ECN Forum Forums Technical Discussion Electrical Theory and Applications Power Quality / Inductors-R-us!

Paul:
Here are the results of my un-scientific scientific test, test conditions 250 foot roll of 12-2 using only the black conductor and a short piece of white to complete the circuit.
The load purely resistive 9.9 amps @120 volts.
Empirical data: no physical signs of heating not that my hand could detect.
Voltage drop was 8 volts this was an improvement from yesterdays test.
Now heres the part you have been waiting for, Out of range, on the gauss meter at 18 inches and down to 159 at 1 meter. These readings were taken on top of the coil on the side of the and from underneath the workbench a spherical cube if you will the reading were the same.
The voltage drop difference because I was using half the wire as yesterday but the magnitude of the gauss reading is not inconsistant with what I have been reading from the manual from the ' Magnetic Sciences International', this is what they claim for readings of Knob and Tube wiring that is seperated by the width of 2 two by fours, or joists. In fact from 6 meters away I was reading 6mg, which I thought was incredible, since they claim 0.0-0.3 to be the ambient Normal range. Outside near the power lines in the street I was only getting 1.7mg.
Conclusion ???
Hey I only did the tests, best guess is these people from the EMF and Mag. Sciences are definitely on to something.
I originally bought the gauss meter from Mike Holts Newsletter, and have learned alot about how just a shorted neutral can cause a Net current on the water line and a disturbing magnetic effect. Its really quite interesting.
So what do you think , Paul ?

Electric Eagle:
When I plugged in that whole roll of wire I was really surprised how fast it heated up, but when thought about the overall length is 500 feet but surprisingly too was it only dropped 10 volts at a 10 amp load.
Can imagine your surprise when seeing the 'Hole-Hog' barely limping along wiht 400 feet of extension cord. I would have been quite P*****.

-Mark-

Mark,
I was a little ticked off, mainly because it was an almost new Hole Hawg, but the guy was new and inexperienced. I just explained what was happening and made it clear to not just ingore it when something doesn't seem right, fix the problem.

[This message has been edited by Electric Eagle (edited 05-22-2002).]

Motor-T,
I wonder what the Gauss meter would show with no load/current.My educated guess would be that the reading would be very small.
This would support that these non-contact detectors are electric field detectors and don't rely on the presence of a magnetic field(current flow) for voltage detection.
Chris

Motor-T, you da man!

*explosions and shouts of "Eureka" imminate from motor-T's garage...*

I'd certainly expect a reasonable magnetic field with just the one conductor in use from the coil of cable.

How about a third stage to the experiment? What I have in mind is using both conductors but arranged so that the currents are flowing the same direction (e.g. load connected between the black from one end and the white from the other, power on to the remaining two opposite ends).

That way we'd have the same resistance as in the original experiment, and the same heating effect from I^2*R in the coil. With an effective 500' coiled up, you should see an increase in the magnetic field strength.

Paul:
Why not, ' i'll have a go at it', I'll let you know what happens.

-Mark-

Et al:
Ok I had my go at it, this test was the third of an infinite series of un-scientific-scientific test.
The roll of 12-2 was set up such that the current was all in the same direction. as usual the 10 amp load. 120 volts.
Results:
This is unbelievable, the coil was vibrating, I kid you not,(little Jack Paar lingo), The bench was vibrating, the Gaussmeter went bazerk. It was reading 17.5mg from at 6 meters, the voltage drop was 13 volts or 107 at the terminals.
I think for my next test i will get 250 volt incandescents and try 250 volt source.
Now when I say the coil was vibrating Not so much visual but you could feel it with the hand and the bench too, should get great results with 250 volts. Eh ?

-Mark-

Motor-T,

Wood bench or metal bench ?

Wow...

*...on edge of seat...*

Wow is right, Virgil! Some experimentalists that would make Edison and Tesla proud!!

As to whether getting rid of the long extension cord took care of the problem, I haven't heard back that it didn't. I even called the client and left a voicemail message--"Everything going all right?", and haven't heard back.

No news is good news...

Cliff