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Re: Rotor BPS
Subject: Re: Rotor BPS
Date: Mon, 26 May 1997 14:55:27 -0500
From: "Robert W. Stephens" <rwstephens-at-headwaters-dot-com>
To: Tesla List <tesla-at-pupman-dot-com>
> Date: Sun, 25 May 1997 22:41:46 -0500
> To: tesla-at-poodle.pupman-dot-com
> Subject: Rotor BPS
> From: Tesla List <tesla-at-pupman-dot-com>
> Subject: Rotor BPS
> Date: Sun, 25 May 1997 18:14:45 -0700 (PDT)
> From: gweaver <gweaver-at-earthlink-dot-net>
> To: Tesla-at-pupman-dot-com
>
>
> Will a non sync rotor work OK on a TC at 5KW to 16KW or do I have to
> have a
> sync rotor?
>
> Someone told me 1200 bps or above works best for a rotor. How many bps
> works best?
>
> I have been thinking about building a rotor with 6 contacts on the non
> rotating disk and 7 contacts on the rotating disk. This will give me 42
> BPS
> per RPM. Using a 1725 RPM motor it turns 28.75 RPM's per second. 28.75
> x
> 42 = 1207 BPS. Is that to many BPS?
>
> Do I really need a rotor? My vacuum fan spark gap is doing fine up to
> 5KW.
> I am a getting very good spark output of 6' up to 8' max. Haven't tried
> increasing the power above 5KW yet.
>
>
> Gary Weaver
>
>
Gary,
IMO you should go to a rotary break for sure once you are working at
5 kVA or more. I would probably go that route at 3 kVA personally.
There's just *something* sweet about rotary systems.
1200 PPS (presentations per second) is way too much. This represents
enormous abuse of a system capacitor. There may be times where such
break rates have merit, but not for the purposes you are attempting
to achieve now.
With a 1725 RPM motor and 14 rotating contacts working between two
stationary contacts you will get a rotary break that will work fine
producing about 400 presentations per second. In my own experience
results from larger coils is fantastic at this speed. If you place
an additional set of two stationary contacts elsewhere around the
periphery of your rotating disk so that they line up perfectly at the
same time as the first set, and put this second set in series with
the first so that you end up with 4 total series gaps, this will
likely be even better. This gives you half the effective physical
dwell of a single pair of contacts, which will be desireable if you
are employing bolt heads as contacts. They tend to give long
presentation times because they are so large in physical diameter.
Such an arrangement should work fine between
5 and 16 kVA input provided you use adequate sized electrodes and
appropriate contact materials. Brass bolts are O.K. but not long
lived. Tungsten, IMO, is best hands down. Stay away from stainless
steel bolts. They release toxic metal vapour as they dissolve.
I like to employ a vacuum cleaner turbine set up as a blower forcing
high speed air through 3/4 inch nozzles directly at the zone of
presentation between the stationary and rotating contacts. I find
this helps with quenching and with it I've never needed to employ
series static quench gaps.
Have fun,
rwstephens