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Re: 3-phase reactor



Original poster: "Sean Taylor" <sstaylor@xxxxxxxxx>

I've never seen one with all 3 coils on the crosspiece.  They are
frequently contructed with the same type of core that you're
describing, but with one of each of the phases on each of the legs.
For a picture, see this eBay auction:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=170005487803

Because of the 120 degree phase difference on each phase, the currents
end up cancelling through the side legs (not completely cancelling,
but interacting).  Is the center leg of the figure eight twice the
size of the rest of the legs of the core?  If so, that sounds like a
typical EI core for single phase use.  Is it possible this inductor
came out of something with 2 more?

Sean


On 7/12/06, Tesla list <tesla@xxxxxxxxxx> wrote:
Original poster: Mddeming@xxxxxxx

In a message dated 7/12/06 2:13:50 P.M. Eastern Daylight Time,
tesla@xxxxxxxxxx writes:
Original poster: "Sean Taylor" <sstaylor@xxxxxxxxx>

I definitely wouldn't trust the L meter, the iron core will mess
things up for the meter since it doesn't have the current to actually
"magnetize" the core.

Anyway, the voltage, current and inductance all make sense - if one
assumes that the voltage is phase-phase (typical), the current is line
current (again, typical), and the inductance is in series with no
common connection (again, typical).

Now, is the core 3 seperate cores, or is it 1 core with 2 windows?  If
it's 3 seperate cores, it would be easy to use with single phase,
simply parallelling the different windings for the appropriate/desired
current.  If it's one common core, parallelling any 2 windings won't
do much for you since you'll either be making a common mode choke (and
won't limit current much) or just increasing the effective number of
turns, limiting the current further (by a factor of 4!).

Sean Taylor
Urbana, IL

Hi Sean,

The core is shaped like a rectangular figure-8 with all three coils
on the central cross-piece. I'll be using Terry's suggestion of
measuring V & I with a scope and see what happens.

Matt D.