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Converting magneto/local battery to common battery

Started by scottfannin, May 19, 2020, 02:03:23 AM

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scottfannin

Continuing this in a separate thread.  Article http://www.classicrotaryphones.com/forum/index.php?topic=23802.msg237683#msg237683 was about inductors but it evolved into how to make a magneto/local battery device into a common battery one that can connect to a modern phone line.  For wooden wall phones and for early wooden subsets.  You can catch up on page 2 or so of that.  Where last we left it, we were making circuits for changing a wooden wall phone to work on a common battery system.  I have attached the most recent incarnation of a diagram for this as a carry over from the original diverged topic.  I'm pretty good with Visio so we can pretty readily convert what people share into documented versions and then send them back out, which is what we were doing. 

Being forced to hide, my relatively new telephone skills are advancing more quickly before.  I live in New Jersey just across from the New York border.  I only leave my house every 3 weeks to exercise the car and buy food because people I actually know are ill and a few people's relatives actually died.  Fun fact, my town has a large monument to the 1918-1919 flu epidemic, which was really bad here too.  So I have some time to study these things now.  And a kid to amuse, he hasn't left the house in something like 7 or 8 weeks now.  He's become able to tell a Stromberg-Carlson from a Western Electric just by looking and can guess the age of a WE 317 just by looking and he assembled a WE 500 from scratch using just the wiring diagram from TCI, not bad for 11 but when you're kind of in a nice cage for days on end you can learn stuff like that. 

But anyway, today we worked on condensers.  You need them for the modern phone network.  0.47uF for the ringer.  Give or take 2uF for voice if you can work it in.  But if you're lucky sometimes you find a single huge capacitor in the wooden phone.  It can be anything from 1uF to 5uF, often 2uF.  Even if it works perfectly, it will only be one.  Plus my experiments to see what happens if the ringer capacitor is not 0.47uF have shown a limited tolerance for that.  I see people solder wires onto a mylar capacitor and kind of suspend it in the air with no insulation.  It looks awful.  Bad enough you can't "restore" something that was rarely even there, but does it have to look too low-budget for old Doctor Who?  So we get to thinking, what do we have around?  We had stripped and re-stained two badly destroyed wall phones.  So we have some dark walnut Minwax left, from before the local hardware store closed down.  We have water-based polyurethane.  We have big and small size 0.47uF and 2.0uF film capacitors.  We have heat shrink tubing.  Solder.  One of those paddle-shaped drill bits for boring big holes in wood.  Glue.  I found some unexplained wood junk in the crawlspace, probably came with the house but it wasn't pine, there was some grain to it and no knots.  We have a miter saw machine and a drill press.  So...let's make "Amish Condensers"!

1) Chop the wood into various experimental shapes, sometimes making thin slices for potential covers.
2) Hollow them out with overlapping paddle shaped drill bit and drill press.
3) Sand lightly to remove splinters and rough edges.
4) Stain.
5) Coat 2 or 3 times with polyurethane, making sure last one is "matte" for that pseudo-patina look.
6) Select appropriate capacitors (shaped and sized for the block ideally).
7) Place solder blobs on the leads near the component itself.
8) Force small heat shrink tubing over most of the leads, leaving maybe 1/3 inch at end.
9) Shrink it, now the blobs act like holders even though the leads are usually too thin for the shrink tubing.
10) Drill 1/8" holes as appropriate in the wooden blocks.
11) Force the component leads through the holes.
12) If appropriate, put a lid on.  For some, just put the open side against the wall of the phone to protect it.
13) Usually, you can't drill through some side of it because the point of the paddle bit would go through.
14) Drill across that to make a hole for a wood screw or two to fasten it in the phone.
15) Bend the leads over a little so they are inclined to stay.
16) Stuff cardboard into any space left inside the hollowed block.
17) Hook the capacitor leads and some "condenser leads" together and solder.
18) Optionally shrink tube your connections on the outside of the condenser.
19) It's ready to go and looks pretty convincing.
20) I've attached a picture with some of my experiments.

So who knows how to make yourself an inductor?

dsk

Great ideas, and of course you may pretty often use whatever you have of old phone parts.

The induction coil where you only use one winding may be replied of approx any transformer or relay with a high number of turns and a winding with a resistance of 15-100 ohms.

It will of-course often be better if you have a coil from a CB telephone and use it with the circuit equal, or close to equal with the original circuit. 

Regarding ringers, the most of the old ringers (non party-line) will do the job, at least if the magnet is still having a little of its magnetism.  If the total resistance of the coils are less than 600 ohms (Common on older German phones with only 600) you are on the edge of what who is easy to use.  Most ringers works well in series with a 0.47 uF capacitor, but some of the older ones may require a higher value.  It look like weak permanent magnets pretty often are helped by the use of the ringer, so weak ringer may be stronger after some use. 

