# 2 doorbell chimes 1 transformer?



## truelight (Mar 17, 2010)

Hey guys,
does anyone know how to make 2 doorbell chimes work off of 1 button and 1 transformer? the trans the chimes are 16v each and say use only a 16v trans with it. 1 chime works, but when i tried to go through the 2nd in series (i think) it would not go. Can i try a 24v trans? Has anyone ever done this before?
Thanks,
Mike - Truelight Electric Inc


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## MDShunk (Jan 7, 2007)

No, you need more vA, not more volts. They sell chime transformers in larger physical sizes . That's what you need to drive 2 or more chimes. The 10vA chime transformer that comes with the kit will not work.


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## Bob Badger (Apr 19, 2009)

MDShunk said:


> No, you need more vA,





truelight said:


> but when i tried to go through the 2nd in series (i think)


He will still need to make sure the two chimes are in parallel.


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## macmikeman (Jan 23, 2007)

Run some 3/0 for the wiring, that ought to help with the vd. :thumbsup:


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## Bob Badger (Apr 19, 2009)

macmikeman said:


> Run some 3/0 for the wiring, that ought to help with the vd. :thumbsup:


Man I want to see you get the buttons to sit right with a pair 3/0s on them. :jester:


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## Dennis Alwon (May 9, 2009)

My supplier has a small transformer- the size of the standard bell transformer (10v) that is 30 va. This will drive two chimes quite well. 

And yes, the chimes must be wired in parallel.

A 24v trany will probably work, if it is the right va, but it will burn the light out in the doorbell button.


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## Comingler (Jun 4, 2010)

Bob Badger said:


> Man I want to see you get the buttons to sit right with a pair 3/0s on them. :jester:


:laughing::laughing: I could barely get those tiny screws/nails into the wood with bell wire attached :thumbup:


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## macmikeman (Jan 23, 2007)

Comingler said:


> :laughing::laughing: I could barely get those tiny screws/nails into the wood with bell wire attached :thumbup:


Ask me how many times I managed to poke a hole in my fingers trying to install those teeny cheap brass colored screws they package with the doorbell buttons...


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## idontknow (Jul 18, 2009)

macmikeman said:


> Ask me how many times I managed to poke a hole in my fingers trying to install those teeny cheap brass colored screws they package with the doorbell buttons...



So, how many times have you managed to poke a hole in your fingers trying to install those teeny cheap brass colored screws they package with the doorbell buttons?


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## macmikeman (Jan 23, 2007)

idontknow said:


> So, how many times have you managed to poke a hole in your fingers trying to install those teeny cheap brass colored screws they package with the doorbell buttons?


Ugh maybe twice, three at most....


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## jarhead0531 (Jun 1, 2010)

As already state you need 10VA for every chime, none of my suppliers had any, nor did HD or lowes. I ended up opening the cheaper bell packages until I found one that came with a 20VA transformer and that worked. To boot it was actually cheaper than buying a transformer by itself.


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## idontknow (Jul 18, 2009)

jarhead0531 said:


> As already state you need 10VA for every chime, none of my suppliers had any, nor did HD or lowes. I ended up opening the cheaper bell packages until I found one that came with a 20VA transformer and that worked. To boot it was actually cheaper than buying a transformer by itself.


You could always wire up 2 transformers in parallel.

That'll never fail.


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## MDShunk (Jan 7, 2007)

idontknow said:


> You could always wire up 2 transformers in parallel.
> 
> That'll never fail.


Actually, you'll have them running pretty darned hot. The sine wave on the secondary side isn't exactly the same, and they'll either add or buck each other a tiny bit. Been down this road many times with HVAC control transformers.


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## Bob Badger (Apr 19, 2009)

MDShunk said:


> Actually, you'll have them running pretty darned hot. The sine wave on the secondary side isn't exactly the same, and they'll either add or buck each other a tiny bit. Been down this road many times with HVAC control transformers.


You sure?

One could be 180 from the other but swapping the polarity would fix it.


