How is a 12-lead motor connected for low voltage wye (example 230 V)?

• A. Connect power to leads 1, 2, 3; connect 4, 5, 6 together (neutral); connect per phase 7&10, 8&11, 9&12 in parallel.
• B. Connect power to leads 7, 10; 8, 11; 9, 12 and leave 1-3 unconnected.
• C. Connect power to leads 4, 5, 6; neutrals 1-3.
• D. Connect power to leads 1, 2, 3; tie 7-10; 8-11; 9-12 as separate groups.

Answer: (A)

In a 12-lead motor designed for low-voltage wye operation, you arrange the windings so that each phase consists of two windings in parallel, with a common neutral point. That lets the motor run on a lower line voltage while keeping the same current capability in each phase.

So you apply the supply to the ends of one side of each phase (the “line” ends), and you tie the opposite ends of the paralleled windings together to form the neutral. In the numbering given, that means:

• Put the three supply lines on leads 1, 2, and 3.

• Tie leads 4, 5, and 6 together to form the neutral.

• Parallels the two windings in each phase by connecting 7 with 10, 8 with 11, and 9 with 12.

This configuration yields three parallel windings per phase from line to neutral, which is the intended low-voltage wye arrangement (around 230 V in the example). If you omit the parallel ties or connect the windings in the wrong groups, the motor would not be wired for the proper voltage or current rating.