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-   -   Vintage French Doorbell - Surely not 220V AC working!!! (https://www.vintage-radio.net/forum/showthread.php?t=150416)

rodcrux 12th Oct 2018 12:27 pm

Vintage French Doorbell - Surely not 220V AC working!!!
 
3 Attachment(s)
My nearly son-in-law and daughter bought an old house and he wants to keep as many of the original features as possible.

He has achieved that in most respects - except for the old doorbell (pictures attached).

Despite his best efforts - and a visit from an "electrical engineer", it remains in a non-working state. Of course I opened my big mouth and said "It's only a simple ****** doorbell - any fool could get that to work!"

So this fool now has it here - and despite this particular fool's best efforts it refuses to work.

Clearly marked 500 OHMS on each of the two coils.
(Yes, there is continuity between the terminals at 1000 OHMS resistance)

I have tried an AC transformer rated at 15.6v 0.2 amp - which gives no more than an initial "ping".

Do I need a higher voltage transformer?

As a matter of caution- I saw one of these bells in auction described "Door bell 220 volt Albert Pernet - Paris"

Really? 220 volt ? :o

russell_w_b 12th Oct 2018 1:06 pm

Re: Vintage French Doorbell - Surely not 220V AC working!!!
 
Quote:

Clearly marked 500 OHMS on each of the two coils.
(Yes, there is continuity between the terminals at 1000 OHMS resistance)
Looks suspiciously like the spec of a type 59A telephone bell to me with polarised armature. Have you a telephone magneto you could try it on? Or a 25 - 75V a.c. supply at a frequency of either 16 2/3 Hz or 25Hz?

terrykc 12th Oct 2018 2:34 pm

Re: Vintage French Doorbell - Surely not 220V AC working!!!
 
Yes, my thoughts as well. As far as can be seen from the pictures, there is no interrupter, so there is no way that it could work on DC

Skywave 12th Oct 2018 2:45 pm

Re: Vintage French Doorbell - Surely not 220V AC working!!!
 
Quote:

Originally Posted by rodcrux (Post 1082507)
Clearly marked 500 OHMS on each of the two coils.
(Yes, there is continuity between the terminals at 1000 OHMS resistance)

As a matter of caution- I saw one of these bells in auction described "Door bell 220 volt Albert Pernet - Paris"

Really? 220 volt ? :o

Well, let's do a bit of arithmetic.
On the assumption that the impedance of those coils will be almost resistive - i.e. 1000 Ω, then when connected to 220-v.a.c., the current will be 220 รท 1000 = 220 mA. The power will be 220 x 0.22 (watts) = 48 watts (approx.). I do realise that that power - mainly as heat - will be dissipated for a very short time, but still seems excessively high to me. Perhaps the reactance of the coils is not negligible, especially if it is intended to be used with a supply freq. less that 50 Hz?

Al.

Nickthedentist 12th Oct 2018 3:00 pm

Re: Vintage French Doorbell - Surely not 220V AC working!!!
 
Yes, it's a telephone bell, and will still work as such!

Nick.

Guest 12th Oct 2018 3:49 pm

Re: Vintage French Doorbell - Surely not 220V AC working!!!
 
Quote:

n the assumption that the impedance of those coils will be almost resistive
Hardly likely, lets take 16Hz (normal bell ringing) at 50V AC or so, so 220V at 50Hz 'ain't a lot more (4X volts nearly 4X frequency) current. Yes it will work and not blow up on 50Hz 220V.

rodcrux 12th Oct 2018 4:27 pm

Re: Vintage French Doorbell - Surely not 220V AC working!!!
 
Sadly, no, I don't have such a magneto.

russell_w_b 12th Oct 2018 4:28 pm

Re: Vintage French Doorbell - Surely not 220V AC working!!!
 
The 'carrier fail' bells on the old ST&C HF transmitters at the long-demolished BBC Skelton 'B' (OSE9) station had movements similar to this wooden-based French one, and to telephone bells, although they worked on 50Hz and at about 50V as I recall, perhaps incorrectly. But they were a polarised movement and were quite sensitive.

Incidentally, a 59A bell movement with a d.c. resistance of 1000 Ohms (both bobbins in series) has an impedance of typically 1712 + j2022, or a Z of 2649 Ohms at 25Hz and 2502 + j3941 or a Z of 4668 Ohms at 50Hz; this particular bell movement being that of a Type 'F' field-telephone. So a bit of 230V mains won't harm yours, drawing - if the characteristics are similar - about 50mA. But make sure your bell-push is mains-rated!

rodcrux 12th Oct 2018 4:33 pm

Re: Vintage French Doorbell - Surely not 220V AC working!!!
 
Thanks but even I would not consider connecting a mains supply to those exposed screw terminals!

I think I need to get hold of a suitable transformer with an output in the range of 50V - 100V AC and try that.

barrymagrec 12th Oct 2018 4:48 pm

Re: Vintage French Doorbell - Surely not 220V AC working!!!
 
I think I`d be inclined to use a relay with a low voltage supply on the bell push side if this bell is running off the mains.

russell_w_b 12th Oct 2018 5:17 pm

Re: Vintage French Doorbell - Surely not 220V AC working!!!
 
