How Does It Work?

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Re: How Does It Work?

It always amazes me how technology moving forward presents us with these new "gadgets". I have used my clamp-on around all conductors before, but I do not think with the same results this unit will provide. I think that a email to Megger is in order.
 
Re: How Does It Work?

Unlike conventional clamp meters, the MMC850 has a complex
array of Planer magnetic sensor coils to calculate the
current flowing in the conductors of multicore cables with
either 2 or 3 cores, and in either flat or round section cable,
up to 100 A. The convenience and potential time saving
from using the multi-core clamp is considerable.

It's right there in the spec sheet-

http://www.megger.com/common/documents/MMC850_DS_en_V02.pdf?ref=/us/products/ProductDetails.php?ID=656

-Hal

[ December 18, 2005, 06:46 PM: Message edited by: hbiss ]
 
Re: How Does It Work?

I don't know, but FLUKE has had one out for about 5 years or so.
They work well where you can not get all of the way around the wire.
 
Re: How Does It Work?

I don't know exactly how it works, but I'll take a guess. Since the conductors in a cable have some small amount of space between them, the magnetic fields created by the two currents don't completely cancel each other out. The current from one wire will predominate on one side of the cable, and the current from the other will predominate on the other side of the cable. The difference will be strongest very close to the cable (i.e. some fraction of the space between the two wires), but almost unmeasurable at some multiple of the cable spacing.

So the basic idea is this: place about 4 current sensing coils around a cable (and very close to the cable), and you should be able to use the differences in readings from each coil to determine the total current flowing.

You need 4 coils because you don't know how someone will orient the meter with regard to how the wires are oriented.

It seems like you might have to tell the meter what type of cable you are measuring for it to do the calculation.

Steve
 
Re: How Does It Work?

To Steve's guess I will add my own. The word "planer" (pronounced "plain ? er") tells me that they have at least one coil in each of three planes. That is, there would be one sensor oriented like the flat surface of your desk, a second oriented like the flat surface of a book that you stand on its end on the desk, and a third oriented like another book that is perpendicular to the second surface. With the ability to separately detect and measure magnetic fields in three planes, you can more accurately distinguish among any sources of magnetic fields (i.e., any current-carrying wires that are surrounded by the sensors).
 
Re: How Does It Work?

Originally posted by rattus: I will only add that "planar" is misspelled.
Click to expand...
No it's not.
planar [MATH] Lying in or pertaining to a euclidean plane.
Click to expand...
From the McGraw-Hill Dictionary of Scientific and Technical Terms, 5th Edition, copyright 1994.
 
Re: How Does It Work?

C. B.,

Check the earlier posts. It is spelled "planer" which is a woodworking or metalworking tool. Spell check would not find this error.

Do you suppose the Chinese have a spell check program?
 
Re: How Does It Work?

I guess it's a good thing that I am getting new glasses on Wednesday. I can't tell an "e" from an "a." I guess I'll have to leen on you for spelling assistance. :D :D
 
Re: How Does It Work?

I caught the spelling error too, (Error A) and couldn't believe Charlie argued with Rattus about it. :D

I agree with both Steve and Charlie and thought Charlie's hypothesis was probably pretty darn close to what it does.

And I also want one!
 
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