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How does an electric meter work?
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Dan Lanciani
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How does an electric meter work?
In article .com,
(kevin) writes:
| So can anyone answer the op's original question? Does a mechanical
| meter overestimate when the load is imbalanced?
Yes, in the sense that the typical 4-terminal (1.5 element) meter most
often used in residential split-phase service charges the customer for
150% of the losses in the neutral on the utility's side of the meter.
(That's the simple case of one service drop from transformer to customer.
For multiple connections the analysis gets more complicated.) This seems
to surprise many people. Google for Blondel's theorem before trying to
come up with an argument that the meter does not make this error.
N.B. This has nothing to do with the meter's being mechanical. You can
build a 5-terminal (2 element) mechanical meter that does not have the
error. You can build a 4-terminal (1.5 element) electronic meter that
does have the error.
| And if so, can anyone
| think of a plausible scenario, in any possible situation, real or
| imaginary, that would let the device in the PDF picture (I can't tell
| what it is -- just some kind of metal C-shaped thing I guess) do
| anything that could even have a remotely possible chance of having even
| a miniscule, undetectable, insignificant but still non-zero effect on
| the meter?
I certainly can't.
Dan Lanciani
ddl@danlan.*com
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