Re: SRSG motor - HELP!!!!!

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "G by way of Terry Fritz <twftesla-at-qwest-dot-net>" <bog-at-cinci.rr-dot-com>

I too can confirm that the induced emf can cause flashover and 
failure in the motor windings. I had one motor fail that way, 
including a nice 1/4" melted section in the winding. I spliced it 
back together, added an emi filter, and rerouted the line cord 
farther away from the primary circuit. All has been well since!

I also noticed sometime later a carbon buildup between the AC plug 
hot/neutral; I shudder to think what I had been injecting into the AC 
line to arc across the plug surface.

Good luck,
Gregory

>Tesla list wrote:
>
>>Original poster: "Mr Gregory Peters by way of Terry Fritz
><twftesla-at-qwest-dot-net>" <s371034-at-student.uq.edu.au>
>>
>>Hello all,
>>
>>Today I was running my coil and getting solid 8 foot arcs, when
>>suddenly, and rather destructively, the SRSG motor died.
>>
>
>snipperzz..
>
>
>Hi Greg...
>
>by chance, did you have the cord which feeds the motor a bit long and
>was it coiled up to make things tidy? and was it in close proximity to
>the primary ( a few feet ?? )
>
>I has modified a motor from a Sears bandsaw to use as my SRSG and it ran
>very well for quite some time ( never got hot, warm but no hotter than
>normal use as a bandsaw) . I had set my coil up and used a different
>extension cord ( a bit long) and coiled up the excess cord and hung the
>excess on the lower part of the cabinet. After about 2 minutes of
>running, POOFFF  the motor smoked and died rather quickly. An autopsy of
>the motor showed that the windings in one spot had arced to the rotor
>and there was also arcing from the rotor to the bearings to the case...
>  seems strange that 120 volts could arc across 1/4" of air to the rotor
>from the windings in the case... 
>
>my only assumption was that the excess extension cord coiled up in close
>proximity to the primary was enuf to induce a fair amount of voltage in
>the cord from the primary field...   thus finding its way to the
>"grounded" rotor via the bearings and motor housing.
>
>something to think about......
>
>
>Scot D



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