Or you could put a mains - to - 6V transformer primary in series with the bell (terminals beyond reach, of course), and run the secondary winding to the bell push, so when you press the button it shorts out the 6V supply, loading the transformer primary sufficiently to let enough current through to ring the bell

Guest 12th Oct 2018 5:20 pm

Re: Vintage French Doorbell - Surely not 220V AC working!!!
 
Quote:

so when you press the button it shorts out the 6V supply
I did that for a "knife switch"ed light, the transformer went short because I didn't put a snubber in circuit.

TonyDuell 12th Oct 2018 5:39 pm

Re: Vintage French Doorbell - Surely not 220V AC working!!!
 
UK telephone bells (the old 1k resistance ones) will ring, albeit not too well, from a 30V transformer, it was suggested that you connect a 8uF (or 10uF) non-polarised capacitor in series with the bell. I tried it many years ago, it did work, although you had to adjust the positions of the gongs for the best ring.

Ah, I've found where I got that idea from. It was the Practical Wireless home telephone exchange project in the Feb 1975 issue.

This bell looks very similar to a telephone bell, so you might try that. Or try a telephone ringing supply if you have one.

Crazy idea, but it is French.... Was it used with a conventional bell push? I could imagine a magneto generator (similar to those in local battery telephones) operated by a lever or crank next to the front door.

Reelman 12th Oct 2018 6:23 pm

Re: Vintage French Doorbell - Surely not 220V AC working!!!
 
Could it be an external telephone bell rather than a door bell? Can you check where the wires go that originally connected to it?
Peter

OscarFoxtrot 12th Oct 2018 7:49 pm

Re: Vintage French Doorbell - Surely not 220V AC working!!!
 
I think it is a telephone bell, and IME will probably ring down to about 10 volts, but the 50Hz will be the killer. The electro-mechanical resonant frequency won't.

An electronic ringing generator such as this one (Ebay; no connection with the seller) is probably the easiest way to get it working again. A capacitor and ~ 3k3 resistor in series.

broadgage 12th Oct 2018 10:45 pm

Re: Vintage French Doorbell - Surely not 220V AC working!!!
 
I suspect that this is for 220 volt AC supply, with a DC resistance of 1,000 ohms, a total AC impedance of about 2,200 ohms seems reasonable.
That would mean an input current of about 100ma, and a resistive dissipation of some watts, which would be fine for short term use.

Alternatively it might be for 127 volt mains, of which there was once a lot in France.

Possibly for some industrial or railway use rather than a domestic door bell.

Graham G3ZVT 13th Oct 2018 1:13 am

Re: Vintage French Doorbell - Surely not 220V AC working!!!
 
1 Attachment(s)
That's much more likely to be a telephone bell.
The GPO equivalent is arguably this

Attachment 170803
which was a "feature" covered in paint, when we moved into this house. I retained it for the same reason as your son-in-law, but now you and he knows what it is perhaps he will want to use it for it's original purpose?

It would have been a brave person who would have connected a foreign bell to the telephone network pre-deregulation, the genuine article would have been subject to a monthly rental.

Start another thread in the Telecoms section if you want more information, and how to connect it.

<EDIT> here's a pair of them in another auction, correctly described.
https://www.the-saleroom.com/en-gb/a...7-a5bd010b20fa

terrykc 13th Oct 2018 10:30 am

Re: Vintage French Doorbell - Surely not 220V AC working!!!
 
Quote:

Originally Posted by rambo1152 (Post 1082710)
It would have been a brave person who would have connected a foreign bell to the telephone network pre-deregulation

Not foreign bells but thee were a lot of bells - complete with phones - that were connected to the UK network in the 60s! I was surprised by the number of homes I visited where I heard the tell-tale bell tinkle as someone dialled out on the upstairs extension!

So, a two wire connection with both bells in parallel instead of series and no bell tinkle suppression!

I must admit, though, that in the mid 70s, when I once tried to phone my wife one evening to warn her that I would be late (no trains) and didn't get an answer it was because she'd been bathing our baby daughter in the bathroom towards the rear of the house and hadn't heard the phone.

As a result, she demanded an extension bell in the kitchen. I agreed - on condition that it came complete with a dial and handset! I had a wall mounted phone I'd acquired which fitted neatly above the kitchen worktop - but I made sure that this was wired correctly withe bells in series and, of course, bell tinkle suppression!

rodcrux 13th Oct 2018 11:58 am

Re: Vintage French Doorbell - Surely not 220V AC working!!!
 
Graham

THANK YOU! for what is certainly the definitive answer to the puzzle.

Of course, . . . . . it is a telephone bell and NOT a doorbell!
I can see how the misunderstanding arose.

When he first discovered the bell it was high up on the hall wall near the front door - without any existing wiring - and assumed, not unreasonably, that it was a doorbell.

Many thanks to all who have contributed to this thread - I'm in awe of the depth of knowledge and scope of experience which are freely shared in here!

OscarFoxtrot

Thank you for the helpful information - I took a look at the ringing generator device on eBay - it looks just what is needed.


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