Service Reference Manual | TROUBLESHOOTING |
2.Set an ohm meter to the lowest possible setting. On a note pad, write the following: “C to ground”, “S to ground” and “R to ground.”
3.Using the ohm meter, check for continuity between C terminal on the fusite plug and the case of the compressor (a spot may have to be cleaned on the compressor to get a good reading.) Record what was observed on the note pad next to the heading “C to ground”. Do the same to the other two terminals and record the findings in the proper places.
4.If any sign of continuity between any of the terminals and ground was observed, recheck the terminal to confirm that the readings were correct. Any indication of continuity between any of the terminals and ground would point to an internal winding being shorted to the compressor case. This suggests that the compressor has an internal failure and it would need to be replaced.
5.If no continuity is noted between any of the terminals and ground, the compressor must be checked out further.
Checking Windings
The following test is used to check the condition of the internal start and run windings.
1.Write the following down: “C to S”, “C to R” and “S to R.”
2.Using the volt/ohmmeter, measure the resistance between terminals C and S. Record the findings on the note pad in the correct place. Measure and record the resistance between the remaining terminals in the same manner.
The following examples show how this information can be used to deter- mine if there is an internal failure.
Example #1 |
|
C to S (Common through Start Windings) | 3.5 ohms |
C to R (Common through Run Windings) | 1.5 ohms |
S to R (Start Windings through Common and Run Windings) | 5.0 ohms |
A resistance measurement between C to S shows that there is continuity between the common and start terminals. The reading between terminals C and R proves that there is continuity between the terminals through the windings. The resistance recorded between S and R is actually a reading of the entire circuit within the motor (S through C to R).
A determination of the condition of the motor windings can be made with the information just collected. The following steps show how this is done.
1.Add the readings from “C to S” and “C to R.”
C to S (3.5 ohms) + C to R (1.5 ohms) = 5 ohms
