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Re: spark gaps
Tesla List wrote:
>
> > Subject: Re: spark gaps
>
> >From ccurran-at-execpc-dot-comThu Oct 24 22:43:56 1996
> Date: Thu, 24 Oct 1996 19:07:39 -0500
> From: Chuck Curran <ccurran-at-execpc-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: spark gaps
>
> Tesla List wrote:
> >
> > >From bert.hickman-at-aquila-dot-comWed Oct 23 22:14:09 1996
> > Date: Wed, 23 Oct 1996 09:29:09 -0700
> > From: Bert Hickman <bert.hickman-at-aquila-dot-com>
> > To: tesla-at-pupman-dot-com
> > Subject: Re: spark gaps
> >
> > Tesla List wrote:
> > >
> > > >From rwstephens-at-ptbo.igs-dot-netTue Oct 22 21:44:46 1996
> > > Date: Tue, 22 Oct 1996 22:04:58 -0500
> > > From: "Robert W. Stephens" <rwstephens-at-ptbo.igs-dot-net>
> > <SNIP>
> > >
> > > All,
> > >
> > > I've been meaning to share my thoughts on the use of a vacuum cleaner
> > > blower to negatively pressurize a fixed gap spark gap container and
> > > draw outside air through the gaps and then after electro-treating the
> > > nitrogen in the air into nitric acid and the oxygen onto ozone, this
> > > nasty stuff gets sucked through the windings of the blower motor,
> > > since vacuum cleaner blower motors are designed that the air sucked by them
> > > passes over and through the motor windings for cooling. Has anyone ever
> > > heard of the concept that ozone attacks electric motor insulation and shortens
> > > motor life? Somehow this design concept appears flawed to me.
> > >
> > > rwstephens
> >
> > Robert,
> >
> > American Science and Surplus has a high speed 120 V vacuum
> > motor/assembly ($12.00) that sucks clean air through the motor! I just
> > replaced my previously zapped motor, and discovered that the little fan
> > on the motor shaft at the top draws clean air through the motor and into
> > the vacuum chamber. This probably reduces the total vacuum you can draw,
> > but otherwise it seems to run OK! Maybe it was a manufacturing screw-up,
> > and this is why they're surplus!
> >
> > -- Bert --
>
> Bert:
> I also purchased a vacuum motor from American Science and Surplus and
> think it is a good deal. As a point of information the motor I received
> has a die cast aluminum endbell that only the motor shaft passes
> through. There is no other openings on this particular motor, which is
> called a "HCX-SINGLEPHASE SERIAL MOTOR" Made in China, on the label. The
> sheet metal fan housing only has the single suction opening on the
> bottom, with no visible means of the stator cooling air to pass into the
> actual suction chamber. I'm sort of cheating here. Since I've worked
> in motor manufacturing for 20 years, I've seen a few of these before
> -- we machine about 11,000 endbells per day at this point. I was going
> to disassemble this one to see if there might be a shaft seal too, but
> it works so nice, why risk messing it up! Yours might be similar to this
> one, take a peek down by the end turns of the stator winding that's
> closest to the big fan housing and if your's is the similar, you'll see
> it is a solid casting--tough to see! Enough suction to pull the walls
> down.
>
> Chuck
Chuck,
I had a chance to look more closely at mine - it's the exact same one
you have, with the large end casting. In looking at it a little closer,
you're absolutely right! The cooling air that's sucked through the motor
_doensn't_ get mixed with the vacuum air flow after all. I was wondering
why this little devil could draw such a strong vacuum if it was letting
air in through the motor. Now I know - it doesn't! I like this little
unit even better now! :^)
Thanks, Chuck!
-- Bert --