Rotary gap nearly done...

To: Tesla List <tesla-at-poodle.pupman-dot-com>
Subject: Rotary gap nearly done...
From: Chip Atkinson <chip-at-poodle.pupman-dot-com>
Date: Sat, 19 Oct 1996 21:21:12 -0600 (MDT)
Greetings,

First, we now have over 250 subscribers!  What have I gotten myself into? :-)

Anyway, I got the rotary gap virtually done today.  I was going to use a 
totally wimpy vacuum cleaner beater bar electric motor to turn it, but 
there was far too much friction in the new ball bearings (!) for that 
motor to overcome.  The vacuum motor's smoke tried to make a break for it, 
but I only let a little escape.
I then went to our local HVAC (sorry, that's Heating, 
Ventilation..., not High Voltage) shop and got an old furnace and 
salvaged the motor.  It's turning out fall is the time to scrounge 
furnace motors and blowers -- good for ventilating ozone. 

I reversed the pulleys from the blower and motor, so the RPM of the 
rotary gap is about 3450 (~2*1750).  Unfortunately, this arrangement is 
hard on the motor as it takes several seconds for the whole thing to come 
up to speed.  During that time, the starting windings are energized and 
the motor gets pretty warm.  The other problem is that the motor, being 
induction, is pretty much a fixed speed.

Since I have 12 studs on the rotor, I get about 690 breaks per second 
with this arrangement.  The rotor is about 12" in diameter, so the dwell 
time is "short".  The question that I have is "Is the 690 bps too high 
for starting out?"  I ordered one of those Carter motors from C&H Sales, 
but I'm wondering if It would be OK to start using the gap as is, or will 
I likely blow a cap?

I took a fair amount of time and care in building the thing, and it looks 
pretty nice.  The other thing that's kind of amazing is how smoothly it 
runs.  I made sure everything was true on the lathe, and used uniform 
parts.  Still, I expected some sort of vibration, but get little if any.
I'm totally psyched about the whole thing.  I also took some pictures, 
and will try to get them scanned and posted sometime in the coming week.

Chip
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 Chip Atkinson 
 http://bhs.broo.k12.wv.us/homepage/chip/info.htm
 --- Everyone is someone else's weirdo. ---
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