Wide Constant Power Control Using Winding Selection
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7.1 Features of the Winding Selection Wide Constant Power
Drive
The AC main shaft Motor winding selection function is provided as an effective method of increasing the
constant power control range of the machine-tool main shaft drive. The features of the function are shown be-
low.
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Wide Constant Power Control Range
A constant power range of 1:12 can be obtained using the Motor drive without using a gearbox.
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Small Controller Capacity
When expanding the constant power control range using the AC main shaft drive, the Motor current must
also be expanded in the low-speed area, and the controller capacity must also be increased. When using
winding selection, a constant power control of 1:12 can be obtained using a standard controller capacity,
simply by changing the Motor winding connections.
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Good Control Stability
Winding selection enables optimum control by dividing the constant power control range into low-speed
coils and high-speed coils. Consequently, stable control can be obtained by increasing the loop gain as
well.
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Special Magnetic Contactor for Winding Selection
The magnetic contactor is a compact model developed for winding selection. The contactor has a mechani-
cal life of 5 million operations minimum.
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