This link shows a photo of the inside of the rear cap of the dis-assembled motor
http://tinypic.com/r/dcvqk7/9 <
http://tinypic.com/r/dcvqk7/9>
You will see there are housings for four trapezoidal shaped carbon brushes, which are fitted as two pairs. Each brush has a spring behind it which keeps them in contact with the rotor as they wear (the issue I had was that my brushes were jamming in the plastic housing - whether they has somehow increased in size* since new I don't know, but I just rubbed the edges on some 120grit paper until they would slide easily in the housing again.
As you can see the brushes are paired, and where the two wires from the brushes join, that is the rear (or rather the ‘inside’) of the terminal that projects from the back of the motor housing to which the cables attach.
If you do take it apart be careful as one of those terminals (the positive one) has an insulating washer that passes right through the cap itself so prevent any contact between it and the metal of the motor which is of course ‘ground’ or negative.
Putting it back together was a nightmare at first because you cant easily hold four brushes in position while you locate the rotor shaft into it’s bearing in the end cap. In the end I found it easier to withdraw the rotor, position the end cap correctly on the rotor and then mate the rotor/end-cap assembly with the rest of the motor case.
On the boat I was unable to remove the motor on its own without removing the entire windlass. I’m not saying it isn't possible with some fancy tool or other, but I didn't have room to access the two bolts that attach the motor to the windlass.
The current manual on the Maxwell site for the VC500 and VW500 is not the same as my windlass which is - I think - simply called a Maxwell 500. The more recent models seem to have a more complex gearbox, whereas the original 500 is a simple worm drive gear arrangement. I don't know if the shaft diameters are different.
I hope to do the disassembly and oil seal replacement in the next week or two and will take plenty of photos as I do so. I will then write an article for the website.
It did occur to me to replace the bearings at the same time, but when I thought about it I realised that the motor doesn't turn very fast and it’s total operating revolutions in over 20 years is probably less than (for example) an electric drill or (34000 rpm) router does in in a week! The bearings really should be OK, but I will look when I disassemble it and they are cheap enough to buy if they do need replacing.
By the way, maxwell being a NZ company, all parts are metric!
Hope this helps
Graeme
*I did have gear oil leaking (which is why I’m replacing oil seals), and wondered f that has contacted the brushes and caused them to swell
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