Just found this old british motor - bit of help bringing it back from the dead?

[strang]

This old motor has come into my possession and want to bring it back to life for my wife's jewellery hobby.
Gave it a clean and sorted the plug.
Has 5 speeds (?!) and at the moment speeds 1, 3, 4 are all good and work well. However when speeds 2 or 4 are switched to, it trips a fuse in the house switchboard.
Any idea why this would be? Any solutions? Be nice to bring it back to it's former glory as it's 1.5 hp and seems like it hasn't been used very much.
Any help much appreciated.

 

[winchman]

If that's a grind stone take it off until you know its correct speed rating and its not cracked.

 

[dobbslc]

Could be tracking down to earth on those old wires where they touch the casing if it's an RCD that's tripping, if it's an mcb then the windings could be shot.
I would change the cables ( internal and the flex ) and clean all the dust off of it then try again.

 

[MattH]

Leave on one of the working speeds. Job done!

Look at new polishers and they don't have variable speeds.

 

[DanielW]

I think to get to the bottom of it you'd need to draw a diagram of the switching arrangement.......maybe those two positions are a reverse? and are wired differently?