Hi All
I have an Okuma LC20 being run off a rotary phase converter (8kw) with a large 30 hp idler motor in parallel. Being in country Australia the supply is 230v single phase with no 3 phase available. I have added the 30 hp idler as it supplies the extra grunt to accelerate the DC spindle without any loss of phase errors occurring. My problem is that I have overvoltage error anytime I stop/slow the spindle from a speed greater than 100 rpm. I am sure this is happening because the SDU600-w driver tries to feed the excess dc bus voltage back upstream into the phase converter. Normally a utility 3 phase supply grid would happily accept this charge but not in my situation.

Is there anyone with knowledge of the machine/ SDU600-w driver who has modded to allow a slower decel rate ? I am aware that I could g code the problem away by creating a macro involving dwell to step reduce the ramp rate but I would prefer to do something off the driver board. Maybe bring in to play a switch/ resistors to dump the excess voltage as regenerative braking won’t suffice. Thanks Phil