Bauker Kango keeps tripping out

borrowed a Bauker breaker (240v) to attack some mortar left behind after lifting an old patio. Worked for fifteen minutes (was breaking it with ease) then cut out. It had taken a main trip out in my consumer unit. Reset it, took it out again. The kango wasn’t hot, not even warm so it’s not an overheated motor. Any suggestions please guys?

It was plugged in the kitchen power circuit, via a 10m extension lead (standard reel type). It’s borrowed from a friend so don’t want to return it knackered

It was below minimum on the oil sight glass, so have topped it up but not tested it again yet (working til 10pm every evening since). Would low oil cause it to trip? I’m guessing not

Worn brushes could cause it to stop. So could a broken wire

If the brushes have worn right down, or almost right down, they have the chance of 'dragging' the wire spring around the commutator causing shorts across the armature.
This will trip the circuit, hopefully before it does too much damage to the unit. If you do change the brushes try to access an airline, or can of compressed air, because the brush boxes and commutator area will be full of carbon dust. Carbon dust is a great electrical conductor when you don't want it to be.

Thanks guys
Panic over. Topped it up with oil, fully unwound the extension lead and used the cooker socket and no more tripping.

I’ve got loads to learn on this patio project...