Bob,
The small motor was fully enclosed, I could not see the brush on com pad action, but every now and then it would quiver in the oil, then smooth up, I suspect it might have been arc burn like you say, and maybe a chunk of brush breaking off.
That is why I will use a bigger motor in clear oil, the contact point is in clear view.
Ron
--- In electricboats@yahoogroups.com, "Bob Noble" <bnoble@...> wrote:
>
> Hi Ron,
> Just some more thoughts on the running brushes in liquid.
> I know they run them in gasoline. However there might be a problem running
> them in oil.
> When I worked for HP in the Reliability Physics Lab, I learned that a coat
> of oil or grease on electrical things would stop corrosion dead. This is
> mostly because air can't get to the metals to complete the corrosion
> process, which is also a battery cell. Not to confuse the big battery with a
> corrosion cell, which is nothing more than a very small battery. Anyway,
> this worked so good that some techs decided to put a coat of oil on some
> relays contacts, which soon started to fail in droves for our customers. The
> problem turned out to be that when the contacts arced, the arc carbonized
> the oil and this would soon prevent the contacts from closing.
> So, this could be problem for a brushed motor in oil, however, since the
> brushes are running in an oil system thus, no air, maybe no arc over either,
> which, I think is likely the case.
> So, my rule of thumb for things that can benefit from a coat of oil or
> grease is if it doesn't move, it will benefit and if it moves, it could
> cause a problem, such as relay contacts and switches and brushes, if not run
> in a liquid. :O)
> I find that most oils and greases are non-conductive, but I use dielectric
> grease if I want to be sure around electrical stuff. Battery posts, I put a
> few drops of thirty weight on top and on the bolt to let the vibrations
> spread it out. Or I grease them with grease gun grease as it's readily
> available. Keeps the salt water off too.
>
> Bob Noble
> http://www.sonic.net/bnoble
> -----Original Message-----
> From: Ron
> Sent: Friday, August 26, 2011 11:26 AM
> To: electricboats@yahoogroups.com
> Subject: [Electric Boats] Re: re New Ideas ?
>
> As for the oil cooled motor, a circulating and filtered system should allow
> that E-Teck? 30HP output for 30 seconds to be extended to constant duty or
> close, provided the oil flow and temperature are moved at a rate that takes
> away that heat rejection.
> I have seen many motors in liquid, just not brushed units, as Arby
> mentioned. I just feel the increase of power through smaller electrical
> things, along with capture of usable heat, otherwise wasted, should be
> something of interest to almost everyone.
>
No comments:
Post a Comment