Schematic Wiring and Components Lecture

Overview

• Focus: Creating a new wiring schematic involving switches, transformers, fuses, and relays.
• Goal: To understand the wiring process from high voltage components to low voltage components and how they interact.

Schematic Breakdown

High Voltage Circuit

1. Line 1 to Switch
   • Connect Line 1 to a fan relay switch.
   • Identify terminals: normally open and closed.
   • Use terminal 3 (normally open) to terminal 1 (normally open) to control the fan motor.
2. Fan Motor Connection
   • Line 1 connects to the fan motor via terminal 1.
   • Output from the fan motor returns to Line 2, completing a high voltage circuit.
3. Transformer Use
   • Line 1 also connects to a transformer.
   • Common wire (white) used for identification.
   • Line 2 connection made through a black wire, which denotes 115 volts.

Low Voltage Circuit

1. Transformer to Fuse
   • Low voltage exits transformer into a fuse.
   • AC current allows flexibility in wire choice.
2. Fuse to Switch
   • From fuse to R terminal of a switch.
   • From switch to G terminal, which connects to a low voltage load.
3. G Terminal and Fan Relay
   • G terminal connects to low voltage fan relay.
   • Ensure connection to 24-volt common for circuit completion.

Operational Explanation

• Power Up: Switching on powers the low voltage circuit first.
  • Closing the switch energizes the fan relay’s electromagnet.
  • Energized electromagnet closes high voltage contacts.
  • High voltage contacts power the fan motor, activating it.

Thermostat Operation

• Fan Control: Adjusting the thermostat to "fan on" uses the same principle.
  • R and G terminals connect, energizing the fan relay coil.
  • High voltage fan motor activates through relay contact closure.

Additional Insights

• Component Flexibility: Understanding how to identify components and their terminals is crucial for HVAC work.
• System Changes: The lecture suggests making further modifications and understanding circuit flexibility.
• Safety: Emphasis on turning off power and ensuring safe wiring practices.

Practical Tips

• Observation: Take time to analyze unfamiliar components.
• Innovation: Use system knowledge to adapt to new setups or changes.
• Careful Wiring: Highlighting wires and ensuring clear labeling is crucial for functionality and safety.

Conclusion

• The lecture emphasizes understanding the relationship between low and high voltage components and how they interact to operate HVAC systems effectively.