Another Doorbell Question

[lowefficiency]

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>> The Goldilocks power level seems to be 8 volts for the ringer. 12 is too much, 5 not enough (going off of miscellaneous power converters I had laying around).
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>> Rich, I already tested the ringer with various transformers and got no ringer action with anything other than 8v.
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Based on these two statements, I think you are focused on 8V being a necessity, when the problem is likely elsewhere.

These buzzer-based ringers should operate on a fairly wide range of voltages, it will just be a more vigorous ringing if the voltage is higher. The fact that it didn't ring at 12V likely means that your 12V supply wasn't providing an adequate current, NOT that the ringer can't tolerate or isn't happy with 12V.

When wiring a circuit like this, you don't want to cut it too close to the minimum voltage that will operate the ringer, as that leaves you very little breathing room for oxidized contacts in the switch, old connections, etc. You may find that your ringer works fine for you when you test it, but visitors mention that the bell doesn't work, just because of the firm way in which you pushed the button. A little extra voltage will ensure reliable ringing in these less-than-optimal conditions.

 

[rp2813]

Bud, thanks for that link.  It's worth the $7 & change to order that transformer and see if it resolves the issue.  I've got a watch on it for now.

 

Thanks Dave.  That's something to consider.   I wouldn't mind if the ringing was a little more vigorous/louder than it is currently.

 

I'll take another look at the other transformers I tested the ringer with and see if maybe they were DC.  What I do know is that when I tried to install the ringer using the existing transformer (because I didn't know where it was located yet), I got nothing.  I assume that transformer is 22 - 24v.  I can't find any markings on it that indicate its output.

 

Wouldn't you know it -- the next door neighbor came to the door a little while ago and had to knock a few times because the ringer isn't working . . .

 

[sfh074]

it actually

comes down to current. If you are driving a bell that needs an amp or more then you're killing yourself trying to figure out the correct voltage using small wall adapters. I would say 10-12 volts and at least 2 amps to push 30' of small bell wire. Since it is a momentarily circuit a little bit higher voltage would be ok, but you need a couple of amps to drive the bell ringer and make up for the voltage drop.

 

[tolivac]

DC doorbells were usually powered by dry cell batteries.Would have been an OLD system that was used before AC power.Remember those large vertical 1.5V dry cell batteries with the clip terminals on the top?Those were used for old doorbells.

 

[rp2813]

I checked the existing transformer for the plunger chime.  It's a DH910 and has options for three voltages:

 

Output 10VA at 8 Volt and 16 Volts; 20VA at 24 Volt.

 

I decided to try it with the 8 Volt/10 VA wire configuration and the clapper didn't budge.   We  were expecting visitors today so I wired the transformer to operate the chime again and that's how things currently stand.  16v doesn't work, as that's what the chime operates on, and the first time I tried to hook up the ringer, I was using the existing transformer as wired for the chime.

 

This ringer seems to be very finicky about voltage.  Here's a shot of its coil:

 

 

[sfh074]

Ok, ok ......

It is DC operated. Single coil, with breaking switch. When no voltage applied the switch is closed allowing current to the coil. When current applied, the coil pulls on the clapper, rings the bell and the switch opens, in turn allows the clapper to return to zero ..... the switch closes and the process starts over.

Based on the size of the wire of the coil, it will need a fair amount of current. I'm thinking your 8v supply has enough current to make it work whereas your other supplies may be of greater voltage but do not push enough current to operate the mechanism.

So I'm going to go with battery operated, low voltage but high current requirements. Polarity is also important. You'll have it correctly connected when the clapper is pulled towards the bell. To test this idea, an easy way would be to try one of those old school 6v lantern battery. If that doesn’t do it, then try 2 of them in series. One other thing to note, the switch gap is important. Too wide or too close and it won't oscillate continuously.

 

[rp2813]

Cool -- more good information, Bud!   I'm glad I posted the coil picture.  I'm going to guess that it's unwise to try and configure the wires on the transformer for 8-Volt/20VA (if that's even possible).  I'll do more research on the DH910 to see if its output is AC or DC.

 

If possible, can you explain what the "VA" means, and what I should look for in transformer specs? 

 

I guess I can take the 10-volt ebay transformer off of my watch list since its output is AC.

 

[sfh074]

all that I can suggest

is a transformer that produces d_c output with a higher current. I would suggest something around 10 to 12 volts DC but with a higher current at least 3 amps minimum. This will also help to contend with the voltage drop of the 30 foot of small bell wire. again I would suggest trying an experiment with the 6 volt lantern batteries and hooking it up in the 30-foot wire.

 

[rp2813]

OK, I'll see what I can find with those specs.

 

My 30' calculation is a rough estimate, since it appears to me that the routing from the electrical box to the doorbell switch may be 15' and from the switch to the bell another 15'. 

 

The wire appears to be perhaps twice the gauge of bell wire, but I'm not sure of its exact size.

 

[sudsmaster]

Ralph,

VA means volt-amps. It's a simple equation: volts times amps. It is used instead of watts to indicate the power in a circuit, as it takes into account losses due to inductance.

What you really need is a shop or lab with a variable DC transformer so the ideal voltage/amperage for this ringer can be determined. There ought to be some electronics shops in your area that could do this for you.

It's also possible the ringer itself is compromised in some way. Weak spring comes to mind. I don't know.

Personally I'd go to HD or Ace or Lowe's and pick up a high quality doorbell system and be done with it. But then you'd lose the vintage aspect. C'est la vie...