I have a nice Simens 370W Micromaster vector VFD which can ouput 0-650HZ (way cool device), and an italian 370W three phase motor rated at 1380rpm @50Hz. They work (ebay specials).
They will be used todrive a Sherline ER-16 spindle:
http://www.wrathall.com/Interests/CN...nkenDeckel.htm
I have set up the head to allow for four step sheaths, but am wondering what the practical frequency/RPM limits are for a standard motor. It was built in 1986, and there is no mention of Invertor duty etc on the motor.
The lower RPM limit is set by motor cooling, and the upper limit by armature winding strength right?
I have set the VFD to a setting which automatically reduces current progressively to 50% set current at 50% RPM. What is a practical upper limit for a standard motor? 100Hz? 200Hz? So far I only tried up to 75Hz to make sure the inverter works.
At this stage I have almost no milling experience, and am working on a small model radial (edwards radial 5). I have followed Swedes learning experience with hi rpm spindles, but was only aiming for a speed range of about 300-3000 so far.
If the VFD/motor would survive 25hz to 100Hz range, then I could probably get away with using the Sherline two step sheath and just make one more for the motor.
What frequency ranges are you using for your invertors?