Chapter 05 - Components-Symbols and Circuitry of Air Conditioning Wiring Diagrams

What is a load?

Electrical devices that consume electricity to do useful work

What are some examples of loads?

Motors, Solenoids, resistance heaters

What are motors?

Electrical devices that consume electric energy to rotate a device

What are some items that use motors?

Compressors, Condenser and evaporator fan motors, pumps

What is the largest and most important type of loads?

Motors

What are solenoids?

Devices that create a magnetic field when energized. Causes some action to an electric component

What are some items that use solenoids?

Relays and contactors, valves

What are electric resistance heaters?

Convert electrical energy to heat

Do electric resistance heaters heat small or large areas?

Both

What are signal lights?

Lights are illuminated to denote a certain condition in a system

What are the three parts of contactors and relays?

Contact, coil or solenoid, mechanical linkage

Label

Left top: Armature

Left bottom: Coil

Right: Contact

What does this mean (contactor and relays)?

Normally open contact

What does this mean (contactor and relays)?

Normally closed co

What does normally open mean (contactors and relays)?

Contact is closed when coil is energized

What does normally closed mean (contacts and relays)?

Contact is opened when coil is energized

What electrical device is represented by this?

Three pole contactor

Magnetic starters provides both control and _____________ for electric motor circuits.

What do switches do?

Open and close to control loads in electrical circuits

Switches can be opened and closed by

Temperature, pressure, humidity, flow, manually

What is a pole (switches)?

Describes the number of contacts

What is a throw (switches)?

Tells how many positions each contact has

What is a disconnect switch used for?

Used to open and close main power source to equipment

Is a disconnect switch manual or automatic?

Manual

What is this?

Three pole fusible disconnect switch

What are thermostats?

Mechanically operated switched used in many control systems. Operated by temperature sensing element 

Cooling _______(closes or opens) on temperature rise

Closes

Heating _______(closes or opens) on temperature rise

Opens

What are pressure switches?

Control circuit based upon pressure. Used for different functions in HVAC/R systems

What are push button switched?

Open or closes contacts by pushing button

What are push button switches often used with?

Magnetic starters

What are fuses most effective aginst?

Large overload, less effective against small overload

How many times can a fuse be used?

Once

What is a thermal overload operated by?

Heat

What are examples of thermal overloads?

Pilot duty device and bimetal element

What does magnetic overload do?

Protects against high current draw. Operated by magnetism

What are these an example of?

Thermal overload

What are these an example of?

Fuses

What is this an example of?

Magnetic overload

What is this an example of?

Transformers

Transformers are used to supply how many volts to air conditioning control circuits 

24

Transformers are electrical devices used to

Increase or decrease the incoming voltage to a desired voltage

Which of the following choices best describes schematic wiring diagrams?

a. Schematic diagrams show physical location of components in a system.

b. Schematic diagrams show a circuit-by-circuit representation of how, when, and why a system works as it does.

c. Schematic diagrams show color coding, wire sizing, and terminal location to aid equipment installers.

d. Schematic diagrams show how and where each wire is connected within the equipment as well as wire color coding.

b. Schematic diagrams show a circuit-by-circuit representation of how, when, and why a system works as it does.

What’s another name for pictorial diagrams?

label or line diagrams

What’s a factual diagram?

Pictorial diagram with a schematic diagram

Why are factual diagrams used?

Helps technician locate components in equipment

What type of wiring diagram shows the technician how the actual internal wiring of the unit is connected?

Pictorial diagram

Why are installation diagrams used?

used to help the installation electrician 

Installation diagrams give information that is needed to make proper field wiring connections to equipment, including __________

a. Wire sizing information

b. Overcurrent protection (breakers and fuses) sizing information

c. Terminal designations and color coding

d. All of the choices are correct

d. All of the choices are correct