What reading would indicate a good clean system when testing compressor motor windings with a megger?

A reading of infinity when testing compressor motor windings with a megger indicates that there is no electrical connection between the windings and the ground. This is essential for determining that the insulation of the motor windings is intact and that there are no short circuits. A good, clean system will show infinite resistance, signifying that the windings are well-insulated, which helps prevent current leakage that can lead to system inefficiencies or safety hazards.

If the insulation is compromised, typical megger readings would show lower resistance values (like 1, 10, or 1000 ohms), which would indicate problems such as short circuits or degraded insulation. These lower readings suggest that the windings may be conducting electricity in an undesirable manner, thereby impacting the overall functionality of the air conditioning system. Therefore, the indication of infinity is crucial for confirming the health of the compressor’s insulation integrity, distinguishing it as the correct answer.