# Another to check voltage?

So I installed a reference voltage adapter (well, an uncorrected 9V AC one)

But they are huge,and require a GPO nearby. Australian are pretty big.

It’s not very feasible to have more GPO, one on each phase around my switch board.
I have just no room in there

.

Are there other means to measure voltage, taking much less space?
Thanks.

Yes, you can do three phase with one VT using derived reference. https://docs.iotawatt.com/en/master/threePhase.html

Thank you for your answer. This is what I’ve done so far (BTW, very confusing that the phase where the VT is plugged is phase A, got me)

However, I noticed a fairly large variation on the voltage between phases. close to +/- 2.5V. which I believe wouldn’t be detected in the derived mode.

In Oz we’re supposed to be at 230V +6% -2%, but I’m seeing 249V and it’s not even sunny (our distributor bump the voltage on hot day to help all the folks with their A/C)

Side question, how is pf calculated on the derived phases?

Would it help if IoTaWatt designated the phases as X,Y, and Z? The point is that it’s a circular relationship and they are all relative.

I would estimate that 90% of the three-phase users use derived reference, and Australia is one of the largest groups.

It’s hard to increase the voltage selectively on one phase. If the voltage is increased, it should be proportional on all of the phases.

Same as on a single phase:` real power / apparent power`. I should note that while voltage can vary, phase does not in any appreciable way. Shifting by +/- 120degrees is pretty accurate.

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