Deckel FP-NC Spindle Speeds

I am curious as to how the spindle speeds on an FP-NC are actually controlled. Looking at the wiring diagram it would appear the spindle motor is a simple pole changing three phase motor connected directly to the supply via switch gear etc.

I know the speed can be set via the Dialog code addresses S00 – S3150 or manually by the console control, but without a VFD or electro-mechanical gearbox how is this achieved.


thanks Adrian.

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