Earth leakage problem with Karcher pressure washer

[Timbo1066]

Hi everyone,
New to the forum as i'm looking for a bit of help if it's out there. I'm sure this isn't the right place to post and please please let me know where I should post it for the best exposure! my issue is different, Once the start switch is made the 13A fuse in the plug top blows almost straight away. It's not instant but very quick. Being apprentice trained I like to strip things down so that's whats happened!. Testing has shown me the capacitor is fine at 40 mic, I can't see any switch assembly to switch out a cap and am assuming its just there to phase shift part of the winding - yes? I know winding resistances are fairly low but I feel these are very low at around 5 and 2 ohms. There are 4 wire coming out of the motor (Red, Blue, Black and Grey) and they appear to have slightly different csa's. I've insulation tested at 250V and I have no insulation breakdown to earth but all the winding's seem inter - connected but not dead short. I don't suppose anyone would have a detailed schematic of the motor windings with resistances would they?

I've got it in my head it's an electrical winding issue but it seems so rare I'm after a bit of support really.

Anyway thanks in advance if there are any takers.

Timbo

 

[Lucien Nunes]

Those winding resistances are not unrealistic. The running current is not determined not by V/R but by the impedance which depends on a lot of factors but is much higher than the DC resistance. In a capacitor-start or capacitor-run motor the two windings are connected together at one end. If the auxiliary winding is for starting only, there will be a centrifugal switch to disconnect it.

There is more to testing a motor capacitor than measuring its capacitance. Many capacitors that are failing still have the correct capacitance, but also an unacceptable amount of parallel leakage resistance which might only show up at operating voltage. So the main test of a cap is an IR test.

Start a new thread about this, post some pics of the terminal box etc and we can guide you through tracing the fault.