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Re: VAR
Tesla List wrote:
>
> >From pierson-at-msd26.enet.dec-dot-comSat Jul 13 22:05:03 1996
> Date: Sat, 13 Jul 96 17:52:49 EDT
> From: pierson-at-msd26.enet.dec-dot-com
> To: mail11: ;
> Cc: pierson-at-msd26.enet.dec-dot-com
> Subject: VAR
>
> >Richard Hull, TCBOR
>
> >AC watts are volt-amps in a purely resistive AC circuit (like frying a
> >human being.) But not in Tesla coil power circuitry. the correct term
> >is VAR, volt-amps-reactive.
>
> >This tells the listener that a simple current and voltage measurement was
> >taken in an AC circuit with known reactance present, but without a phase angle,
> >tells little more.
>
> Uhmmmmm. That may be the way the term VAR is used in the Tesla Field.
> Electrical engineers asign it a more specific meaning. VAR is
> DEFINED AS the '90 degree' value. That is if a cap or inductor
> (neglecting resistance) is thron on line it draws ONLY VARs.
> (in fact, systemc ontrol boards have 'VAR meters' to aid in setting
> up PF correction caps. In fact PF correction banks are commonly rated
> as '<mumble> VAR' banks.
>
> So with a complex load, there will be:
>
> WATTS == in phase power.
> VA == Volts times amps == greater than WATTs
> VAR == VOLTS times AMPS at 90 degrees (imaginary).
>
> WATTS being defined as tue power and VAR as 'imaginary' power, the
> vector sum should match VA.
>
> ('imaginary' has a specific meaning in electrical engineering. I
> would guess most of the list members are familiar with this, but a
> few may not be...)
>
> regards
> dwp
You are correct! Var is for purely reactive components and is at + or -
90 degree phase angles. I have used it rather loosely in my post and
apologize to all. Most Tesla circuits are inductive in reactance as
appearing to the AC line and run a positive power factor angle. A tesla
circuit might be reduced to an equivalent pure inductance on the line
rated in VARS and you would then need a capacitor of the same VAR rating
to correct to zero phase angle or PFC. Sorry about the lack of calrity.
Richard Hull, TCBOR