When it comes to receivers with a flat iron membrane the distance from the magnets could be adjusted by putting in or remove thin rings of paper put between the membrane and the receiver element.  I'm looking forward to see how this project will turn out, it is almost as building a new old phone  :)

I have to admit that when I got a 1920 ish European S.E. telephone with no transmitter and no receiver did I put in elements from a WE 500 that did get in and just packed up with some cotton. That phone worked so well that I was asked if used a modern phone  8) and that's not common for me.

dsk

scottfannin

Today's work on the Kellogg restoration--to be the first complete wooden wall phone I make.  We got a wood wall phone cheaply, American Electric, from Goodwill several months ago, when you could still do that.  It was rusty and full of mud--literally.  I don't know the history of it.  The wood was weirdly solid, but the induction coil was mush.  The bell coils looked like disaster victims.  No winding covers, caked with mud, rusty metal parts.  But what the hell.  I blasted them with WD-40, then de-greased, rinsed, and generally made my wife's laundry sink look like the shower scene in Psycho.  Then quickly hair-dryed.  Amazingly they worked, excitedly and strongly ringing the badly bent clapper.  So in for naval jelly.  Then muslin wrap to make what I think looks nice if not original.  I soldered the hair-like wire between them to patch it after it snapped during muslin wrapping with 0.015 thickness solder.  I glued the wrapped wire to the edges of the cylinders so it would stop unraveling.  Then using two helping hands, I soldered cloth-covered tinsel wire to the fine wires and shrink-tubed it.  Crimped ends on, one with tracers so it looks mysterious to a viewer.  Turned them carefully during re installation in the bracket so that the fine wire between them was held tight and thus not touching the bracket, so I didn't have to put a lame looking muslin square to insulate it.  Pinned the shrink-wrap in the mechanism as I tightened it, so the exposed few mm of the winding wires wouldn't touch the bracket either.  Placed it in the tester with phone line and 0.47 uF ringer capacitor, and it's clean and rings like a puppy wagging its tail.  It's amazing what you can do when you're hiding out from the plague in your basement all day.  Picture attached.

dsk


RB

Nice work!
Tiny wires are Sooo much fun to work with! ;)

scottfannin

So we're almost done.  It works.  We've got a sort of punch list we're working through, like we need to add the door fastener, that cage nut and screw thing.  We need to get acorn nuts to fit the bells.  An easy thing but we will attach the shelf last because obviously that is subject to scratching while working on the rest.  Based on "feedback" (well, to myself and my assistant) we have designed a new Amish condenser.  Soldering tinsel upside-down while it was fastened into the box with bent leads for terminals was a bit tedious and presumably error-prone even though in this case it worked.  I separated stranded 22 gauge wire as recommended in a post somewhere here and then tied the tinsel together with a few knots under a magnifying glass, tinned it, and then soldered it like it was solid wire.  Next time, screw terminals and crimp connectors.  I've attached the new condenser design.  "CEI" is the pretend company my son and his friends operate when playing "technology startup".  No cops and robbers anymore.  "Ghost" is what they call the wooden models of the pretend phone offerings, of course (never mind that it's the only one so far).  Mk. 2 because it's the second iteration.  My point is none of the name info means anything but us goofing around.  The shell will be made out of scrap wood hollowed, drilled, and then once known to be a surviving piece (I shatter about half right now, due to extremely primitive tools), stained and coated with my quick antiquing.  It will get 1 coat gloss oil-based polyurethane and then 2 coats of matte water-based polyurethane--instant old.  Closing the back?  No problem, if you screw it in so that the back faces a wall, there isn't a need for a back and no line where you glued it.

scottfannin

Latest iteration.  Why have a separate P1D ringer to demo the magneto when you can rewire a PTT switch, which would have been an eyesore, to be a DPDT switch to select where the ringer gets its power?

dsk

Yes! and it should be enough with a single pole switching. 
Another solution could be to use a relay, when the generator put out power a relay will change over so the ringe rings on the generator-power, when you stop the cranking, the relay returns to its normal position.   You may test relays, but a coil resistance of at leat 600 ohms, and an operating voltage of 35V AC or more would probably fit.  Relays for lower voltage may be in need of serial resistor/capacitor etc.

dsk

dsk

Related to this project, it could be of interest to read this: http://oldphoneguy.com/local_bat_1.htm
Or just look at what he has published:  http://oldphoneguy.com/

Just remember it is always several solutions, so this is not the one and only answer ... ;)

dsk

scottfannin

It seems like it's a constant struggle to decide what counts as restoring vs. refurbishing vs. recycling and so on.  The thing with using the PTT switch is that it's already there.  No added stuff at all to do it, maybe some rewiring.  But for the single pole switch, I guess just make it so that it either connects an otherwise missing magneto wire or connects the bell circuit to L2, thus making it still impossible to have both circuits operating at once?  That could still work with the PTT with less wires attached, perhaps using only whichever two are most conveniently near the PTT switch already.

