Table of Contents
What is the process in troubleshooting an electric motor?
Electrical Troubleshooting in Seven Steps
- Gather information.
- Understand the malfunction.
- Identify which parameters need to be evaluated.
- Identify the source of the problem.
- Correct/repair the component.
- Verify the repair.
- Perform root cause analysis.
What precautions should be taken when checking hermetic compressor motor?
Hermetic compressor motors can easily be diagnosed with a good ohmmeter as open, shorted, or grounded. Spot burnouts are harder to diagnose, but you can still identify them easily by using the resistance readings of the motor. CAUTION: All electric motors should be properly grounded.
Why do you have to be careful with hermetic compressor motors?
Hermetic motors running within their design limits can outlast all the other components in the system. It would be a waste of time and effort to clean a system that wasn’t contaminated, and it would be unwise not to do a thorough cleaning job on a system that was fouled up with the residue from burned insulation.
What is a hermetic compressor motor?
Hermetic compressor: A hermetic or sealed compressor is one in which both compressor and motor are confined in a single outer welded steel shell. The motor and compressor are directly coupled on the same shaft, with the motor inside the refrigeration circuit.
How do you check if a motor is working?
With a multimeter set to low ohms (usually 200), test between each winding terminal and the metal casing of the motor. If there is any reading on any of these then the motor is bad, do not use it. You may find that when it runs ungrounded that the casing becomes live at up to supply voltage.
What are the basic checks you need to do before troubleshooting a motor?
For the supply, test first with the motor disconnect open and locked out. Use your megohmmeter to test the insulation resistance to ground….Final tests and procedures.
- Listen for unusual noises.
- Smell for smoke or hot insulation.
- Feel the motor for excessive heat or vibration.
- Look for possible obstructions.
What are the three types of single-phase motors most used in the industry?
Types: There are a few different types of single-phase motors; some of these are two-valve capacitor, capacitor-start, split-phase, permanent-split capacitor, wound rotor and shaded-pole motors. Each type of motor has its own unique advantages and disadvantages.
How are electrical components checked on a hermetic compressor?
Before testing a run or start capacitor with an ohmmeter, the capacitor should be discharged with a 20,000-ohm 5-watt resistor. The electrical components for a fully welded hermetic compressor are checked at the disconnect box for the compressor unit.
How do I know if my compressor motor is bad?
Some of the signs of a bad A/C compressor are as follows.
- A Lack of Hot Air Being Released Outside.
- Loud or Strange Noises From the Unit.
- Failure of the Compressor to Turn On.
- Circuit Breaker Tripping.
- Leaks Around the Air Conditioning Unit.
- Warm Air Instead of Cool Air Being Delivered to the House.
- Reduced Airflow.
What is the difference between open and hermetic compressors?
In an open compressor, the motor and the compressor housing are mounted separately. Because the open compressor lacks a seal around it, there is risk of refrigerant leakage. A hermetic compressor also houses both the motor and the compressor housing inside a shell.
Which are disadvantages of hermetic compressors?
Disadvantages. They are not intended to repairing since the moving parts are inaccessible if there is any problem you need to do you replace the whole unit. Burnout winding can contaminate entire system. Only electric power sources can run this unit.
How to troubleshoot and diagnose a mechanical compressor?
Attach the pressure module to a DMM and put the module function switch to cm/inches Hg. Connect the module at the suction line service port. Close the compressor off from the low side of the system by front seating the suction service valve. Run the compressor for two minutes. Turn off the compressor and observe the reading.
What are the different types of hermetic compressors?
The capacitor-start induction-run (CSIR) motor is similar to the RSIR. However, a start capacitor is included in series with the start winding to produce a higher starting torque. This motor is commonly used on commercial refrigeration systems with a rating through 3/4 hp (see Fig. 9-37).
What should I do if my HVAC compressor fails?
A catastrophic motor failure within a (semi-) hermetic compressor that contains oil and refrigerant at best involves extensive clean up procedure, and at worst may require equipment, rather than component, replacement, as well as lost production time and revenues.
How to test insulation resistance in compressor motors?
How to test insulation resistance in compressor motors. Never perform insulation resistance testing or operate a compressor when the system is under a vacuum. Remove all wiring from compressor terminals to isolate compressor. Remove compressor terminal bars if so equipped. Clean terminals with a clean, dry shop towel.