[Prev][Next][Index][Thread]
Re: Re[2]: Neon power draw, was Yet another newcomer, and from Sweden this time
From: FutureT-at-aol-dot-com[SMTP:FutureT-at-aol-dot-com]
Sent: Thursday, August 28, 1997 4:01 AM
To: tesla-at-pupman-dot-com
Subject: Re: Re[2]: Neon power draw, was Yet another newcomer, and from Sweden this time
> For 12 kv 30 ma, when arcing, I measured 3 to 4 amps input; in other
> words, my neons are quite efficient. This is presumably thanks to their
> containing capacitors inside for power factor correction, otherwise
> they'd have to draw more current for the same output.
> You might consider heavy-duty high-wattage resistors, i.e. light bulbs,
> as a cheap substitute for variacs. The limitation of bulbs is that their
> initial (cold) resistance is low.
>>
Felix, All,
Another consideration when selecting a variac for a neon sign
transformer, is the size of your capacitor. If it's value is such
that it resonates with the leakage reactance of the neon trannie,
then the trannnie will draw more than its rated power even when
PFC caps are used. For example, my 12kV, 30ma trannie, with
PFC caps, draws 680 watts. The coil gives 42" sparks. Using
a correctly sized cap is the key to obtaining long sparks from a
NST driven TC. I used .007uF in this case.
John Freau