scottfannin

The "CEI Ghost Mk 2" condenser.  They came out pretty well, I made three.  The capacitors go in the back with the leads sticking out through holes I managed to keep only 1/16".  Then they're bent to one side and soldered.  The contact screws are cut short enough to miss everything else but left long enough to attach the washer and a future spade connector or two.  It's labor-intensive to make these, but now that they're done, it will be easy to stick them into some box and then run wires to them instead of having to solder upside down in the box.  Not so easy to do at home with no hardware store available.  I put my son to work sorting through a big jar of old washers that a friend placed in the driveway and then walked away from, until he found groups of 4 the right size and matching color.  Had him cut bolts and prepare metal strips too.  I didn't have any good wood so I used a scrap I found in a crawlspace when I moved here and it looks nice when sanded and stained.  No router so I just used a big drill bit and purposely let it go off sideways blowing bits of wood out until I had a sort of slot.  Then to fit the components in, well, someone has smaller hands and better eyes, so I put my assistant to work again.  It's a great chance for him to practice with the multi-meter to check that it has the right capacitance too.

dsk

This thread is so good, because it merges the different experience from many handemen and collectors.  How we solve things depend og tools recources and .... 
Never tought about those capacitors before, but I love the idea.  They seems to be looking great.  I have winded induvtion coils by hand, but have found to use other solutions, and have more spares now than som yrs. ago.  Getting thing working has been my priority, others makes things look like they did when it was new.  If we could combine those skills it could be close to perfect results.  Those wooden blocks with terminals could probably be made to hide other modern parts looking like old.

dsk

scottfannin

I want to get a router so I can make shelves and little boxes.  But I want to try something like that first and with the local lock downs that's just not possible right now.  I have a few wooden phones with the usual smashed off/missing shelves.  It seems possible to make those, not that I ever have but it doesn't seem like a wizard does it.  Those corners though, with all the little fingers of wood interlocked, that I can't figure out how they did.  I looked up "dovetailing" but the pieces are always 2 or 3 cm minimum while the ones on all brands of the real phones are 5 to 7 mm.  So anyway, I finished my first wooden phone with everything in the diagram--but no shelf.  It works.  The magneto turns out to be a Type 48-B.  I suspect that's rare.  There are 4 terminals and two of them generate PDC (Pulsing DC), not really AC or DC, something that surprised me.  Originally, when you pushed the button, it switched to PDC.  That could throw the drop at the central exchange, but did not make bells ring.  So it was much nicer at night or on a party line.  I changed it so that pushing the button and holding it down engages the magneto, but the normal position is to connect to L1 and L2 for bell power.  The two shared terminals connect to 1 bell lead and 1 0.47 uF capacitor lead no matter where the moving parts of the switch go.  The electric parts are as recently discussed.  The induction coil uses only S to SP.  The "condenser" is the "Amish Condenser Mk. 2" which includes 0.47 uF and 2.2 uF capacitors, with screw terminals, and a black tie-down screw.  It has no parts at all that were impossible when it was made.  I used shrink wrapping on terminals, they didn't have that but it just makes sense, they could have put little cloth socks around those if they'd wanted to.  The transmitter is an original, though curiously Stromberg-Carlson and not WE like the rest of the phone arrived as.  The receiver is an actual type 143, not only unaltered but with its original cord, plus working.  I actually kept the knot from the hook, so it is tied back on with a 100+ year old knot.  No wonder my son named these the "Ghost" phones.  It's a little creepy but basically you have to be long dead or we don't want to fix your phone.  The original main phone came from a Goodwill store.  Seriously.  Then some parts from eBay and Amazon, some people on forums, and several dead people's things.  Pictures attached.

Jack Ryan

Quote from: scottfannin on June 09, 2020, 10:07:53 PM
I want to get a router so I can make shelves and little boxes.  But I want to try something like that first and with the local lock downs that's just not possible right now.  I have a few wooden phones with the usual smashed off/missing shelves.  It seems possible to make those, not that I ever have but it doesn't seem like a wizard does it.  Those corners though, with all the little fingers of wood interlocked, that I can't figure out how they did.  I looked up "dovetailing" but the pieces are always 2 or 3 cm minimum while the ones on all brands of the real phones are 5 to 7 mm.  So anyway, I finished my first wooden phone with everything in the diagram--but no shelf.

Phones don't use dovetail joints, they use finger joints. I don't think the shelf uses that either, it uses a form of tongue and groove on the ones I've looked at. The attachment of the shelf to the door uses a butt joint. Perhaps US phones are different.

Jack

dsk

Quote from: scottfannin on June 09, 2020, 10:07:53 PM
The magneto turns out to be a Type 48-B.  I suspect that's rare.  There are 4 terminals and two of them generate PDC (Pulsing DC), not really AC or DC, something that surprised me.  Originally, when you pushed the button, it switched to PDC.  That could throw the drop at the central exchange, but did not make bells ring. 

Right. Here in Norway we used 2 different ways of make our own ringer silent when calling. (grounded ringing was pretty uncommon, and all parties was on the same line in parallel)  Strange with 4 terminals sice one usually is common for the switch and the inductor (Generator)  To get a pretty normal AC you need to crank with a high speed. You may try to rotata as high speed as needed to get 20 Hz    The switch was used to either change between the ringer or the inductor, or the mostly was connected in series, and shorted out the ringer when cranking, and shorted the generator in rest position. (Here in Norway)

 

dsk