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daestrom wrote:
> Apparently you don't understand how a 'dumb' transformer works. It has no
> voltage sensors, it is a strict ratio device. If 600V in gets you 240V out,
> then 570V in will get you 570*(240/600) = 228V out.
I do know that, I didn't mean "iron core" dumb, I just meant
"non-electrically programmable by the utility control room"dumb. My
mistake for not being clear.
> But there are larger substations with load-tap changers that *will* adjust
> for variations in input voltage. These devices are set locally and are not
> under the direct control of the system operator. So they *would* adjust
> their turns ratio to try and compensate. Such devices also have a time
> delay built into them to avoid excessive stepping back and forth when a
> large surge takes place.
Smaller versions of THOSE type I'm familiar with. Alot of scientific
instrumentation I've worked on required those to make an absolute
output with varying input. Usually they tended to be a rock-steady 240
output from 208-ish input. So they would "try" to make 240 all the
time, whatever the building mains did, and if the mains didn't vary
overmuch, they did it.
> Perhaps the test was more to see how industrial and other high-voltage
> customer loads would vary with voltage. Not those downstream of
> regulators/tap-changers, but the high power consumers that draw right from
> the higher distribution voltages.
My thinking as well, poorly put by me. The industrial work I used to do
usually involved stuff like 4kV turbine air compressors and the like.
I'd have to figure that the utility doesn't output 240v, so if the OP
was monitoring it, it had been through a few stepdowns before getting
to him.
DJ
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