313D Electrical Schematics and Controls 2

Question 1

In a ladder diagram, what does a normally closed (NC) contact symbol represent?

Accepted Answer

A contact that is closed during normal de-energized state

Answer

A contact that is open during normal de-energized state

Answer

A contact that only closes when power is applied

Answer

A contact that remains open regardless of coil state

Question 2

What is the purpose of a time-delay relay (TDR) in an AC system schematic?

Accepted Answer

To prevent short cycling by delaying compressor restart

Answer

To increase voltage to the compressor

Answer

To measure elapsed run time of the unit

Answer

To reduce current draw during startup

Question 3

On a wiring diagram, a dashed line connecting two components typically indicates:

Accepted Answer

A mechanical linkage or enclosed assembly boundary

Answer

A high-voltage connection

Answer

A ground wire

Answer

A future wiring connection

Question 4

Which control component in a residential AC system senses indoor temperature and signals the system to cycle on or off?

Accepted Answer

Thermostat

Answer

High-pressure switch

Answer

Contactor

Answer

Transformer

Question 5

A dual-voltage motor wired for 240V operation will have its internal windings connected in:

Accepted Answer

Series

Answer

Parallel

Answer

Delta configuration

Answer

Star configuration

Question 6

What does the symbol for a fuse look like on a standard electrical schematic?

Accepted Answer

A rectangle with a wavy line or S-curve inside

Answer

A circle with an X inside

Answer

Two parallel lines of unequal length

Answer

A triangle pointing upward

Question 7

In an AC control schematic, the R and C terminals on a thermostat typically represent:

Accepted Answer

Red wire and common ground for 24V control circuit

Answer

Return air and cooling mode signals

Answer

Reversing valve and compressor terminals

Answer

Resistor and capacitor components