Author Topic: Ericsson ringer identification and wiring  (Read 508 times)

Offline markosjal

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Ericsson ringer identification and wiring
« on: December 05, 2016, 04:44:49 PM »
I hace an Ericsson (Mxico) telphone that i can not make ring. I hace included a photo of the bell coil. I suspect it was configured for parte line  and definitely it was configured for divided ringing using a third ground wire on line cord followed by A 70 ohm resistor.

Usually the ringers in these models  use a 33 uf capacitor as this one does have mounted on the board. Because the ringer has multiple contacts , unlike the normal ones with only two, I suspect the ringer was more configurable for party lines , etc.

On a further note from what I have seen Ericsson used compatible parts and compatible wiring on many photo es manufactured in different countries so any Ericsson ringer info may be helpful
Thanks

Mark
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Offline Ktownphoneco

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Re: Ericsson ringer identification and wiring
« Reply #1 on: December 05, 2016, 06:48:42 PM »
I'm not familiar with Ericsson sets beyond the basics, and even less informed about the Mexican telephone system, however, telephone ringers, regardless of who made them, and wired for bridged ringing, are connected across the central office pair, with (usually) tip going directly to one terminal of the ringer, and ring, going to a capacitor.     The other capacitor lead then goes directly to the other ringer terminal.      Your capacitor appears to have a value of 0.33 mfd.     Perhaps another more knowledgeable member of the forum could explain things in a manner more specific to Ericsson and the reason for the additional terminals in the ringer circuit that your describing.      You may want to provide a more detailed picture of the ringer itself, since your making reference to the set having possibly been used in a party line system.       If that is in fact the case, your set may have a frequency ringer installed, and which may not be compatible with your private telephone line's ring frequency.
A diagram of a simple bridged ringing circuit is attached.

Jeff Lamb
 
« Last Edit: December 05, 2016, 08:06:39 PM by Ktownphoneco »

unbeldi

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Re: Ericsson ringer identification and wiring
« Reply #2 on: December 05, 2016, 07:43:24 PM »
I'm not familiar with Ericsson sets beyond the basics, and even less informed about the Mexican telephone system, however, telephone ringers, regardless of who made them, and wired for bridged ringing, are connected across the central office pair, with (usually) tip going directly to one terminal of the ringer, and ring, going to a capacitor.     The other capacitor lead then goes directly to the other ringer terminal.      Your capacitor appears to have a value of 3.3 mfd.     Perhaps another more knowledgeable member of the forum could explain things in a manner more specific to Ericsson and the reason for the additional terminals in the ringer circuit that your describing.      You may want to provide a more detailed picture of the ringer itself, since your making reference to the set having possibly been used in a party line system.       If that is in fact the case, your set may have a frequency ringer installed, and which may not be compatible with your private telephone line's ring frequency.
A diagram of a simple bridged ringing circuit is attached.

Jeff Lamb

That doesn't sound right, Jeff.   3.3 F would be too large.  If I look at that picture, I think I see 0.33 F.

A 3.3 F capacitor would have an impedance of only about 2500 Ω at 20 Hz ringing frequency.  That would be an awful large load on a telephone line and be in serious competition for the current that should go through the rest of the telephone.  At, say 1000 Hz speech, it is only 50 Ω impedance or so.

Offline Ktownphoneco

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Re: Ericsson ringer identification and wiring
« Reply #3 on: December 05, 2016, 07:49:51 PM »
Your right Karl.    I shouldn't try and quickly read things upside down.    Dahh !   Thanks for catching that !

Jeff


 

unbeldi

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Re: Ericsson ringer identification and wiring
« Reply #4 on: December 05, 2016, 07:57:13 PM »
Here is a little reference table of capacitive impedances
at a frequency of 20 Hz ringing current:
0.47 F: 16931 Ω
0.50 F: 15915 Ω
1.00 F:  7958 Ω
2.00 F:  3979 Ω
3.00 F:  2653 Ω
4.00 F:  1989 Ω

For comparison to speech frequencies at 1000 Hz audio frequency, the capacitive impedance is
0.5 F: 318 Ω
1 F: 159 Ω
2 F: 80 Ω
3 F: 53 Ω
4 F: 40 Ω
5 F: 32 Ω


« Last Edit: December 05, 2016, 08:03:13 PM by unbeldi »

Offline Ktownphoneco

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Re: Ericsson ringer identification and wiring
« Reply #5 on: December 05, 2016, 08:16:33 PM »
That's great !   I just copied and pasted your tables into a "pdf" file, and put it into my "Telephone Information" folder.

Thanks Karl !

Jeff

Offline markosjal

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Re: Ericsson ringer identification and wiring
« Reply #6 on: December 08, 2016, 08:51:45 PM »
The only reason I commented about the possibility of a party line ringer as this is the only one of these Ericsson ringers that I have seen with multiple contacts. I suspect it is configurable for a multitude of frequencies.

As I understand it the Cap and ringer coil form a tank circuit.

on the second line of the stamp pictured of base plate you can see what looks like "3X400". Could this reference 3 400 ohm coils in  the ringer?

.33uf capacitor is standard on these. I know WEs, NTs, AEs, use .47uf

ANd technically, this phone is configured for what as I recall is referred to as "divided ringing", using ground wire. (I've never seen this on ericssons from Mexico either, as no ground usually), but it was jumpered to a line wire at the connector that was on the end of the line wire, with a three conductor line wire.

Oh and the resistor near the .33uf Cap is 70 ohms wich seems to be another oddity, especially how it is "Hacked" into place, in series with ringer capacitor and ringer
 
« Last Edit: December 08, 2016, 09:01:59 PM by markosjal »
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