wireing your own inductors

[marty]

Hi All;
Can the coils in an old phone be done by a regular person.. I have lots of wire about 28-34 gauge wire, and would like to know if it is possibel to make an inductor for an old phone if you don't have one ? I would need I guess is how many feet to an Ohm and then what ohmage each coil is... I am thinking of a home made subsystem... Since I have only one subsystem and more than one phone...
THANK YOU Marty

[dsk]

It is quite much mechanical to come up with. A gear to make it possible to crank about 20 rev. pr second. A moving coil, or magnet etc.etc.

The resistance use to be about 25 to 45 ohms. The no of turns should be enough to generate a no load voltage of 90-100V at 20 Hz.  (usually you don't crank that fast)

I don't think you may give it to many turns whit-in 45 ohms. (The generator may big huge)

Not my intention to kill your idea, but it needs a lot of planning.

If you are rewinding a generator, just fill it up with turns.....

Good luck

dsk

[marty]

Hi All;
Dsk, I am thinking of the Subset Inductor, and Not the Generator..
But, THANK YOU for Your Input..
THANK YOU Marty

[Phonesrfun]

I am no engineer, but I seem to remember from way back that the composition and configuration of the iron core has much to do with the properties of an inductor.

Old phones that had the tubular inductors used iron wires bundled together to make the core.  Newer coils use interleaved "E" and "I" shaped iron strips that are piled up to make the core.  Sometimes the strips are made to be in contact with each other, and sometimes not, based on the results desired.  101A coils that are in the 302 use a special resistance wire in the antisidetone winding that creates the antisidetone cancelling effect.

Bottom line is that a basic inductor can most definitely be made, but pay attention to the direction of the coil windings, the ratio of the number of turns, and the guage of the wire used in the primary and the secondary windings.

I have no clue as to how to direct you in any of those facets.  Much has been written over years and years on the subject, and the mathemetics of the topic can be kind of numbing.

One person I know is probably equipped to help you out, but he doesn't hang around this forum, although I have tried and tried to get him here.  He is a delightful guy named Colin Chambers and his website is http://oldphoneguy.com/  ( dead link 03-18-22 ) 
He knows a lot about old phone circuitry and the basics that make up the components.  If you wish, I can provide you with his phone number.

[dsk]

Hi All;
Dsk, I am thinking of the Subset Inductor, and Not the Generator..
But, THANK YOU for Your Input..
THANK YOU Marty

Thank you for turning me to look in the right direction.

Yes you can!

The very first induction coils were made on a bundle of glowed iron wire. A finger thick bundle wide a wooden square in each end. You may make them on a core of the type of wire used for setting up flowers in the flower shop.

An old description I read was for making a local battery telephone. Primary 200 turns (as low ohm as possible) and 1800 turns at the secondary. I made one when I was about 12, and yes it worked reasonably well.

The winding ratios in more modern telephones are made to match the impedance of the different parts, transmitter, receiver and line (600 ohms at 800-1000 Hz)

This is some more info: http://tinyurl.com/6cjzdtn     and   http://tinyurl.com/68jybay   

The next now will be to identify a transformer or coil you want to copy.

The result will probably be some different, but the values are usually not very critical.

dsk

[marty]

Hi All;
DSK, Thank You, It looks like there is a wealth of information there... Just what I need...
THANK YOU Marty