Sip 10" compound mitre saw not working

[plumAJP]

I grabbed this saw off my father before he binned it in the hope I could fix it.

The problem with the saw is as soon as I pull the trigger it trips the electric . I've stripped the motor housing off and the brushes are ok, I've cleaned them and blown all dust out of the saw and nooks.

The wire on the trigger looks to be original and untouched but I can't fathom it. I'm not an electrician just good at stripping stuff and putting it back together.

I've wired the motor direct to 12v battery and it spins fine, I've wires the trigger to switched 12v live and it works.

I've wired it to 240v in a simple lay out with switched 240v and it trips the electric. I don't know how to fix it so can you guys help.
This is the original wiring if you can follow it

Switch wiring

• plumAJP
• 21 Apr 2014
• 1

 

[foxhole]

Some crude chop saws trip the electric due to the power surge, B&Q recalled a whole series like that. I have one in the garage, trips anything below a 30 amp breaker.
Maybe the motor brushes have worn out and it's just arcing when trigger pulled. They used to be supplied with spare brushes.

 

[joe-90]

Does it trip the breaker (overcurrent) or the RCD (leakage).

 

[plumAJP]

I will check what amp breaker I have. It's tripping the breaker yes.

There is no rcd, just the breaker in fuse board/consumer unit.

How can I tell if brushes are worn? They are touching the circular thing at the rear of the motor and I have removed them and there's a about 1.5cm of grey body left on each. I did not get any spares as old man binned them most probably.

 

[joe-90]

Do you have portable RCD type plug? If it's tripping the RCD the windings are probably shot. Try it on the 30 amp ring main rather than a 16 amp radial. Ask in the electrical forum.

 

[plumAJP]

I don't have a rcd portable plug.

I will try on the 30amp ring and report back.

What are windings and how would they mess up.

Don't forget it works off the 12v car battery so the motor spins the blade and trigger works.