....
Ignoramus2176 wrote:
I wish that the VFD reduced braking efforts, if it detects
overvoltage, instead of tripping on overvoltage. This is really not
too smart on the part of the VFD, unless I missed something. If it
could do that, then the mill would stop almost instantly at low RPM,
and longer at higher RPM.
Some do. Instead of a fixed ramp time from 0 - set speed, some also have
a ramp rate, in Hz/sec. That would take less time at the lower speeds.
Most of these drives have SCADS of hidden options that only become obvious
on the 10th reading of the manual.

Jon

Would you happen to know about the specific case of Hitachi VFDs? My CNC
mill would only stop from top speed in 1.4 secs or trip (9 secs. before
brake) . Takes the same 1.4 secs. from low speed.

I found one "back door", there's a second profile allowed (switched based on
an input) so I set max Hz to 30 and decel time to 0.2; I'm still working a
way to to switch for tapping.

karl