3-phase monitoring and voltage

Hi

I have 3 phase monitoring+ voltage emontx in garage. I coded one temp sensor in that code

Now when CT-sensors are arrow towards the main switch I got negative readings in 2 phases. These could be rotated if wrong  but still when putting 2800W heater in one phase my meter shows 1300W. I know this because i got energy meter before heater.

Voltage is now calibrated with true rms meter to ~230V. I think i cannot calibrate that much in Ical values?

What I am missing here?

2. I got s0 output in my warmpump power meter. That is now connected to second emontx. It is working quite ok but sometimes there is a huge spike to positive or negative(readings out of scale). Perhaps when the time between pulses are too long? Have anybody fxed this in the pulse code or how to ignore bad data in emoncms(average?)?

Thanks again!

Robert Wall's picture

Re: 3-phase monitoring and voltage

Confirm your supply is 50Hz?
Have you tried to follow the calibration procedure in the comments at the top of the sketch?
Have you calibrated L1 - the phase that you are measuring the voltage of - for current and phasecal?
Have you got your phase rotation correct?
When you measure your phase-neutral voltages, are they similar, or is there a big difference?

The sketch works by recording the voltage wave for L1, then playing it back 1/3 cycle later to calculate the power for L2 and 2/3 cycle later to calculate the power for L3. If you are using the voltage intended for L2 with the current for L3, then the power will be very wrong.

You can set Ical1 ( for L1 ) by adjusting for the correct power, but with this sketch you should not use power to set the value of Ical2 and Ical3 , you must use the current itself, either use another clip-on ammeter or the load whose current you measured using L1. (This is because the phase angle error could be very large until you have correctly set phasecal2 and phasecal 3 and if necessary the array elements with "#define PHASE2 8" and/or "#define PHASE3 17" ).

I cannot help you with the emoncms problem. Someone else?

Tomis's picture

Re: 3-phase monitoring and voltage

Thanks again Robert.

My mistake..The AC-AC adaptor was on phase3. Now I changed it to phase1 and I started to get positive readings and power is around the right scale.

 

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