Author Topic: 315H ringer - question  (Read 3412 times)

Offline NorthernElectric

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315H ringer - question
« on: February 27, 2015, 08:53:47 AM »
I picked up a 315H subset box with a busted magneto and no ringer.  My plan for this is to make a subset out of it for a D1 using a network from a 2500 and the touch-tone keypad concealed inside.  I think I can make a bracket to mount the modern parts on and attach it with the original magneto screws using the existing holes so I don't have to alter the box.  I would like to get a working ringer with the right size bells.  Is there a ringer that will fit this box without alteration, has the right size bells, and will be compatible with the modern network?
« Last Edit: March 01, 2016, 04:27:27 PM by NorthernElectric »
Cliff

unbeldi

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Re: 315H ringer question
« Reply #1 on: February 27, 2015, 10:14:09 AM »
I picked up a 315H subset box with a busted magneto and no ringer.  My plan for this is to make a subset out of it for a D1 using a network from a 2500 and the touch-tone keypad concealed inside.  I think I can make a bracket to mount the modern parts on and attach it with the original magneto screws using the existing holes so I don't have to alter the box.  I would like to get a working ringer with the right size bells.  Is there a ringer that will fit this box without alteration, has the right size bells, and will be compatible with the modern network?

The 315H was made for a period of almost 30 years, and so it was used with a variety of ringers of the period starting with the early No.2 ringers to the high number like 51A.  When the B-type ringers were developed in the early 30s they eventually also had a model version of that to replace these ringers in wooden boxes.  The advantage of them was they used high-impedance magnet coils and therefore presented a lower ringing load on the lines and caused lower inductive noise on lines.  Since you're connecting the ringer in a bridged configuration the noise problem is not so important actually, but the high impedance is beneficial.  Old 1000 ohm ringers present at least 2.5 REN to your line. The B-type ringers have a DC resistance of 4600 Ω and present about 1.3 REN.  Since you have the choice this is what I would be looking for, however, a B1D or B1E ringer may harder to find. These can mount the original No. 29A bells.

BSP C31.208 Issue 1, June 1954.

Old catalogs prescribe a variety of ringers, e.g., a No. 51AG (1000Ω) in 1915, No. 38AG (1020 Ω), 49AG (2500 Ω), 52AG (3000 Ω) in 1935.  Some samples from my sets: 47B (1600 Ω) ringer,  49B (2 x 1250 Ω) ringer, another with a 46AG.

The ringer also needs a capacitor in series.  A modern, standard variety 470 nF 250V (or higher) capacitor is fine, obtainable from China vendors for pennies.

Offline NorthernElectric

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Re: 315H ringer question
« Reply #2 on: February 27, 2015, 10:38:41 AM »
Thanks unbeldi, this is exactly the sort of information I was looking for.  I suspected there might be numerous ringers that would fit from looking at photos online.

I'm new at this so please bear with me but I have a couple of supplemental questions:

I thought the modern networks such as those used in the 2500 that I am planning to use for this project included a ringer capacitor.  Am I mistaken about that, or are you saying that the built-in capacitor won't be suitable for any of the ringers that would fit my 315H box?

I have seen pictures of ringers where the only markings I could see in the photos were numbers like 500 or 700.  Do these numbers refer to the coil impedance so that the ones with coils marked 500 are 1000 ohm ringers?

How are the B series ringers marked and/or how would I be able to identify one?  Is the shape of the frame enough to go on?

Also, do I have to watch out for tuned ringers that won't ring at 20Hz?

Thanks
« Last Edit: February 27, 2015, 10:40:58 AM by NorthernElectric »
Cliff

unbeldi

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Re: 315H ringer question
« Reply #3 on: February 27, 2015, 11:17:01 AM »
Yes, you are right.   The 425-type networks include that ringing capacitor already.  When I wrote this, I had already forgot that you were going to use an integrated network.  Sorry, didn't mean to confuse.  The capacitor in the network will be perfect as is.

