Re: dc rotary motor

["Paul Mathus" <pmathus-at-learningco-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

     Yes, I've seen people use dc motors with a variable speed control on 
     async rotary gaps.  The guy I know personally who does it pretty much 
     just runs it full speed, and i wonder if it's really worth the expense 
     to buy a dc powersupply/speed control.
     
     360 watts should be a pretty beefy motor.  If you're worried about 
     interference, i'm guessing that a braided cable sleeve tied to ground 
     would take care of it, but i doubt you'll have a problem. Could be 
     wrong:)
     
     It sounds like the performance of the gap you tried at Corby would 
     have been more improved by better heatsinking than variable speed 
     control . .
     
     for what it's worth
     
     paul


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Subject: dc rotary motor
Author:  Tesla List <tesla-at-pupman-dot-com> at INTERNET
Date:    6/6/00 9:44 PM


Original Poster: "bob golding" <yubba-at-clara-dot-net> 
     
Hi all,
    I have been thinking about rotary gaps. At Corby I tried Mikes asynchronous
gap on my big coil. I was impressed by the performance. I noticed that the 
spark length varied as the gap got hot. I want to try using a variable
speed dc 
motor and attempt to vary the speed to  get the Max spark length . I have a 
suitable motor I just salvaged from an old centrifuge. It is variable over a 
speed range of 0 to 5500 RPM,and is rated at 360 watts. I don't know how the 
controller will stand up to the RFI but I will no doubt find out soon
enough. I 
will try screening the electronics and maybe run the leads inside some
screened 
cable or something. anyone tried using a variable speed drive ? Any comments 
welcome.
     
     
cheers 
bob golding