What should be observed when checking the windings of a three-phase motor?

What should be observed when checking the windings of a three-phase motor?

• A. All three terminals should show different resistance
• B. Only one terminal should show continuity
• C. All three terminals should show the same resistance
• D. One terminal should be grounded

Answer: (C)

When checking the windings of a three-phase motor, all three terminals should show the same resistance. This indicates that each winding is balanced and functioning properly. A uniform resistance among the windings suggests that they are in good condition and that there are no significant differences in the winding resistance that could lead to operational issues or inefficiencies in the motor. If the resistances were different, it could indicate problems such as worn windings, potential short circuits, or failures within one or more windings. In a properly functioning three-phase motor, the equal resistance values also help ensure that the motor will run smoothly and at optimal performance levels, maintaining phase balance during operation. Other options present various situations that would not reflect a healthy three-phase motor winding configuration. For example, observing one terminal with continuity or differing resistances could imply faults or imbalances that may require further investigation or repairs. Similarly, grounding one terminal would suggest a malfunction that needs immediate attention, as it can lead to short-circuit conditions or safety hazards.

When checking the windings of a three-phase motor, all three terminals should show the same resistance. This indicates that each winding is balanced and functioning properly. A uniform resistance among the windings suggests that they are in good condition and that there are no significant differences in the winding resistance that could lead to operational issues or inefficiencies in the motor.

If the resistances were different, it could indicate problems such as worn windings, potential short circuits, or failures within one or more windings. In a properly functioning three-phase motor, the equal resistance values also help ensure that the motor will run smoothly and at optimal performance levels, maintaining phase balance during operation.

Other options present various situations that would not reflect a healthy three-phase motor winding configuration. For example, observing one terminal with continuity or differing resistances could imply faults or imbalances that may require further investigation or repairs. Similarly, grounding one terminal would suggest a malfunction that needs immediate attention, as it can lead to short-circuit conditions or safety hazards.