The numbers stamped on those old ringer coils are the D.C. resistance of the coil. They only indicate the general type of ringer, and serve to be able to easily measure (with any multimeter) whether a coil is still good or perhaps has a short somewhere.  The actual impedance under ringing current, which is typically 20 Hz AC current, is much higher.

How high, you can gather from some measurements I published here on the forum in this article if you really want to get into the technical aspects of this.

Re 'tuned ringers':  It is rare to find Western Electric frequency ringers.  Although the Bell System started out with harmonic frequency ringing on party lines, their design was terrible. Using harmonic frequencies (exact multiples of the base frequency) led to problems with multiple ringers ringing, and so eventually they abandoned frequency ringing by probably 1920 or so the latest, in favor of other selective ringing methods.  Other companies, especially the Kellogg Switchboard & Supplies Company redesigned the frequency ringing technology, perfected it, and kept using it even into the 1970s or so.

So, most of these old Western Electric ringers we find operate great between ca. 16 and 25 Hz. My graphs of the measurements show you also how well for example a No. 8 ringer of the time works at various frequencies.

One aspect I would look for when searching for a ringer, is to select one that has a bias spring.  The bias keeps the clapper on one side when no current flows. This prevents bell tapping when the hookswitch is opened or during dialing.  Not all old ringer boxes used biased types.  The reason for this lies in the technical details of different methods of divided selective ringing.
« Last Edit: February 27, 2015, 11:21:58 AM by unbeldi »

Offline NorthernElectric

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Re: 315H ringer question
« Reply #4 on: February 27, 2015, 01:34:25 PM »
Thanks again unbeldi, you've been a big help.  I have bookmarked the link for future reference as well as a topic on REN I found using the forum search.  I will be trying to find a B series ringer but if these are hard to get, I might try others until I find one.
Cliff

unbeldi

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Re: 315H ringer question
« Reply #5 on: February 27, 2015, 01:38:07 PM »
Thanks again unbeldi, you've been a big help.  I have bookmarked the link for future reference as well as a topic on REN I found using the forum search.  I will be trying to find a B series ringer but if these are hard to get, I might try others until I find one.

You may just want to try and post a message in the 'commercial' section here and see if any forum members have some spare parts for sale. We have quite a few here who collect that era of telephone technology.

Offline Babybearjs

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Re: 315H ringer question
« Reply #6 on: February 25, 2016, 01:57:39 AM »
heres a good question.,... I have one of these subsets... in storage and not being used. how often did the bell system take these and mount a 211/212 handset phone on the side of the case and use the subset that way? I'm trying to find out if it would hurt the value of the 315H if I added a non standard part to it.... unless they used to do this all the time.
John

Offline NorthernElectric

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Re: 315H ringer question
« Reply #7 on: February 25, 2016, 12:20:05 PM »
heres a good question.,... I have one of these subsets... in storage and not being used. how often did the bell system take these and mount a 211/212 handset phone on the side of the case and use the subset that way?

My 315H wasn't used this way, but I have an N515H that was and I have seen others.  I couldn't say just how common a practice this was.

I'm trying to find out if it would hurt the value of the 315H if I added a non standard part to it.... unless they used to do this all the time.

I don't know for sure, but it's my impression that the supply of local battery magneto subsets exceeds the demand (in Canada especially) and therefore the market value for these is not all that high to begin with. 
Cliff

Offline Babybearjs

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Re: 315H ringer question
« Reply #8 on: February 25, 2016, 08:21:00 PM »
thanks for the reply Ben.... you know anything about the #2 Uniphone? I just got one from Phonestuff In Florida... $18.88! no one bid on it so, I grabbed it... Pictures to follow...(If they post....)
John

Offline Sargeguy

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Re: 315H ringer question
« Reply #9 on: February 25, 2016, 11:38:29 PM »
315H subsets are pretty cheap-they are worth less than the sum of their parts.  A magneto taken from a 315 will usually fetch more than the entire 315.  I have a stack of them if anyone is looking for one.
Greg Sargeant
Providence, RI
TCI /ATCA #4409