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- To: mail11:;;;;;-at-us4rmc.pko.dec-dot-com-at-us4rmc.pko.dec-dot-com-at-digital-dot-com;;;;;;;; (-at-teslatech)
- Subject: VAR
- From: pierson-at-gone.ENET.dec-dot-com
- Date: Thu, 13 Mar 97 15:03:26 EST
- Cc: pierson-at-gone.ENET.dec-dot-com
>> Thus the peak current which we might expect in the tank is based on the peak >> capacitor voltage and the surge impedance. Such that... I peak = 21,000/50 or >> 420 amps From this we compute peak impulse power = 420 X 21000 = 8.82 >> megawatts!!!!! >Shouldn't that be MVARs (Mega-Volt Amps Reactive), I wouldn't say so. I wouldn't say watts, either, tho. >as the V and I aren't in phase? Probably not. In conventional 'lectrical eng'g, Watts is reserved for Real Power, which means _knowing_ that the V and the I are In Phase. Here, we don;t know. Likewise, conventionally, VA is used for the product of Volts & Amps where the phasing of V and I is Unknown, OR is known & Specified. Some times VA equals W. Sometimes (most times) VA is greater than W, by some unknown amount. Conventionally, VAR (MVAR, if there are lots of them... 8)>>) Are DEFINED AS VA WITH A PHASE OF 90 Degrees. That is, pure 'imaginary' power. Pure inductive or pure capacitive load. A tesla coil is neither. (the technical term for such a load is 'complex'. OOOOOOOOOBoy is is complex...8)>>) It is tempting, as i said a few days ago, to think of the coil load (at the line side) as being 'highly inductive', i mean after all, we can SEE all those windings... I Suspect the actual is a little different. The tank is resonant, so L and C balance, more or less, leaving the power transformer looking at a (largely) resistive load. Likewise, the secondary is resonant, either physically, or lumped-parameter, or both, so THAT should 'look' resistive. So i bet the input looks a whole lot more resistive than might appear. I'd be real interested in some measured values as to how reactive the coil looks at the AC line input. I suspect that a coil 'just below breakout' is more resistive than expected. Once it breaks out, hmmmmm, dunno. Measure & see... Beats the heck out of any amount of guesswork. regards dwp
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