Symbols and Wiring Diagrams: Electrical Loads

 Motors:

• Symbols: Common symbols represent various motors.
• Abbreviations: Letters indicate the type of motor.
• Examples:
  • Compressor symbols
  • Evaporator fan motors
  • Condenser fan motor
  • Indoor fan motor
• Symbols may show windings.

Solenoids:

• Definition: Current flowing through a coiled wire creates a magnetic field causing an action in a relay or valve.
• Symbol: Common symbol for a solenoid valve.
• Components: Coiled wire, plunger, and valve seat.
• Operation:
  • Energized coil pulls the plunger up, allowing fluid flow.
  • De-energized coil drops the plunger, stopping flow.

Electric Heaters:

• Function: Convert electrical energy to heat.
• Symbol: Typical symbol for electric resistance heaters.
• Examples:
  • Crankcase heater: Prevents refrigerant migration and flooding starts on compressors.
  • Auxiliary strip heater: Found in electric furnaces or as backup heat on heat pumps.

Indicator Lights:

• Purpose: Show operation status or problems in circuits.
• Symbol: Designation indicates bulb color (e.g., R for red, B for blue, G for green).
• Circuit boards: May have multiple lights with different colors.