How to build a WE500-based bellset?

[twocvbloke]

Well, it was meant to be "How to build a WE500 based Subset", but due to a failed ebay bidding program, I didn't get the (2)500 open-type Network to go with the bells, which I'm rather annoyed about...

But anyway, the other day I won these bells:

http://www.ebay.co.uk/itm/150741580697

A later type than the C4A's fitted to my two WE500s I'm guessing, as the coil looks different and the wires are not cloth covered, but that aside, how would I go about turning those into a bellset? 

I have a BT Bell 50E bellset which is just wired across the "A" and "Bell" wires, but as the WE500 bells are a bit different to what are essentially GPO bells, there's 4 wires to work with, and I'm not entirely sure about whether I can wire them as per BT specs or if I should add a capacitor or something to make them work properly... 

Even though I'm sure you all know what they look like, here's a pic of the bells (with the seller's ebay ID, seeing how the picture belongs to them):

[dsk]

The traditional ringer had (has) 2 coils, this one has the 2 windings on the same core. If we try to follow the current from Tip (a) to Ring (b) the current will flow in to Black through a 1000 ohms winding and out on Slate.
The next winding starts with Slate/Red and goes through a 2650 ohms winding.  (The reason for different windings has some link to party line configurations ) 

Where to put the capacitor?  The Western Electric way is to put it between the windings (Between slate and Slate/Red) The European way is to put it in one of the ends.

For UK wiring, the capacitor is located in the master socket.  The capacitor in the master socket is approx 2µF and will be enough for several phones. In the US each ringer has a capacitor of approx 1/2µF.

dsk

[twocvbloke]

That's the thing, my two WE500s (and the motorola cordless) run on the A and B wires, so no requirement for the Bell wire, the only phone that is running with the A, B and Bell wires is the BT Viscount. And, more confusingly, the Master socket has an ADSL filter faceplate fitted, so it's basically two masters in one, and a 2-wire phone will happily work from the ADSL modem socket (with the modem unplugged of course), so the Master socket capacitor requirement is just not there any more, it's a left-over from the post-GPO days, made to counteract the bell tinkle effect, which the WEs don't suffer...

Hence why I was after the Network that was on ebay that I could have just wired up to act like a phone that was permanently on-hook, and of course, if need be, put it to use later as a subset for another phone, just connect it all up and plug it in, that way the network block would have done all the stuff that it does to make that nice Western Electric 500 set of bells ring...

I'll have to admit, electronics aren't my strong point, I can unsolder and replace like-for-like components, and test some types with my multimeter, but I'll be damned if I knew what they did 90% of the time...

[dsk]

Then, I just would have been as it is, The network from a 500/2500 is not easy to use as a subset, it can be done, but it may be some more complicated.
Start with making your ringer box, connect the ringer and a capacitor of (~)0.47 µF rated at 200V or more in series with the ringer. If you put it between Slate and Red/Slate or in one of the ends of the ringer doesent matter.  Leave a little room in the box for a network, you may need it later.
If you happens to come over a telephone from whom you may use the transformer (/induction coil) you may probably use it.

Good luck
dsk

[dsk]

Like this?
dsk

[twocvbloke]

That looks easy enough, and I have a 0.47µF capacitor here, pulled out of my vacuum cleaner spares box (they use them for spark quenching on 220-240v vacuum cleaner motors), all I need now is a box to fit the bells in and I'll be set...

As for the subset idea, I was randomly thinking of merging GPO technology with Bell System technology, in the form of a GPO 713 pendant phone hooked up to a WE500-based Subset rather than a proper GPO Bell 50B or 50D (which have the guts of a 706/746 in them, and either 1K bells or 4K bells, depending on the B or D version), just because it's fun to be different...

[twocvbloke]

Darn, I thought it was a 0.47µF, but it appears to be a 0.047µF, I think, it's got ".047K275V~X2" along the top....

Ah well, they're cheap enough to buy...

[dsk]

0.47µF almost 1/2µF should be fine.

dsk

[twocvbloke]

Does that mean the one I have is a 0.47µF then?

[LarryInMichigan]

I don't know what kind of capacitors are used in vacuum cleaners, but both .47µF and .047µF are common values.  Do not use electrolytic capacitors as they are polarity dependent.

Larry

[twocvbloke]

This is the capacitor in question, I started putting it into a GPO terminal block when I noticed the rating...

And yeah, it's meant to be placed across the motor's wires in a vacuum (or any brushed motor), this one I think was meant for a power nozzle motor, so it's a tiddler compared to the others I have replaced in the past...

[LarryInMichigan]

If that capacitor connects in parallel with the motor, it would not be .47µF, or it would blow your fuse.

Larry

[twocvbloke]

I just remembered where it came from, it was a fluorescent light fitting that wasn't working right until I pulled that cap out, I thought it seemed a bit small for a motor...

Not sure why I kept it though, must have been a reason that has long since escaped me...

Anyway, I'll go look for my other spare capacitors to see if there's anything else that could be used...

[dsk]

This page tells a little about reading capacitors: http://tinyurl.com/7jd25q
On the other hand If it is a 0.047µF The ringer will not ring, and that's it. Just try.

dsk

[twocvbloke]

Yeah, that's why I fail at electronics, the component values are never easy to work out for someone like me...

Anyway, I found two capacitors that are of the right type, but the values, erm, yeah...

One is this:

330n K 275~ X2

the other:

100n K 400V36BL

I know I bought them for a reason, but I can't remember what for, and I probably asked for them in Micro Farad ratings, but I can't recall what they were, I'm guessing the top one is 3.3µF, and the bottom one 0.1µF, maybe....

Can't try anything out at the moment, cos the bells aren't here yet, so still have to wait for those to arrive, though, thinking about it, I do have a spare Master socket somewhere that I could probably cannibalise for a capacitor...