[Prev][Next][Index][Thread]

Re: pole pig chart (fwd)





---------- Forwarded message ----------
Date: Sat, 25 Apr 1998 14:26:57 -0500
From: "Barton B. Anderson" <mopar-at-mn.uswest-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: pole pig chart (fwd)

DJ,

Tesla List wrote:

> ---------- Forwarded message ----------
> Date: Sat, 25 Apr 1998 17:57:47 -0700
> From: djQuecke <djQuecke-at-worldnet.att-dot-net>
> To: Tesla List <tesla-at-pupman-dot-com>
> Subject: Re: pole pig chart (fwd)
>
> It appears kVA just another unit for stating wattage that is easier to use
> at high voltages.

Not so. VA(voltamps) is a unit reflecting "apparent power" where W(watt) is a
unit reflecting "real power". VA is used on transformers when inductive loads
cause a phase shift which affects the power factor (a ratio of apparent power to
real power) and more importantly, allows the power company to spec in the right
transformer for the job. A power factor of 1 is desired but inductive loads can
lower this power factor depending on the degree of phase shift. With a power
factor of 0.5, 200VA = 100W. To get the power factor back to a unity of near 1,
power factor "correction capacitors" are connected across the source to draw
leading current from the source. However, regardless of this, it has been stated
that in a TC circuit, the power factor is near 1 and therefore, the VA can be
assumed close enough to real power (I have yet to prove this to myself - one of
those areas I want plan to see for myself). Maybe others could comment on this.

Bart