RE: Arc Welders as Rheostats??

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

Original poster: "Loudner, Godfrey by way of Terry Fritz <twftesla-at-qwest-dot-net>" <gloudner-at-SINTE.EDU>



> -----Original Message-----
> From:	Tesla list [SMTP:tesla-at-pupman-dot-com]
> Sent:	Sunday, March 24, 2002 11:13 PM
> To:	tesla-at-pupman-dot-com
> Subject:	Re: Arc Welders as Rheostats??
> 
> Hi Chris
> 
> Since the e-mail I sent you keeps bouncing back as undeliverable, I'll
> have to answer your questions on list.
> 
> For power companies, the primary is the 13,200 volt side (high side) and
> the secondary is the 120/240 volt side (low side). For tesla coilers, its
> just the opposite. 
> 
> The kVA of your pole pig is the amount of power the transformer can handle
> continuously without over heating. Since pole pigs are overbuilt, your
> transformer can handle more than 25 kVA for short periods of time. Power
> is the amount of energy that is produced or consumed per unit of time.
> Power = Voltage x Current. Power, voltage, and current are measured in
> watts, volts, and amperes respectively. 25 kVA = 25,000 watts. Here k
> stands for 1000 and VA = volt x ampere = watt. Then Current = Power /
> Voltage. If 240 volts is applied to the low side and the pole pig is
> processing 25 kVA of power, the current on the low is is (25,000 / 240)
> amperes = 104 amperes. Also the current on the high side is (25,000 /
> 13,200) amperes = 1.9 amperes. A milliampere (mA) is 1/000 of an ampere.
> So  1.9 amperes = 1900 mA. A big neon sign transformer (NST) is rated at
> 60 mA. Currentwise, the possible 1900 mA output of your pole pig is
> equivalent to the combined current output of 1900 / 60 = about 32 of the
> big NSTs. The above accounrt of kVA can be made more technical (inductance
> and complex numbers), but I think this is good enough for someone who
> wants to build a pole pig system. I hope this will clear up your math.
> problems. 
> 
> The short circuit current (low or high side) of your polr pig would be
> very high. This can be determined, assuming an infinite source of
> generated power, from the impedance of the transformer which is listed on
> the rating plate. But this is a useless calculation for tesla coilers.
> Power companies need to know this so they can determine breaker or fuse
> ratings. 
> 
> Godfrey Loudner   
> 
> 
> 
>