Rick wrote:
couldn't possibly be right - we all know that condensers are 100%
efficient and coils are lossy - right?...


Good work. Congratulations on doing some real experimenting and thanks for
reporting.
What do you attribute the losses in the cap to? Could it be contact
resistance between the plates and the rotor? Would it be possible to
substitute some commercial cap temporarily to compare?

Rick K2XT



Show me a 100% efficient cap first, then I will show you where to patent
it and sell it. You will then have the money to purchase my bridge in
the desert!

Regards,
JS

John Smith wrote:
Rick wrote:
couldn't possibly be right - we all know that condensers are 100%
efficient and coils are lossy - right?...


Good work. Congratulations on doing some real experimenting and
thanks for reporting.
What do you attribute the losses in the cap to? Could it be contact
resistance between the plates and the rotor? Would it be possible to
substitute some commercial cap temporarily to compare?

Rick K2XT


Show me a 100% efficient cap first, then I will show you where to patent
it and sell it. You will then have the money to purchase my bridge in
the desert!

Regards,
JS

Of course, there must be lossless caps somewhere, huh? Because a cap
with no dielectric would suffer no losses (ignoring the resistance of
the plates to the inrush, exhaust of electrons), huh? So then, a cap
consisting of plates in a vacuum would have no dielectric and no loss.

Strange, I seem to still notice a loss in such a device when examined
mathematically. Perhaps the ether is serving as a dielectric?

Chuckling,
JS

John Smith wrote:
Of course, there must be lossless caps somewhere, huh?

There's some in EZNEC. :-)
--
73, Cecil http://www.w5dxp.com

Well, there are dielectrics and there are . . . ummm well you get the
point...

In this case the main dielectric of my condensers is glass, probably
stannous float bath soda glass... 0.100" thick with an aluminum plate
on each side... After my fingers had found the disparate temperature
rise on an early test I did a literature search for the dielectric
constant and loss factor of glass and discovered that not all glass is
equal - or as Orwell put it, some of the animals are more equal than
the others...

Anyway, Soda glass has a loss tangent of 0.01 to 0.05 and a dielectric
constant of 6 - and Borosilicate glass (Pyrex) has a loss tangent of
0.001 to 0.002 and a dielectric constant of 4... So, it would appear
that Borosilicate glass is better as a low loss dielectric... The
trade off is that with 1/3 lower Dielectric Constant I would have to
increase my plate areas by 1/3 to maintain the same capacity... The
jury is out on this... 3.5 mc is relatively low frequency... I am not
sure how much of the heating is due to the loss factor of the glass and
how much is I2R heating from the current flowing across the plates...
I spoze I could order some custom made 8" X 10" X 0.100" Pyrex plates
and compare otherwise identical condensers... OTOH, I spoze some of
the more equal animals in my house would complain over sticks and
stones in their xmas stockings after I pay for the Pyrex...

denny / k8do

stannous float bath soda glass...

Denny

Please, what is this? stannous float? something to do with tin?

Thanks

John
AB8O

"Denny" wrote in message
ups.com...

Well, there are dielectrics and there are . . . ummm well you get the
point...

In this case the main dielectric of my condensers is glass, probably
stannous float bath soda glass... 0.100" thick with an aluminum plate
on each side... After my fingers had found the disparate temperature
rise on an early test I did a literature search for the dielectric
constant and loss factor of glass and discovered that not all glass is
equal - or as Orwell put it, some of the animals are more equal than
the others...

Anyway, Soda glass has a loss tangent of 0.01 to 0.05 and a dielectric
constant of 6 - and Borosilicate glass (Pyrex) has a loss tangent of
0.001 to 0.002 and a dielectric constant of 4... So, it would appear
that Borosilicate glass is better as a low loss dielectric... The
trade off is that with 1/3 lower Dielectric Constant I would have to
increase my plate areas by 1/3 to maintain the same capacity... The
jury is out on this... 3.5 mc is relatively low frequency... I am not
sure how much of the heating is due to the loss factor of the glass and
how much is I2R heating from the current flowing across the plates...
I spoze I could order some custom made 8" X 10" X 0.100" Pyrex plates
and compare otherwise identical condensers... OTOH, I spoze some of
the more equal animals in my house would complain over sticks and
stones in their xmas stockings after I pay for the Pyrex...

denny / k8do

Could you use some Pyrex disk, I think I have some that are about a foot in
diameter. If I can find them they are yours for the postage.