 16

NEC 725.136 ( A )generally ____ Class 2 circuits in the same raceway or cable as the wiring for light and power.

Accepted Answer

The National Electrical Code (NEC) prohibits mixing Class 2 circuits with the wiring for light and power in the same raceway or cable.

Question 17

Switches are available in up to ____-switch combinations with features such as pilot light, lighted toggle, and key operation.

Accepted Answer

Switches can be found in up to 8-switch combinations, accommodating various features like pilot lights, lighted toggles, and key operations. This allows for a wide range of control and customization in electrical systems.

Question 18

Most low-voltage, remote-control systems are wired with ____ AWG conductors.

Accepted Answer

Most low-voltage, remote-control systems use 20 AWG conductors due to their sufficient capacity for the low current requirements of these systems, balancing efficiency and cost.

Question 19

Give one advantage and one disadvantage to installing low-voltage wiring in a raceway.

Accepted Answer

The answer of Give one advantage and one disadvantage to...

Question 20

To simplify connections, the conductor color-coding combinations are red-black-white, red-black-yellow-white, red-black-yellow plus an 18 AWG common ____, red-black-blue-white, and red-black-yellow-blue-white.

Accepted Answer

The answer of To simplify connections, the conductor color-coding combinations...

Quiz 20: Low-Voltage Remote Control