Application Guide

63-706213

Star Delta

Star Delta is a method to reduce applied voltage to the stator winding starting large motors (see Fig. 10). This reduces starting

current. This also reduces locked rotor torque. Both power and current in Star are less.

415v

240v

Applied

240v

Fig. 10. 415V phase windings in Star.

Delta

415v

Fig. 11. 415V phase windings in Delta.

Full nameplate Power available in Delta (see Fig. 11).

Delta Star

A method to produce a Dual Voltage motor. See Fig. 12.

240v

Fig. 12. 240V three-phase windings in Connect Delta.

Full nameplate Power available in Connect Delta.

415v

240v

Fig. 13. 240V three-phase windings in Connect Star.

Full nameplate Power available in Connect Star (see Fig. 13).

Horsepower is the same in both cases, but current change in a ratio of 1.732 (square root of three). Delta is 1.732 times

greater than Star.