Course: HET 111 HVACR Electricity I - Spring 2015

Lab Assignments

Labs
Unit 4 Labs

OBJECTIVE: Upon completion of this exercise, you will have a better understanding of the use of an ohmmeter in the HVAC field.

INTRODUCTION: You should carefully review lecture notes and PowerPoint for week four Ohm’s law. This will give you a good background for most of the procedures in this exercise. Email your instructor about anything of which you are unsure.

READING REFERENCE: Ohm’s Law

TOOLS AND MATERIALS: You will need a box of parts from an A/C unit, a pair of safety glasses, an ohmmeter, your notes, and this lab sheet to complete the exercise.

SAFETY PRECAUTIONS: Always ware safety glasses when working in the lab or out in the field

PROCEDURES:

- Get a box of A/A parts from your instructor
- Set your meter to ohms (Ω)
- After you turn on the meter and set it to ohms call your instructor over and have him observe your work
- Attach one of the leads from the ohmmeter to one side of one of the parts from the box
- Be sure to get a good connection
- Attach the other lead from the ohmmeter to the other side of that same part
- Again ensure that you have a good connection
- Read and record the value on the meter
- Have your instructor inspect your work
- Repeat the lab the other parts in the box

Clean up your work area and return the box of parts to their proper location

SUMMARY STATEMENTS: Define the following in your own words:

- Ohmmeter:

- Continuity:

QUESTIONS:

- Why do we use an ohmmeter to check contacts in the field?
- Why do we use an ohmmeter to check continuity in an electric circuit?
- What reading should get on a set of normally closed contacts?
- What reading should get on a set of normally open contacts?

Click here to download the Lab Assignments
- Ohmmeter Lab.docx (22.56 KB)