I am looking for a 220 volt variac.

Does anyone have such a beast?

Thanks!

Fred
WA4PAV

"Fred Cameron" wrote in message
...
I am looking for a 220 volt variac.

Does anyone have such a beast?

Thanks!

Fred
WA4PAV
Hi Fred,
I have a nice 220VAC @ 10A that I no longer need. It was originally used
for my 1296 EME amp, but I have now built a hi power solid state amp. This
is
a Warner Electric 236B. Although currently wired for 110VAC, it is a 220VAC
unit. I can supply connection drawings with the variac. Very nice condition.
Make an offer if interested.

Dale W4OP

On Jul 11, 10:18 pm, Fred Cameron
wrote:
I am looking for a 220 volt variac.

Does anyone have such a beast?

Thanks!

Fred
WA4PAV

On the basis that a transformer, In this case a variable tap auto-
transformer, is an electromagnetic device:
Question: Could one not input the variac with say 230 volts instead of
115 volts.
Then at, say, 20% dial setting the output would be 46 volts and at
100% it would be 230 volts. Etc.
As long as the current and total power transformed are within the
ratings of the variac, would it matter?
After all transformers, either those with separate input and output
windings, tapped or untapped, or auto-transformers can be used to step
voltage up/down and so forth.

terryS wrote:
On Jul 11, 10:18 pm, Fred Cameron
wrote:
I am looking for a 220 volt variac.

Does anyone have such a beast?

Thanks!

Fred
WA4PAV

On the basis that a transformer, In this case a variable tap auto-
transformer, is an electromagnetic device:
Question: Could one not input the variac with say 230 volts instead of
115 volts.
Then at, say, 20% dial setting the output would be 46 volts and at
100% it would be 230 volts. Etc.
As long as the current and total power transformed are within the
ratings of the variac, would it matter?
After all transformers, either those with separate input and output
windings, tapped or untapped, or auto-transformers can be used to step
voltage up/down and so forth.

One could if the 120V variac was seriously over built. The problem is
if the variac was built using normal engineering practices, the turns
ratio would drive the core partially, or fully into saturation at 240V,
and it would at the minimum get very hot, and at the worse case, blow
the breakers.

-Chuck

terryS wrote:
On Jul 11, 10:18 pm, Fred Cameron
wrote:

I am looking for a 220 volt variac.

Does anyone have such a beast?

Thanks!

Fred
WA4PAV


On the basis that a transformer, In this case a variable tap auto-
transformer, is an electromagnetic device:
Question: Could one not input the variac with say 230 volts instead of
115 volts.
Then at, say, 20% dial setting the output would be 46 volts and at
100% it would be 230 volts. Etc.
As long as the current and total power transformed are within the
ratings of the variac, would it matter?
After all transformers, either those with separate input and output
windings, tapped or untapped, or auto-transformers can be used to step
voltage up/down and so forth.


The basic transformer design equation is:

E = 1.4*f*N*B*A,

E = primary voltage
f = frequency
B = Flux Density [typically 80% of Bmax]
A = Cross sectional area of core.

B is a non linear response of the magnetic material. It become 'flat' as the
core saturates and the current increases DRAMATICALLY.

Since f, Bmax and A are fixed for a 120 VAC design, applying 240 VAC to the
primary will 'fry' the variac and your hand, and pop the circuit breakers for sure.

Now, a 240 VAC design can be run at 120 Vac, but not vice-versa.