Re: Disk size for 3600 RPM sync TTY motor

to: Gary

We have used a 1/4 inch thick type LE phenolic disk with two 1/8 inch TIG
electrodes x 1 inch long.  This works fine.  I would guess a 3/8 inch rotor
would contain too much mass for the small 1/8th HP motor to operate
properly.    This works good on coils up to 4 kVA, after that you need to
convert 1 HP normal motors to synchro mode to get approx 1/4 HP to handle
1/2 inch dia brass feedthrus holding tungsten screw in tips.



-----Original Message-----
From: Tesla List <tesla-at-pupman-dot-com>
To: tesla-at-pupman-dot-com <tesla-at-pupman-dot-com>
Date: Wednesday, June 09, 1999 7:40 PM
Subject: Re: Disk size for 3600 RPM sync TTY motor

>Original Poster: FutureT-at-aol-dot-com
>In a message dated 99-06-08 16:49:33 EDT, you write:
>> I was wondering what size disks others have been using with 3600 RPM TTY
>>sync motors?  Is the problem one of rotating mass, where it just can't
>> get over the startup hump, or is it air drag, where any attempt at such
>> prominent rotating electrodes would be too much drag for this motor?
>> Regards, Gary Lau
>> Waltham, MA USA
>  >>
>My guess is it's air drag that's the problem.  The sync motor I used
>at 3600 rpm is a 1/12HP teletype unit, and I used a 3/8" thick 8" dia.
>lexan rotor with 2 or 4 spinning electrodes.  The electrodes are 3/8"
>threaded rod with nuts on either side of the rotor to hold them tight.
>The motor locks up synchronously at about 75 - 80 volts, so there's
>some good leeway during normal 120 volt operation.  I also have a
>similar, but smaller 1/20th HP motor, but I never tried it with a rotor.
>But my guess is the 1/20HP would not be quite enough for my rotor,
>nor yours.  Did you try using 140 volts from a step up variac to see if
>that helps?  Is yours the 1/20HP type?  I have some doubts that my
>1/12HP motor would handle the pipe type electrodes.  It is possible
>that a 1/4 or 1/2HP motor would be needed.
>John Freau