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## MDShunk (Jan 7, 2007)

Bob Badger said:


> You sure?
> 
> One could be 180 from the other but swapping the polarity would fix it.


Yeah. I've actually troubleshot this with a scope and overlaid the waveforms. The sine waves on the output are never close enough. Heating will be the result.


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## Bob Badger (Apr 19, 2009)

MDShunk said:


> Yeah. I've actually troubleshot this with a scope and overlaid the waveforms. The sine waves on the output are never close enough. Heating will be the result.


Why, it is common for large transformers to operated in parallel .... no?


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## Geoff C (May 26, 2010)

wally world

http://www.walmart.com/ip/Door-Bell...ci_src=14110944&ci_sku=11370873#ProductDetail


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## macmikeman (Jan 23, 2007)

Bob Badger said:


> Why, it is common for large transformers to operated in parallel .... no?


I did that hookup once. Matched the impedence. Actually I bought duplicate trannys of the same model number. But I am no MD Shunk or Bob Badger level of smarts so I will admit right now, I was freaking shaking with fear of the unknown the moment I first threw the switch to on...


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## MDShunk (Jan 7, 2007)

Bob Badger said:


> Why, it is common for large transformers to operated in parallel .... no?


Sure, but the tolerances on chime transformers and HVAC transformers are not close enough, even in the same brand and model. If they're two different transformers, forget about it. You can do it with power transformers because the tolerances are so much greater. Even better if you order them with a notation that you want them impedance matched to parallel them.


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## Electric Al (Mar 13, 2010)

Why not do it the easy way? Buy a 30 va transformer. Problem solved !! :yes:


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## MDShunk (Jan 7, 2007)

Electric Al said:


> Why not do it the easy way? Buy a 30 va transformer. Problem solved !! :yes:


Exactly.

Really, the only time you should think about paralleling transformers, in my opinion, is in industry where the correct single transformer would be 6 months to a year special order from ABB or Seimens. They can parallel off the shelf transformers instead. Even at that, the measured impedances (not nameplate) are supposed to be within 1/2%. If one transformer is 7%, the other should be between 6.965% and 7.035%


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## 220/221 (Sep 25, 2007)

Electric Al said:


> Why not do it the easy way? Buy a 30 va transformer. Problem solved !! :yes:


That might not be the easy way. 

I stock standard transformers/chimes on the truck. If a customer asks me to add another chime while I'm there, it is easier to install two transformers than to go find an odd transformer.


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## jarhead0531 (Jun 1, 2010)

220/221 said:


> That might not be the easy way.
> 
> I stock standard transformers/chimes on the truck. If a customer asks me to add another chime while I'm there, it is easier to install two transformers than to go find an odd transformer.



That would be fine if it was two chimes on two buttons but that wouldn't work with a 1 button, 2 chimes scenerio.


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## Dennis Alwon (May 9, 2009)

30 va transformer are stock items at my supply company as we often have 2 chimes in a house.


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## MDShunk (Jan 7, 2007)

jarhead0531 said:


> That would be fine if it was two chimes on two buttons but that wouldn't work with a 1 button, 2 chimes scenerio.


Actually, it does work, but I don't happen to think it's a good idea.

The only chime transformer I carry on the truck for replacement is the larger one. I end up with extras of the smaller one's completely as surplus from chime kits where I didn't use the small transformer.


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## jarhead0531 (Jun 1, 2010)

MDShunk said:


> Actually, it does work, but I don't happen to think it's a good idea.
> 
> The only chime transformer I carry on the truck for replacement is the larger one. I end up with extras of the smaller one's completely as surplus from chime kits where I didn't use the small transformer.


I'm assuming it is a bad idea because it will parallel the transformers, making things toasty. Never thought to parallel them myself anyway, always just picked up the larger transformer.

Pardon my stupidity as I haven't messed with low voltage like that in some time. Seems like most people just buy the wireless chimes now to make life easier and cheaper.


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## Heymanisth (Apr 20, 2010)

3/0, are you stupid? Way over sized and way too much money... 1/0 is fine.


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