What should the common to run value be when diagnosing the motor windings of a hermetic compressor?

The common to run value for diagnosing the motor windings of a hermetic compressor typically falls around 3 ohms. This value is significant because it indicates the health of the compressor motor windings. When measuring resistance across the motor windings, a reading that is too low or too high can signal issues such as short circuits, open circuits, or winding degradation.

A measurement around 3 ohms suggests that the motor is in good condition and that the windings are intact and functioning normally. If the reading deviates significantly from this value—either being much lower or much higher—it could suggest that maintenance is needed, as it may point to problems with the motor that could affect the overall performance of the air conditioning system.

Furthermore, understanding this value aids technicians in making informed decisions regarding repairs or replacements, ensuring the compressor operates efficiently and reliably.