In the region up to base speed, it is important to have a high constant torque available.
This is attained with the motor’s electrical winding connected in a wye configuration. This
connection is best for large-diameter, rough-cutting operations, which typically require high
torque at low speeds.
For applications that require higher maximum speeds, some spindle motors have a wye- delta winding selection option. This extends the spindle motor’s constant-horsepower maximum
speed without mechanical gear changes. By simply connecting the motor’s electrical winding in a
delta configuration, the base speed is extended by √3 (√3 x 1,500 = 2,600 rpm), Figure 3.