Thread: VFD (?) tripping RCD
The water is flowing.
Apparently changing PD200 from 0 to 65535 (2^16-1) and PD209 to 50 can help. It didn't, breaker still tripped.
Tried extension lead from house socket to workshop as the house wiring is old so it's just got wire fuses and predictably that fuse didn't blow. The VFD still stopped after 15 mins, the motor and displayed an error. I think last time I remembered the error wrong as having seen the error code definitions it makes even less sense than the correct code!
If I look in PD177-180 for the previous faults it's EOCn, ELUNn, EOUd and EOCn in that order. The last error I saw, via house ring main, was EOCn so I've had that one at least twice now. The definition for that error is:
Over current at constant speed. They suggest in the manual:
1) Check whether the motor has got short circuit and whether the insulation of the output wires is good.
2) Check whether the motor is blocked and whether there is a sudden change of mechanical load.
3) Check whether the inverter's capacity is too small and increase its capacity.
4) Check whether there is a sudden change in the power supply voltage.
2 and 3 don't apply, 3 for obvious reasons and 2 since it's stalling whilst the cut is constant and I'm nowhere near the power limit - only about 1.1A.
So that implies it's either an insulation fault with the spindle, or the supply. Unlikely to be the supply since I've tried it from two points. So that leaves the spindle, oh no! For what it's worth I measured each phase resistance and the insulation resistance from each phase to the spindle body at the VFD end (to include the wire) directly after it faulted. Phase resistances are balanced and the rest out of range for the meter.
Suspicion that it's the spindle is backed up by the VFD working just fine on the lathe.
New VFD is on the way, ordered Monday. Think I'll dismantle my VFD now to see if there's anything obvious, like vented caps...
Last edited by Jonathan; 02-12-2011 at 10:30 PM.
Took the case off the VFD, couldn't see anything wrong so I wiggled the wires a bit and now it works!
Ran fine for over an hour cutting Luke11cnc's parts...