Monday, 25 November 2013
variable speed headstock
Finally got around to converting my headstock to variable speed DC control. The Taig lathe comes equipped with a set of 6-step pulleys intended to be run from a ~1550 RPM AC motor. This gave speeds of 525, 825, 1300, 2100, 3350 and 5300 RPM.
The new variable speed drive will allow 0-5000 RPM operation, with simple current limiting and load compensation adjustments. Under load (when cutting), the controller will increase power to the motor in an attempt to keep the revs constant.
The drive is from KB Electronics (model KBIC-120) with the auxiliary heatsink and barrier/fuse accessory kits; good for 1HP and 12A. The motor is only 5.8A and .40HP so there's lots of margin in the system. At some point I may upgrade to a shunt wound motor from the brushed permanent magnet unit.
The control was purchased from Canadian Drives Inc. who gave great advice.