Course: HET 119 HVACR Electricity II

Lab Assignment

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Week 8 Lab Assignment: Electric Motors Controls – Relays, Overloads, and Capacitors

Recommended Materials
1. Lab Sheet
2. Pencil and paper
3. HVAC Textbook
4. Internet Search
5. Test Board 24” x 24”
6. Wires
7. Small hermetic compressor
8. Small Semi-hermetic compressor
9. Current Relay (Matched for the compressor)
10. Start Capacitor (Matched for the compressor)
11. Run Capacitor (Matched for the compressor)
12. Potential Relay (Matched for the compressor)
13. Compressor Overloads (Matched for the compressors)

Scope

This lab will help the student to learn how single phase motors and compressors operate with starting components. The student will wire and test motors components and safeties.

Procedures

1. The instructor will give you a diagram for a hermetic compressor with a current relay and start capacitor.
2. You will wire the hermetic compressor with a current relay and starting capacitor.
3. Have your instructor inspect your completed wiring.
4. Your instructor will give you approval to start and operate the compressor.
5. Record the amperage.
6. List all the data from the name plate.
7. Disassemble the hermetic compressor, components, and wiring.
8. Wire the semi-hermetic compressor with a start capacitor, run capacitor, and potential relay.
9. Have the instructor inspect your job.
10. Start the compressor and record the amperage, and voltage.
11. Wire the same semi-hermetic compressor without any capacitors.
12. Start the compressor and record the amperage, and voltage.
13. Disassemble the semi-hermetic compressor, components, and wiring.

Research Questions

1. What are the differences in these motors wiring?
2. How do you test a current relay with an Ohm-meter?
3. What was the difference in the volts and amperage readings from the semi-hermetic compressor with and without capacitors?
4. Why were there differences?
5. Explain how a potential relay operates.

Click on the file below to download the Lab Assignment
- HET 119 Wk 8 Lab.docx (15.61 KB)