idea to let the flukso measure voltage

by waaij on

Hi all,

Just an idea to let the flukso also measure the voltage of the signal to calculate more corretly the power usage.

What if we would replace the power adapter of the flukso with an AC adapter (transformer, say 230:9 volts). Use a couple of diodes to make it a DC signal to power the flukso and probably a voltage stabeliser. Then use one of the analog inputs of the sensor board to measure the (flukso's own) AC adapter input signal. This value ofcourse must be corrected for the transformer proportion 230:9 volt. It seems to me that the voltage sinus singal is the same everywhere in the house as on the spot you use the flukso clamps. I am not sure if it is possible to use the analog inputs the measure the voltage of the device itself. Perhaps an optical interface is needed, to create a galvanized separation.

Anyone any thoughts on this?

Best regards,
Bram

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icarus75's picture
icarus75 |

Hi Bram,

Although not straightforward, your idea should be possible to implement. Here are some hurdles I can think of instantly:
1/ A 'pure' current transformer without any rectification, as is currently the case, would be required. Both inputs, proportional to instantaneous voltage and current, can then be fed to an A/D channel which then performs a multiply-accumulate calculation.
2/ Even better, a dedicated energy measurement IC could be used, e.g. MCP3905.
3/ For a precise measurement, the phase shift occurring in the current and voltage transformers should be small.
4/ Safety would need to be properly addressed. A big plus of the current Fluksometer is its complete galvanic separation from the power circuits it's measuring on it's analog as well as digital inputs. In case of the digital ones, this is taken care of by an opto-coupler inside the DIN-rail energy meter.
5/ The solution will not work for three-phase installations, leaving a significant fraction of households in the dark.

Cheers,
Bart.