Tuesday, July 28, 2009

Generator bearings

Troublesome bearingDismantling the generator was pretty straightforward, as was getting the first bearing off.

The second bearing proved a little more troublesome, and as soon as I chipped a piece of cast iron off of the rotor I stopped trying to prise the bearing off with a piece of steel bar.

I did know better before I even started, but thought I'd just give it a try...

Anyway, after hauling it round to a few likely places to get the bearing removed using a proper puller, I gave that up as a waste of time. At one garage, the mechanic could not even comprehend what I was trying to do!

Back on board, I knocked up a very crude, but effective, puller with a few bzzts of the old welding machine.

If I ever need it, version 2 will have sliding jaws and a nut/bolt arrangement to ease a bearing off. This that you see was the quickest and easiest to craft up for the job in hand.

A few knocks with a hammer and the bearing popped off in no time.

I should have done that in the beginning.

By way of an update - I did take a picture of the plate on the side of the generator, but it did not come out at all well. I'll try again when I'm next on board.

8 comments:

  1. Anonymous12:40 AM

    Nice bearing pulled Tim! I think the fan part that's chipped is cast aluminium, not iron. You could file off an equivalent bite opposite to restore the balance, or leave it.

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  2. Anonymous12:45 AM

    Hi Tim, Ingenious puller! This comment probably belongs with the previous Generator post, but .... I think you might have a brushless alternator. In such a device the magnetic field for the rotor is produced by a stationary coil which somehow surrounds the rotor. Looking at the previous picture of your generator, we see a donut shaped structure in between two sections of stator windings. Are there 2 wires attached to that donut? And I guess there must be some large diodes hiding somewhere. And a regulator, as well. If all of the above are there then that's what you have.
    PS If you clean it well you can probably epoxy the fan bit back on. I guess the generator doesn't spin that fast.
    Regards,
    David

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  3. Fred (WWR)3:45 AM

    Necessity is the mother of invention, so they say :)

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  4. Well done Tim, great Job! probably be as well to balance it up again in some way just in case it vibrates badly, enough noises on a boat without that I guess.

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  5. Hi Anonymous

    Thanks. It's such a tiny piece it's not going to make any significant difference at the speeds the main engine turns it at, so I'll just leave it.

    Regards

    Tim

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  6. Hi David

    Thanks - yes it must be a brushless alternator.

    I'm still kicking myself for not getting a proper picture of the name plate.

    Regards

    Tim

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  7. Hi Fred

    Yup - the puller looked so crude, I amost didn't post it.

    I thought it may give someone else an idea of what (not) to do, some time in the future, if they have a similar issue.

    Cheers

    Tim

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  8. Hi Rob

    I'm not expecting balance to be an issue here, as the piece broken out is so small.

    Regards

    Tim

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