1. Basic Electric 3 HVAC Electric Components

2. 4.2.1 Switches Single-pole, single-throw (SPST)
Double-pole, single-throw (DPST)
Double-pole, double-throw (DPDT)
INSTRUCTOR NOTES: Explain that these pole and throw arrangements also apply to relays.
Basic Electricity

3. Common Switch Applications
4.2.1
Common Switch Applications
Switches are used in many ways, even to respond to light or moisture.
INSTRUCTOR NOTES: Talk about the different ways thermostatic and pressure switches are used to control system functions.
Basic Electricity

4. 4.2.2
Circuit Breaker Panel
Special HACR circuit breakers are used for air conditioning equipment for the same reason that slow-blow fuses are used.
INSTRUCTOR NOTES: Explain the difference between magnetic- and thermal-trip circuit breakers.
Basic Electricity

5. 4.2.3
Solenoid
The operating coil of a solenoid valve essentially creates an electromagnet when it is energized.
Basic Electricity

6. 4.2.4
Control Relays
Contactors and motor starters are simply relays that control greater amounts of current and/or have additional features related to motor protection.
Basic Electricity

7. 4.2.5
Control Transformer
INSTRUCTOR NOTES: Discuss the different transformer forms and common applications. Explain how control transformers are rated.
Basic Electricity

8. 4.2.8
Electronic Controls
Printed circuit boards contain items such as miniature relays, terminals for wiring connections, resistors, diodes, and capacitors.
INSTRUCTOR NOTES: Discuss the applications of electronic controls. Explain that most boards are not field-repaired, but that technicians must determine if a failure was related to the board itself or to an external problem.
Basic Electricity