Re: Energy vanishing into air? (fwd)

[Steven Roys <sroys@xxxxxxxx>]

---------- Forwarded message ----------
Date: Sat, 17 Jan 2004 21:08:34 -0800
From: Richard Hull <rhull@xxxxxxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Re: Energy vanishing into air? (fwd)

The age old story played over again.  By theory, the voltage would rise to
infinity at the 0uf point, but long before then, in the real world, it would
corona away in the form of heat and EM radiation.  This is for plates being
pulled apart in air.  Steve is correct in that you would have to apply
mechanical energy to overcome the coulomb force, but that would be
additional energy you would need to put in to mechanically move the system
under ES tension.

The energy stored in the plates would just move out into space as EM
radiation.  There would a vastly different outcome if you had a bulk
dielectric between the plates.  A significant fraction of the energy would
remain in the polarized dielectric.  The capacitor plates and dielectric
could be mailed in three different packages and reassembled later and you
would still get a loud snap or the shock of your life.  Energy here was
stored in the bulk polarized dielectric.

Richard Hull


----- Original Message -----
From: "High Voltage list" <hvlist@xxxxxxxxxx>
To: <hvlist@xxxxxxxxxx>
Sent: Saturday, January 17, 2004 1:19 PM
Subject: Energy vanishing into air? (fwd)


> Original poster: Steven Roys <sroys@xxxxxxxx>
>
>
>
> ---------- Forwarded message ----------
> Date: Sat, 17 Jan 2004 11:54:14 -0500
> From: Alfred Erpel <alfred@xxxxxxxxx>
> To: High Voltage list <hvlist@xxxxxxxxxx>
> Subject: Energy vanishing into air?
>
>
>
> Howdy All,
>
>     Imagine an air variable capacitor with plates fully engaged and the
> capacitor fully charged.
>
>     Let's use the example of .001µF charged to 10,000 volts. Stored energy
=
> joules = .5CV^2 = .05 watt=seconds.
>
>     What happens to the energy of the fully charged capacitor when the
> plates are rotated to the 0µF capacitance position?
>
> Regards,
>
> Al Erpel
>
> [Potential energy.  It would take that much energy to rotate the cap
> plates to the 0uF position (barring friction losses), and rotating them
> back would convert the energy back from potential to the energy stored in
> the electrical field.  SRR]
>
>