3 phase energy meter

i already told you
its too expensive
i am searching for cheaper solution
and i am sure that someone knows how to do it

when i find out i will also here publish it

Hi,
The Cent-a-Meter does not measure power directly.
It measures current but not voltage, this is set in the device.
In fact it is set at 240Vac, my mains can go higher to 250Vac and low as 225Vac.

I would agree with @MarkT, look at https://openenergymonitor.org/

Tom.... :slight_smile:

neznamnista:
i already told you
its too expensive
i am searching for cheaper solution
and i am sure that someone knows how to do it

when i find out i will also here publish it

Well, somebody posted a link to a current transformer for ~$8 shipped to the US. If this is too expensive for you to get started with your project, then find some scrap wire and wind your own current coil and do some experimenting. Like everything else there is usually no free ride.

I think somebody should come up with a way to breed a very large shrimp. That way, you could ride him, then after you camped at night, you could eat him. How about it, science? - Deep Thoughts by Jack Handy

Part of the cost of the CT is in the calibration you get with it.

An alternative is for you to make three Rogowski coils , seen here.

You do not need to disconnect the mains wiring to use them, but you still need calibration.

Paul

Esp8266
Current transformer
Resistores
Capacitor
Should be around 10 dollars.
When you find cheaper than that please do let us know

TomGeorge:
Hi,
The Cent-a-Meter does not measure power directly.
It measures current but not voltage, this is set in the device.
In fact it is set at 240Vac, my mains can go higher to 250Vac and low as 225Vac.

And as the voltage goes up, the current goes down so the wattage remains constant.

The cent-a-meter was never meant to be an accurate metering device, even Clipsal will tell you that. However I think it would be safe to assume the average would essentially be just that, average.
Power does fluctuate but if the degree you mention, I’d be getting some answers from the local authority. They will guarantee a supply within a variation of 5% which for the most part is fairly generous given the wide variations that can come about with supply authority infrastructure.

As for accuracy, the Op mentioned use in the home so basically a novelty device anyhow.

bluejets:
And as the voltage goes up, the current goes down so the wattage remains constant.

Why???
Take a heater or purely resistive load as an example.
If I was connected across 240Vac and it went to 250Vac the current through me would increase so power load would increase.
OHMS LAW.
I = V/R
P = V*I = I2 * R

Tom… :slight_smile:

TomGeorge:
OHMS LAW.
I = V/R
P = V*I = I2 * R

Tom… :slight_smile:

Power factor correction?

.
But you are correct for novice level we are recomending.

You show apparent power. That is found using just one CT.
that is the first step and does not waste any time money or effort.