Thread: Carbatec BB-48 Belt Sander, Motor Short Circuit

If you are taking down the house power, I assume that there is a safety switch installed at the meter box and this is what is activating.

This indicates that there is leakage current flowing from the unit, rather than a short circuited motor. A short circuit in the motor would draw extreme current and trip the circuit breaker supplying the unit. The safety switch monitors the current flowing through it on both the Active (supply) and Neutral (return) parts of the circuit, and disconnects if these currents are mismatched by a small amount (30/1000th of an amp or more).

If the motor has ingested hot metal dust, it could have burnt through the insulation in the windings or cables, or could have deposited on the board carrying the starter switch assembly. A simple blow out would not clear metal dust completely, but may move it to another location. The problem could equally be located in the switchgear or interconnecting cable.

From your basic description of the problem, I suspect that you might not have the electrical savvy or equipment to safely dismantle, clean, test and reassemble the unit personally, so I strongly suggest that you have someone with an electrical background triage the problem and try to isolate it, so that you can refer the faulty component to appropriate repairers. For example there is no point in sending the motor to a rewinding shop if the problem is in the switchgear, and no point in replacing switchgear if the problem is in in the interconnecting cables.

Sorry I can't be more directly helpfull.

Mmmm, i dont really have the electrical know how to fix it myself and i dont really want to muck around with it because i could do more damage than good if its such a hard fix, if it involves taking it apart and cleaning and putting it back together id prefer to have a professional have a look, so i guess ill have to find someone who can do some testing perhaps, and your assumption is right, its turning the clipsal switch to the house power within the meter box on the side of the house, because im currently just using a power point within the garage to supply power to my tools etc.

Would it be best to find a general electric motor repairer to have a look?, if anyone knows a place in north sydney for small electric motor repairs thatd be great.

Also when i was looking at the motor again, it started up 4 of the 5 times perfectly fine but as soon as i switched it on the 5th time it would just cause the house powers safety switch to flip off instantly. (i could see a blue arc/spark through the back vent) and im assuming this is what caused the problem because the 4 times previously it didnt have a blue spark, so im assuming its involves something to do with the starting of the motor perhaps, because when i took off the vent cover to have a look to blow air through, it was pretty much pristine clean inside and it hasnt had much use prior to me buying it.