Hi there, Dave.

Can you run the solenoid from DC?  In that case, the inductance=20
mostly drops out of the equation and you are left with the resistance=20
controlling the current.

That means that you will need less DC voltage to achieve the same=20
flux level.  You'll have to experiment with it but I'm making a WAG=20
that about somewhere between 25% to 50% of the original AC voltage=20
will work just fine.

FWIW - I regularly operate pneumatic solenoid valves rated at 120 Vac=20
from about 33 Vdc (24 Vac rectified & filtered).  Some of these have=20
been working reliably for more than 30 years.  Temperature rise was=20
virtually indistinguishable compared to running from 120 Vac.  These=20
are relatively-small valves (1/4" NPT direct-acting valves).

My thought that a simple DC-DC up-converter is MUCH simpler than=20
rewinding the coil.

dwayne


At 02:13 PM 4/21/2015, David VanHorn wrote:
>Some things seem to get harder to find as time goes on.  Things like this
>used to be done all the time, probably from paper nomographs that never go=
t
>enwebified.
>
>
>I have a solenoid coil that I'd like to re-wind from 120V to 12V.
>The complication is that I need to keep the amp-turns and the inductance t=
o
>similar values.
>
>The original is 70 ohms, 19 layers of 176 turns or 3344 turns.  I wasn't
>able to measure the inductance due to high series resistance.
>
>Seems like this should be possible, and yet I've found precious little in
>data on how to rewind for different voltages.
>
>I tried re-winding for amp-turns and had limited success, but the output
>energy was very limited.
>
>The device in question is a BD-10AS from ElectroTechnic products.
>The magnetic field of the solenoid opens a switch which is integral to the
>function, and so I need about the same level of flux.  I am theorizing tha=
t
>the reason for low output was the lower inductance of my 400 turns of #19
>vs
>
>I need to use it far from an outlet, and powering it with an inverter is
>almost certainly going to result in a smoked inverter. I thought of a
>series pack but the idea of a battery at 120V with any real output current
>is pretty scary.


--=20
Dwayne Reid   <dwayner@planet.eon.net>
Trinity Electronics Systems Ltd    Edmonton, AB, CANADA
(780) 489-3199 voice          (780) 487-6397 fax
www.trinity-electronics.com
Custom Electronics Design and Manufacturing

--=20
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