[SOLVED] - 3x400+N setup (Belgium) and unreliable readings
by on
Hi,
I've had my Flukso FLM02a for over half a year now, but I can't seem to get accurate electricity measurements out of it. I also measure water usage via pulses - and that works like a champ!
We have a 3-phase setup at home (3x400+N), and so I'm using 3x 50A clamps on the phases.
I had initially configured the setup as 3 clamp ports, 1 phase - in order to make sure I had valid measurements of each phase (initially one wasn't registering at all - badly cabled). I had also set the voltage at 230V/50Hz, which I think is correct for my setup (I measure ~230V between a phase and N, and ~400V between phases).
Most usage in our home can be attributed to single-phase devices : our 150L water boiler, washing mashine/dryer, microwave, etc. In fact the only 3-phase device we still have is our oven (we used to have a water pump).
Regardless, I wasn't getting good values at 230V. I first checked and double-checked the cabling, but it looked good - and was providing measurements. Then I had an idea: since voltage seemed to be the only variable I could influence in the configuration, I played with it a bit until the power values were more reasonable (I know the wattage of most devices via my Plugwise setup, for example our boiler is currently just under 1kW). But the total still seemed off...
So, last week I had figured: why don't I calibrate the voltage per phase (still assuming it could be used as a correction factor... but I'm obviously no electrician!)... and I took a fan heater, measured it to be sure the power was more or less constant (1166W), and tweaked the voltage sensor config on each of the 3 phases until the flukso was also showing that power usage [delta] on every phase. I ended up with 383V (phase R), 275V (S), 455V (T). I don't know if my line of reasoning here is correct...
Then I wrote down the electricity counter at midnight last night, and again today at 20:45 - with the intention to compare with my Flukso's readings.
Boy was I disappointed: my meter measured 60333,2 - 60315,8 = 17.4 kWh for that period, and Flukso, using "Wh [cumulative]", measured RST values (2266+6832+2520) - (2+0+62) = 11,6 kWh. Another giveaway that the measurements were off here, looking at the Dash: our 1kW boiler on phase S (>7AM) is showing only 700W.
Oh, and one more oddity on Phase S : although most of our bulbs are CFL bulbs - I have a few incandescent bulbs (pf=1?). Turning on 3 of them (180W) - doesn't even show as much as a blip (using Energy Control on Android to visualise the instant power use). I've not tried this on the other phases, but our TV setup on another phase does register.
Does anyone have any advice for me? Is my Flukso faulty? Is my cabling faulty? Are my assumptions faulty?
Thanks for any tips!
- Gerrit
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[UPDATE 27/1/2013]
OK, so it turns out my clamps were not completely shut (see comments). I leave the above for reference - but it's all based on a bad installation!