Hi all,

Mate went to use his garden chipper the other day and it ran for half
an hour then stopped. He checked for blockages and it was clear and
left it for a while and tried again but nothing. Changed the fuse in
the plug and fined it up but after a second it stopped again with what
turned out to be another blown fuse.

I had a look at it with him today and I first tested the run capacitor
that checked out at around it's marked 22uF.

Measuring across the (synchronous) motor stator with a DMM shows about
an ohm. Measuring across the mains plugs on similar power rating
pressure washer and compressor showed around 4-5 ohms (suggesting 1
ohm might not be too far out, once you take into account the
resistance of the mains leads and switches etc)?

Stripping the motor (just for a closer look) found the bearings to be
clean and free and the automatic friction brake to be working ok (by
hand).

Powering the stator on it's own on the bench immediately tripped the
16A MCB in his garage (not sure if that is a valid test)?

We put it back together and again it tripped the MCB straight away
with only a twitch on the motor.

So, outside of a potentially partially short stator winding (not that
there was any sign of damage, corrosion or smell of overheating or
burning), I'm wondering if the run capacitor is failing under load,
even though it tested ok on the bench and if it is breaking down,
could it cause the symptoms we are seeing do you think?

If not, is it just a failed stator winding or what please?

Cheers, T i m