Hi,
I am finishing a self designed CNC mill. It has a chinese spindle and 2.2kW Huanyang VFD bought as a pair.
Basic testing has been going well and I wanted to make an aluminium piece to hold a ballnut. Surfacing the block went well and provided a very satisfactory finish. I went to cut the 28mm central hole with a 8mm 4 flute end mill. The first cut was 1mm and then 2mm each time down to 30mm.
The 1mm cut went well but as it got into the second but where it was biting a bit more material there was a pop and flash from the connector going into the spindle. Presumably a short to ground since this tripped the differential and the 6A trip switch. ( 6A may have been a bit light, I had a 16A in there too and seem to have connected then to the wrong cct ).
I slowly powered things back up intending to withdraw the tool with manual commands the the GCODE interpreter. When I reset the trip feeding the VFD, there was a crackle and healthy coil of smoke !
Examination of the spindle connector shows blackening due to the arc but no obvious short. For the moment I am guessing that something is a bit too close when assembled and as I was pulling more load with the heavier cut, the VFD voltage rose higher than before causing an arc. The arc may have triggered a high voltage back EMF which took out some components in the VFD. When I powered it back up ( supposedly in a stopped state ) it went into a fault condition which burned out some key components.
It is probably not worth stripping the VFD to envisage repair, it was fairly crackling in the second before I cut the trip switch, but I would like to know as much as possible about what occurred to avoid a repeat performance when I get a new controller.
The circuits look well made but that does not mean they are not cutting corners with protection circuits to cut costs. If my guesses at the sequence of events are correct I would have expected the drive to be protected against spikes coming back from the motor and obvious fault conditions like a short circuit on the output.
Does anyone have any experience of these Huanyang VFD controllers going wrong?
Thanks for any info.