Course: HET 119 HVACR Electricity II

Lab Assignment

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Week 13 Lab Assignment: Three Phase Motors and Control Devices

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 HP 3 Phase Motor
8. Motor Starter
9. Push Button Off and On switch
10. 1 Light bulb and fixture (The lights will be used for the remote indicator light)
11. Jumper wires

Scope

This lab will help the student to understand Control Devices and how it is used in electrical circuits in refrigeration systems. The student will wire controls to loads in combination circuits.

Procedures

1. Follow the diagram posted and wire the motor to a Wye windings and have your instructor inspect.
2. Measure the resistance of the windings of the wye windings and record.
3. Wire the same motor to Delta windings and have your instructor inspect.
4. Measure the resistance of the windings of the delta windings and record.
5. On a test board, wire a circuit as a three phase motor with a motor starter and remote bulb as an indicator.
6. Have the instructor specify the controls you will need for this assignment.
7. Have the instructor to inspect the circuit.
8. Press the push button to the on position and witness the action.
9. Explain what is the purpose of these controls:
  1. Magnetic Motor Starter
  2. Heaters
  3. Two Position  Push Button Switch
  4. Wye Windings
  5. Delta Windings
  6. Auxiliary Switch

Motor Starter Controls

Research Questions

1. What was the resistance of the Wye windings?
2. What was the resistance of the Delta windings?
3. Was there a difference in the resistance between the wye and delta windings? Why?
4. What is the purpose of wiring a 3 phase motor to a wye and delta windings?
5. What is the purpose of the auxiliary switch?

Click on the file below to download the Lab Assignment
- HET 119 Wk 13 Lab.docx (100.65 KB)