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Re: 3-phase reactor



Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>

Hi,

Any small inductance meter driven by say a 9V battery will not be able to pump enough current through a big iron core to get past the hysteresis curves.

http://www.lassp.cornell.edu/sethna/hysteresis/WhatIsHysteresis.html

It's like trying to push a bus with a feather. So the reading will be very high until you get enough current to get the iron working.

Typically you need to get out a variac, loads, scopes and such to measure it the direct basic way. There are some high current AC meters out there, but they are usually "special". Everyone really just sets it up on the bench with scopes and all...

Once you get a known AC current though the winding, you can measure the voltage across the winding and the inductance is:

L = V / (I x 2 x pi x 60)

You can even measure the inductance for various currents and make a graph of when the core kicks in (low current) and when it saturates (high current).

3 phase is a bit odd since they use the other phases to "fight" each other and keep core magnetization down avoiding early saturation. Just one phase will probably saturate sooner than expected if I am thinking right on that.

Of course, in your case, you are lucky and it is already labeled ;-))

Cheers,

        Terry


At 10:03 PM 7/11/2006, you wrote:
Hi All,

I recently came across a reactor in a junk bin with three separate coils wound on the same core. It is marked:

 AC253V 24A 0.15mH 3ph.

When checking it with my AADE LCII meter, each section measures 1.50 mH. - ten times the rated value. I was hoping to use this as a ballast but I have no idea what value to expect. Any reactor guru want to take a shot at enlightenment.

Matt D.