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Re: [TCML] Secondary and Primary Assistance

In a message dated 3/18/08 1:36:10 P.M. Eastern Standard Time,  
resonance@xxxxxxxxxxxx writes:

>Be sure to get the double-build magnet wire.  It handles the  higher turn to

>turn voltages better --- these potentials are much higher than an  electric

>motor which usually uses single build  wire.

    Electric motors *aren't* usually wound with single  build wire. At least 
not name-brand American integral-horsepower three-phase  motors. NEMA MG-1 
specs call for the insulation to withstand 1600 Volts on  inverter-duty motors. 
With the advent of IGBT-switched inverter drives in the  past 15 years, motors 
have had to suffer increased stresses from the fast  switching times. Failures 
occur because of corona inception between phases,  mainly at the end turns 
outside of the stator slots. With longer cables from the  drive to the motor, 
turn-turn voltages deep within each winding can easily  exceed 2000 Volts with 
every switching event!
    In a typical Tesla coil that produces 500,000  volts peak top voltage, it 
will probably have 1000 turns. That works out to  around 700 volts per turn. 
In a message dated 3/18/08 2:10:15 P.M. Eastern Standard Time,  
Gary.Lau@xxxxxx writes:

>DC, I've heard you say over and over again to use only double-build  magnet 
wire to ensure against 
>turn-to-turn arcing. 

    In DC's defense, that's not the only type of wire  he's advocated. In 
several posts:
    he recommended using silver-plated copper wire with  Teflon insulation. 
Serious, expensive stuff (and very hard to varnish!). 

-Phil LaBudde
Center for the Advanced Study of Ballistic  Improbabilities

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