What is the most common configuration for three-phase motors?

• A. Delta
• B. Wye
• C. Series
• D. Parallel

Answer: (B)

In three-phase motors, the windings can be connected either in delta or in wye. A wye connection ties one end of each winding to a common neutral point, so each winding sees the line-to-neutral voltage, while the line-to-line voltage is the square root of three times that phase voltage. This setup is advantageous because it often lines up with higher-voltage power systems and lets you take advantage of the neutral for control circuits or low-voltage sensing. It also means the windings can be rated for a lower phase voltage, which simplifies insulation requirements on many motors designed for dual-voltage operation (delta for a lower line voltage and wye for a higher line voltage). Because of these practical benefits in typical industrial power distributions and motor designs, the wye configuration is the most commonly used.