I did so, and it works perfectly.
But you have to multiply the power resp. energy by 3 to get the correct 3-phase value.

You can try to change the voltage value of the software setting of the sensor clamp(s) to 3x230V = 690V to do so, but maybe there is a range limit for this input.

I clamped the sensor on tree windings of the 1-phase cable and did the multiplication easily by hardware.
Be aware about the current limit for the choosen clamp, because it has to manage a 3 times higher current.

Regards,
Stefan

gebhardm |

Hmmm, when I think of the phase-shift within the hot wires of a 3-phase motor I am not really sure what I would measure with one clamp alone; this youtube video on measuring three-phase current also lets me think... also I am curios what you refer to with multiplying three time 230V; shouldn't a 3-phase assembly be 380/400V when without reference to neutral/earth potential. I am a bit puzzled...

ryftes |

I'm not suggesting to use 1 clamp on all wires but that 1 clamp on one phase should always correspond to a 1/3 of the load!?

gebhardm |

This actually seems what Stefan suggests; the trick with the three windings through the clamp of the wire to measure then makes multiplication unnecessary.

ryftes |

My cables are 250 amps so i dont think winding is possible.

Uli_Markt_Schwaben |

Yes GebhardM, 1 clamp on one phase corresponding to a 1/3 of the load was excactly my suggestion.

Ryftes, your are also right: Hardware multiplication by 3 using 3 turns of this one wire going three times through the clamp hole is hardly to archive with non-flexible 250 amps wires; so software multiplication ist the best way.

You can archive a power-(resp. energy-) multiplication by 2, if you programm flukso to a 500 amp clamp allthough installing your 250 amp clamp.
You can archive another multiplication with factor 1.5 by setting the voltage value to a (wrong) value of e.g. 230V*1,5 = 345V (if flukso's web interface accepts this value)
Totally both corrections will result in factor 3 and the dash should show the correct power/energy consuption of the whole 3-phase motor and you will have saved the money for two clamps resp. two clamp inputs free for other devices.

ryftes |

Seems that you cant input 690volts as volt on one clamp.
neither is it possible to input 500amps and use 345volt.

----

sm 0 11916 .. nok .. should be sm 0 77452 instead
sm 0 11916 .. nok .. should be sm 0 77452 instead
sm 0 11916 .. nok .. should be sm 0 77452 instead
sm 0 11916 .. nok .. should be sm 0 77452 instead
sm 0 11916 .. nok .. should be sm 0 77452 instead
5 write attempts failed. Exiting ...

---

Another issue is that i have one cable that actually is 3 cables, i guess that instead of one 3phase cable someone desided that it was easyer to use 3 cables.
here i would like to use one clamp for one of 3 cables on one phase, so instead of multiplying by 690 i would like to multiply by 3*690....
And yes, one clamp for all 3 cables on one phase is not possible because one cable is 250A.

/Peter

icarus75 |

The second parameter in the sm command, which is directly proportional to the configured amps and volts, should be kept below 65k. What you're experiencing is an overflow condition on this parameter: 77452-11916=65536. The good news is that the FLM does proper boundary checking on the input parameters, the bad news is that you cannot use 690V with 250A. But you can still post-process your data to get correct readings.

ryftes |

I'm glad that FLM does proper boundarychecking.

What you are saying is that i'm forced to buy 3 clamps for each measurepoint to get the correct values in the database?!

/Peter

icarus75 |

Either that, or you extract the data from api.flukso.net and multiply each reading by 3.

An API solution will be mor costly in the longrun.
A solution with another box inbetween, alltough more accurate, will also be more expensive specially in the 250-500 amps range.

I did so, and it works perfectly.

But you have to multiply the power resp. energy by 3 to get the correct 3-phase value.

You can try to change the voltage value of the software setting of the sensor clamp(s) to 3x230V = 690V to do so, but maybe there is a range limit for this input.

I clamped the sensor on tree windings of the 1-phase cable and did the multiplication easily by hardware.

Be aware about the current limit for the choosen clamp, because it has to manage a 3 times higher current.

Regards,

Stefan

Hmmm, when I think of the phase-shift within the hot wires of a 3-phase motor I am not really sure what I would measure with one clamp alone; this youtube video on measuring three-phase current also lets me think... also I am curios what you refer to with multiplying three time 230V; shouldn't a 3-phase assembly be 380/400V when without reference to neutral/earth potential. I am a bit puzzled...

I'm not suggesting to use 1 clamp on all wires but that 1 clamp on one phase should always correspond to a 1/3 of the load!?

This actually seems what Stefan suggests; the trick with the three windings through the clamp of the wire to measure then makes multiplication unnecessary.

My cables are 250 amps so i dont think winding is possible.

Yes GebhardM, 1 clamp on one phase corresponding to a 1/3 of the load was excactly my suggestion.

Ryftes, your are also right: Hardware multiplication by 3 using 3 turns of this one wire going three times through the clamp hole is hardly to archive with non-flexible 250 amps wires; so software multiplication ist the best way.

You can archive a power-(resp. energy-) multiplication by 2, if you programm flukso to a 500 amp clamp allthough installing your 250 amp clamp.

You can archive another multiplication with factor 1.5 by setting the voltage value to a (wrong) value of e.g. 230V*1,5 = 345V (if flukso's web interface accepts this value)

Totally both corrections will result in factor 3 and the dash should show the correct power/energy consuption of the whole 3-phase motor and you will have saved the money for two clamps resp. two clamp inputs free for other devices.

Seems that you cant input 690volts as volt on one clamp.

neither is it possible to input 500amps and use 345volt.

----

sm 0 11916 .. nok .. should be sm 0 77452 instead

sm 0 11916 .. nok .. should be sm 0 77452 instead

sm 0 11916 .. nok .. should be sm 0 77452 instead

sm 0 11916 .. nok .. should be sm 0 77452 instead

sm 0 11916 .. nok .. should be sm 0 77452 instead

5 write attempts failed. Exiting ...

---

Another issue is that i have one cable that actually is 3 cables, i guess that instead of one 3phase cable someone desided that it was easyer to use 3 cables.

here i would like to use one clamp for one of 3 cables on one phase, so instead of multiplying by 690 i would like to multiply by 3*690....

And yes, one clamp for all 3 cables on one phase is not possible because one cable is 250A.

/Peter

The second parameter in the sm command, which is directly proportional to the configured amps and volts, should be kept below 65k. What you're experiencing is an overflow condition on this parameter: 77452-11916=65536. The good news is that the FLM does proper boundary checking on the input parameters, the bad news is that you cannot use 690V with 250A. But you can still post-process your data to get correct readings.

I'm glad that FLM does proper boundarychecking.

What you are saying is that i'm forced to buy 3 clamps for each measurepoint to get the correct values in the database?!

/Peter

Either that, or you extract the data from api.flukso.net and multiply each reading by 3.

Cant you use a one 3phase kwh meter with so pulse, like this http://kwhmeter.biedmeer.nl/Webwinkel-Product-21635783/3-fase-kWh-meter-...

So pulse is more acurate, isn't it Bart?

I will go for 3 clamps.

An API solution will be mor costly in the longrun.

A solution with another box inbetween, alltough more accurate, will also be more expensive specially in the 250-500 amps range.