Jacarta intelliAmp - Would L & N not cancel each other out?

[ban-all-sheds]

I am puzzled why it states this:

View attachment 127560

and then this:

View attachment 127561

What's puzzling about that?

 

[EFLImpudence]

That it apparently does not work with cables of other ratings?

 

[JohnW2]

But the cores do not lie in a plane.

Assuming they are straight over the relevant length of cable, The L and N conductors surely define a plane (in which they lie), don't they?

Kind Regards, John

 

[ban-all-sheds]

That it apparently does not work with cables of other ratings?

Consider its target market.

 

[ban-all-sheds]

Assuming they are straight over the relevant length of cable, The L and N conductors surely define a plane (in which they lie), don't they?

Maybe in theoretical topology?

Other than that, can you really have a twisted plane?

 

[Edddd]

Maybe in theoretical topology?

Other than that, can you really have a twisted plane?

No. You could define a plane that's tangential to the actual ribbon/helix-like surface at a given position on the cable. But it's just an approximation to illustrate why you can measure a magnetic field outside the cable. I think the limitations of that approximation are one reason why devices using the principle are not widespread.

 

[ban-all-sheds]

No. You could define a plane that's tangential to the actual ribbon/helix-like surface at a given position on the cable.

But only relative to one of the conductors, surely?

 

[Jackrae]

Electric snake oil ?

 

[ban-all-sheds]

I doubt it.

I'm sure it must work at least reasonably well.

 

[roasty]

Jakarta make a load of datacentre monitoring hardware (humidity, temperature etc..) they are well respected, I've used their stuff, it's good and reliable.
I suspect therefore, that these would work rwell, I'd imagine they are designed to monitor current draw to server racks but without the necessity to power anything down. They'll probably also be reassuringly expensive (I reckon a couple of hundred quid each) for that reason I think the likelihood of them having multiple hall sensors and a bit of logic to do the calculations is probably how they work. Looks like an interesting product

 

[333rocky333]

Theres been clampmeters that you can put round a cable for years, there was even a post on here about them

http://uk.rs-online.com/web/p/clampmeters/4954399/

https://www.diynot.com/diy/threads/clamp-meters.123644/#post-825720

 

[JohnW2]

Maybe in theoretical topology? Other than that, can you really have a twisted plane?

I suspect the definition might be a stumbling block, but I imagine that Mr Einstein might have had some thoughts of the matter!

To be honest, on reflection my mind was probably thinking about flat T+E. However, it's got me thinking about something I probably have never considered - do all 'round' multicore cables have their cores 'twisted'?

Kind Regards, John

 

[rsgaz]

do all 'round' multicore cables have their cores 'twisted'?

I would say yes. It will even out stresses in the wires when it is wound onto a drum, rather than a single wire taking the 'long route'.
Also, keeps them together neatly for going through the sheath extruder, rather than individual wires flopping around.

edit: even with large segmented cables...

 

[Edddd]

It also helps reduce the amount of interference picked up or emitted!

I think the factor to consider in this context is the distance from the cores to any hall sensor versus the twist length in the cable. If it is small then the cores-in-a-plane approximation works better. So you might not get very good results with CAT5.

 

[Jackrae]

On the basis that it works, I'd surmise that the device is picking up the predominant flux 'leakage' from the conductor nearest to the actual sensor, ie that on the outside diameter of the cable. The only place where the flux truly cancels out, in a multicore bi-directional cable (flow and return), is probably the points at which both live and neutral surfaces are immediately adjacent or in contact, ie the central core of the cable. I note the literature suggests that the sensor position requires "optimising" "The intelliAmp’s unique optimisation system helps to ensure that the sensor is ideally positioned to obtain accurate readings"