# wrong measurements

hello !
i've got 2 Fluksos installed :
1: over all power consumption with 3 sensors on 3 phases
2: only Heatpump with 3 sensors on 3 phases

so in the total consumption ( red ) the Headpump ( blue ) included
see attached diagramm

one can see clearly the curves going up and down, but the Heatpump consumtion is displayed to little.
I've measured the typical Headpump consumtion with a ampere metre : 7,2, 7,5 amd 7.6 Amps.

what can be wrong ?

many thanks

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###### bazzle | Fri, 10/01/2014 - 17:53

Are the phase voltages set correctly on the sensor setup page (assuming your using current clamps)

###### claib | Fri, 10/01/2014 - 18:47

yes : i'm using current clamps, and strange : the voltages are set correctlly : Flukso 1 and 2 are set to 230v

regards
Christoph

###### claib | Fri, 10/01/2014 - 19:43

checked as well that i have all clamps as 50A model :-)
- installed correctly

strange !

###### Fluc | Fri, 10/01/2014 - 23:18

In your calculation above, you wrote : 7,2, 7,5 and 7.6 Amps means about 5Kw in total.
Is it not P = U x I x root 3 or 230 (V) + 7,433 (A) (mean of 3 currents) x 1,73 = 2957,6 W ?
You multiply each current separate with the tension and all 3 together:
7,2 x 230 + 7,5 x 230 + 7,6 x 230 = 5129 W

###### claib | Sat, 11/01/2014 - 07:13

hmm
have you had a look on the diagram attached ?
the heatpump is alone connected to 3 fuses i attached the clamps

thx !

###### gebhardm | Sat, 11/01/2014 - 10:44

May depend also on how the heat pump (I suppose there is a three phase motor of the compressor) is connected; you assume that all phases "pull" against ground/neutral; that may not be the case as a three phase motor may be connected differently (refer to "star/triangle" or "YD"), thus pulling not against ground but against another phase; then the assumed 230V (of one phase against ground) do not match the required calculation. What does the manual of the heatpump say about its expected consumption? 5kW would be a lot as the heat efficiency of a het pump is enourmous...

###### gebhardm | Sat, 11/01/2014 - 11:54

To maybe get a structured analysis (actually repeating Fluc's post), I just had a look:
Power with symmetrical load in a three-phase current system is
P = SQRT(3) * U * I * COS(phi)
In a star connection Iline = I, Uline = U/SQRT(3)
In a delta connection Uline = U, Iline = I/SQRT(3)
With above values we get
Star: P = 1.7321 * 400V * (7.2+7.5+7.6)/3 * 1 = 5150W (averaging the currents measured); Uline = U / SQRT(3) = 400V / 1.7321 = 230V
Delta: P = 1.7321 * 230V * (7.2+7.5+7.6)/3 * 1 = 2961W
In the diagram we see in the blue line a total power value of around 3700W when the heatpump is working which would give a measured 5.4A per phase instead of the "directly measured" 7.4A per phase. So, now let's search for the missing 2A. With 2A we get 0.11V at the AVR, so any rounding problem on the FLM-side should be ruled out and the current clamps are accurate enough.
So, where is the error in reasoning (or still in the measuring)????

###### claib | Sat, 11/01/2014 - 19:19

hey there ; many thanks for the interresting discussion !
triple checked the installation and setup.

measured the total consumtion as well :

10.93 A = 2507W
9.82A = 2258W
11.6A = 2668W

total 7433W
Flukso says 7900W

i can live with that margin :-)

measured Heatpump consumtion ( included in the total ! )

7.02A = 1615W
7.31A = 1681W
7.5 A = 1725W
total 5021W
Flukso says 3230W

i can not live with that margin :B

i understand and can follow the Delta / Star discussion, but in this case i think it does not explain the phenomena :-)

best regards
Christoph

###### gebhardm | Sat, 11/01/2014 - 19:49

So in the end the question remains why the FLM measures only 5A where you measure 7A... Bart or any other electrical engineer, please share your wisdom with us puzzled nescient ;-)
@CLaib: Just out of curiosity; did you change from total to three-phase overview once to gain a view on the three-phase consumption separately? There is a thread where another Fluksonian says that update seems to have messed up the config... (what still would be strange)
Kind regards, Markus

###### claib | Sat, 11/01/2014 - 21:55

evening :-)
yes i changed the 2 Fluksos to 3 phases and 3x1 several times.
do you think i should do a hard reset ?
- i don't care about the datas.

best regards
Christoph

###### gebhardm | Sun, 12/01/2014 - 10:43

I would assume that no reset is required as flukso.net should "react" on the config change directly; what is the reading? Do the single phase measurements match "better"? Your chart in this portal's dash board still shows the combined values of each FLM; what does the minutes graph show you locally? Alternatively use a MQTT client to have realtime data...

