dc rotary motor

["bob golding" <yubba-at-clara-dot-net> (by way of Terry Fritz <twftesla-at-uswest-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