Transformers - RE: supplying power to a color vector monitor

Actually, pretty much every post is right, just with different bits and pieces.

Transformers can take two basic forms: galvanically isolated (no
continuity or electrical conductivity between windings - isolated
essentially), and auto transformers (autoformers).

Galvanically isolated is nothing more than a fancy term for "separate
windings". Two or more electrically isolated windings with various voltage
ratios (linearly related to turns) and current carrying capabilities.

Auto transformers "share" parts of their windings with other windings,
making them inherently non-isolated. They tend to have benefits in
efficiency and size in some instances, but provide no galvanic (electrical)
isolation whatsoever.

All transformers can be "step up" or "step down" or both depending on their
winding configurations.

Also, do not confuse a muli-winding transformer with one or more "taps"
with an autoformer. Taking a basic transformer that has a voltage ratio of
say 1:1, you can "tap" one winding such that one of the leads on the
"tapped" winding can be moved providing ratios other than 1:1. This is
usually how the multi-voltage transformers are configured so they can be
jumpered (or "strapped") for the different international voltages. But in
any case, this type of transformer still provides electrical isolation from
the "primary" (in this case the line-side connection) to the
"secondary(s)". They also have to be designed to work on 50 and 60 hertz,
but that's a subject for another conversation.

Generally if there is continuity or sub-megohm resistance from the
transformers "primary" to it's "secondary(s)", it's not an "isolated"
transformer.

There are also ferro-resonant transformers that have a resonant capacitor
connected to one "secondary" in the transformer, like the MCR Midway games
used (and partly what made them so damned heavy), but that's yet another
animal and not at all vector related ;)

Brad

At 07:34 AM 7/3/2002 -0700, you wrote:
>Not all transformers are isolation. There are the step up/down
>transformers that one often sees in the Japanese and European video games
>to adjust the input voltage from 115 to either 100 or 220 VAC. So, it is
>quite possible to have a transformer in your junk drawer that is not isolation.
>
>John :-#)#
>
>At 09:00 AM 03/07/2002 -0400, James R. Twine wrote:
>
>> > From: Jon Raiford
>> >
>> > You didn't mention if these were isolation transformers and
>> > there was no link to check.. Neil, make sure you use an
>> > isolation transformer if you piece a replacement transformer
>> > together!!
>>
>> This may sound naïve, but I was under the impression that the term
>>"isolation transformer" simply meant a 1:1 transformer: a transformer
>>whose input voltage was the same as its output voltage.
>>
>> IIRC, the purpose of an isolation transformer is to *physically*
>>isolate the equipment from the power line, which all transformers do,
>>anyway: they work by inductance. So by using *any* transformer, you
>>would already get physical isolation...?
>>
>> Thoughts?
>>
>> Peace!
>>
>> > Jon
>>
>>[Get Check Favorites 1.4 Now! http://checkfavs.jrtwine.com]
>>-=- James R. Twine, MCP, (jtwine@jrtwine.com)
>>-----BEGIN GEEK CODE BLOCK-----
>>Version: 3.12
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>>------END GEEK CODE BLOCK------
>>
>>
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Received on Wed Jul 3 08:28:48 2002