XJ12-300 (Real Bull 9512) motor problems.

I have an Amadeal XJ12-300 mini mill, bought used.

I took off that spring thing and fitted a gas strut, then fitted three DRO's. It was the bees knees, I thought. But I was truing of a hole using an 8mm end mill as a reamer, I went too deep, the end mill jammed and teeth flew everywhere.

I bit the bullet and ordered a belt drive upgrade kit from Amamdeal, Great service, ordered it on Sunday through EBay and had it fitted on the milling machine on Tuesday morning. Wonderful, for two days

It started kicking and farting with a grating noise from the top end, I thought that I had pulled the belt too tight and knackered the bearing on the motor, so took off the end cap, and the bearing on the pulley end looks and feels perfect. I ran it under power and it still kicks with no load on it and every time it kicks there are blue sparks from the brushes. If I turn it by hand there is a slight squeaking noise from inside it.

Now I know next to nothing about electricery, is the motor caput or is it the circuit board, and where is the best place to get replacements.

Edited By John Durrant on 14/08/2014 16:22:36

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I would say that the brushes have gone south. (quite common on some imported DC motors)

Don't keep trying to run the rascal until they are replaced.

Nick

Hi John,
I do not think this problem will be the circuit board. It could be the brushes as suggested by Nick or it could be the insulation breaking down between sections of the winding. It could also be a build up of carbon from the brushes between segments of the commutator. One other thing to check is that non of the connections between the ends of the windings and the commutator have become partly unsoldered.

Les.

Had a look at the brushes and they look OK to me, about 20mm long, smooth face and with a good spring on them. I can't see anything wrong with the winding or other parts.

The DC motor brushes on my Warco WM16 wear very quickly and give this problem.

Mark P.

When I bought my XJ9525 from Amadeal around 7 years ago I had similar noises from the motor. When I stripped it down the magnet had come unglued from the casing. Hugh replaced it F.O.C. straight away.

Edited By Paul Barrett on 14/08/2014 19:35:19

Although I am not keen on doing it, electricery is a dark art to me, it looks as if I must do a full strip down of the motor. I am afraid the Hugh will not help me though, I asked him for an XJ12-300 and he could not supply it for a month or so, so I bought a used one instead.

You pay your money and take your choice.