Re: "vacuum" gaps

Hi Malcolm,

> Scott,
>        You got me thinking about vacuum cleaner motors with this...
> > A motor from a Tri-Star or Rainbow sweeper work well.  A standard
> > canister vacu um cleaner motor will well also, it just pulls a
> > little less air.  Shop-vac moto rs can be used, but they turn at
> > twice the RPM's and scream quite loudly.  They pull about the same
> > amount of air as a standard canister vacuum cleaner. I get mine
> > from a local Rainbow dealer who takes "trade-ins".  I select a
> > vacuum cleaner from the pile that still works and gut it when I
> > get home.  The motors tend to be in poor shape, but if I get a
> > couple of months from it, I've done well and it cost me nothing but
> > a little time.  One nice thing about these canister vacuum cle aner
> > motors is that most of them use a standard bolt circle and pilot
> > diameter for mounting.
> Sorry to change the subject slightly, but I get the impression these
> things rev fairly high. What do you think their suitablility is for
> driving a 10" spark gap rotor?

I'm sure they are high RPM.  I have heard lately of someone wanting to 
do exactly as you describe.  The "Shop-Vac" motors are even higher.  If 
I had to guess, I would say the standard unit turns between 3000-4000 
RPM, and the Shop-Vac type over 6000 RPM.  They do have decent power.

>     BTW, thanks for organizing the capacitor deal. Mine arrived in
> perfect order and well padded.

My pleasure.