What is a 3-lead AC motor?

• A. A dual-voltage motor that can be reconfigured between wye and delta.
• B. A motor with four leads per phase.
• C. A motor that uses remote starting.
• D. A single-voltage motor with internal connections already made; three leads brought out; cannot be reconfigured.

Answer: (D)

The idea being tested is how winding connections and lead counts reveal how a motor is designed to be powered. A three-lead AC motor is a single-voltage design where the windings are already connected inside for that voltage, and only three leads are brought out to the outside. This means you connect it to power and to the starting circuit as designed, and you cannot reconfigure the windings to different voltages or configurations (such as changing between voltages or winding schemes like wye or delta).

In practice, those three leads typically correspond to the common point, the run winding end, and the start winding end (the start winding often needing a capacitor). Because the windings are fixed internally, there’s no option to reconfigure for another voltage or connection scheme.

The other choices don’t fit because they describe motors with multiple leads used for different configurations or purposes: a dual-voltage, reconfigurable motor implies more than three leads; a winding arrangement with four leads per phase isn’t characteristic of a standard 3-lead single-voltage motor; and remote starting refers to how you start the motor rather than how the windings are brought out.