Originally Posted by
joeavaerage
Hi,
running an asynchronous spindle at only half speed is if not an outright mistake certainly poor practice.
If you run the spindle at half speed, the torque is about the same, but the speed if half, so you only get half the power, so instead of 3.2kW you'd get 1.6kW at best, and even that is likely
to overheat your spindle. In short you have paid a lot of money to get extra power but by not getting a matching VFD half of it is thrown away. Worse I think you'd destroy your spindle
in short order.
I would read it the same way, namely at rated speed ie 800Hz input 8.8A at 220VAC. Were you to run the spindle at 400Hz, the spindle would still take 8.8A but the voltage would be half, about 110VAC
If you tried to apply 220VAC at 400Hz to sort of 'get back all that power' the current would increase to 16A, and it would last for a few second before a puff of smoke stops everything.
The WJ200-022SF is good for 2.2kW. At only 400Hz you could only run your spindle to half speed, ie half power ie 1.6kW. So your VFD would get half power at best without undue risk to the spindle.
If anything goes wrong you have given JianKen the perfect opportunity to wash their hands of it, and to be honest I don't blame them . You are inviting trouble and disappointment. Get the matching VFD,
and I would not trust a cheap one.I personally like Delta VFDs but Hitachi also have a pretty good name.
Craig