###### claib | Sun, 12/01/2014 - 13:46

strange :
dissociated the 3 in one phases : first it ran, then 2 streams disappeared...
see attached diagram.

thanks

###### gebhardm | Sun, 12/01/2014 - 17:32

OK, strange; if "disappear" means "no value" then this I would see as correlated to the time when the heatpump is not working, what matches your initial diagram (like a refrigerator that is actually also just "visible", if it is compressing). If blue/yellow/green are associated with the heatpump, we may get nearer to the cause. Blue is in a proper range (ca. 2kW matching the 7.5A * 230V), but green and yellow then are much too low. All 50A clamps? Not two, the green and yellow (by whatever reason) 100A? At least "just two" clamps deliver a too low value corresponding to your initial measurement.

###### claib | Sun, 12/01/2014 - 19:34

ok ok : now the hard tour :-)
i placed the 3 and 3 clamps on the same phases to check.
so 2 clamps on phase 1, 2 on phase 2 and 2 on phase 3
ans see the difference !
what went wrong ?

###### claib | Sun, 12/01/2014 - 19:37

so infact i v'e got 2 fluksos in parallel
wich one should i trust ?

###### gebhardm | Sun, 12/01/2014 - 20:57

WP1 shows IMHO too low values; as seen in your second diagram corresponding to your measurements the delivered values of two clamps do not match/are too low; again question from the very beginning: In three-phase mode, are all voltages the same? Cyclically change the clamps and see if the "error moves" also; a peak of in total 12kW is somehow startling also...

###### claib | Tue, 14/01/2014 - 14:53

replaced the 3 clamps : still got them in parallel : see the attached diagram : now it matches perfect !
will one set back to the heatpump now.

###### claib | Tue, 14/01/2014 - 14:57

would it be possible to erase the wrong history datas ( WP1 ) on Flukso FL03001627 ?

thanks

###### claib | Tue, 14/01/2014 - 15:24

claps for the Heatpump back in place again ( 3 clamps replaces by new ones )
see the diag's in the attachements

###### claib | Thu, 16/01/2014 - 07:05

end of latin :-)
changed the clamps and the Flukso device : i'm back with the old values showing a much to small power consumption of the heatpump...

many thanls for the help
Christoph

###### icarus75 | Thu, 16/01/2014 - 11:48

Hello Christoph,

I've just checked the configuration of both FLMs. Your FLM02B, i.e. the one measuring the heat pump, reported a synchronisation error to flukso.net. I've re-synced and that issue seems to be solved.

Let's try to pinpoint the issue:
1/ Could you put the FLM measuring the heat pump into single-phase mode so that it reports the phase readings individually? Then, if physically possible, attach all three clamps to the same phase. This is just to check each of the clamps/inputs of the FLM are reporting similar readings.
2/ You've probably checked and double-checked this: Are you sure you've attached the clamps to each of the three phases? And not identified neutral as a phase?
3/ I'm assuming the heat pump is indeed a 3-phase pump (3x400V with N)?

That's all for now.

Chees
/Bart

###### claib | Thu, 16/01/2014 - 17:18

Hello Bart

thank you so much for the answer
the compressor is in fact 3X400 V :-)
so we are getting closer....
What i do not understand is that the total consumption ( including the branch with the Heatpump )
does not show the total consumtion minus rest minus HP.
never the less : should i adjust the voltage for the HP clamps ?
the " official " Power consumption of the HP should be 4.3 Kw ( Datasheet )

best regards

Christoph

###### Fluc | Fri, 17/01/2014 - 00:54

The official Power consumption of the HP following the datasheet is 4.3 Kw, yes, but is that not the maximal power. I can be wrong, but i think your consumption shall be less, lets say between 3.5 and 4 Kw.

###### claib | Mon, 20/01/2014 - 08:44

hello :-)

now i've set the clamp voltage of the Heatpump to 400v, and the diagram makes sense !
- see the last attachement.

what do you think ?

many thanks