# Door Bell Chime Voltage Drop.



## Jayc316 (Jun 30, 2013)

Jayc316 said:


> On a standard doorbell system (16V AC Transformer) the chime my customer has is not loud enough.
> 
> I am reading about 8V AC at the chime when the button is pressed. The transformer in the basement is reading 16V AC, all my joints are tight, I've eliminated the back doorbell button, and I'm ready to replace the existing transformer with another of the same rating.
> 
> ...


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## RandyM (Apr 5, 2012)

Is the transformer big enough? VA rating vary.


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## jmb123 (Jun 19, 2013)

did the kit come with a diode for the door bell button? I bought a kit a few months ago for a customer, and it had tape and was probably returned, but we tried it, and when i finished, it wasnt loud, it sounded blown, you can burn them out pretty easy and I think thats why someone returned this one, and i bought a burnt chime.


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## captkirk (Nov 21, 2007)

How far is the transformer..i cant say i ever had that problem.


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## hardworkingstiff (Jan 22, 2007)

I would check the button for sure, I would also check the cable for a medium resistance short which could cause excessive VD. You know a staple or nail in the wrong place.


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## Introyble (Jul 10, 2010)

Jayc316 said:


> My question is: Should I expect to see the full 16V AC across the chime when the button is pressed, or will the bell solenoid only drop the volts it is using to move the striker?


Are you asking about voltage in a switch when it is open or closed?

When it's open I would suggest you will see full voltage


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## brian john (Mar 11, 2007)

What is the 

Current draw?
Lenght of conductor?
Conduct size?

Do a little math and your question will be answered.


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## dmxtothemax (Jun 15, 2010)

The two most likely problems are -
1 - Too much resistance in the line, bad connecttions / faulty wires / bad switch.
2 - The tranny is not delivering enough current.

You should be able to test no-1 with a multi meter,
for no -2 you need a bigger tranny !


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## Jayc316 (Jun 30, 2013)

Thanks for the troubleshooting leads:

I will check that switch, and testing the conductor resistance on all that old wire in the basement may offer some interesting information.

Like I said, the 16V is at the transformer, just not making it through the wire, push button switch, and getting to the chime.

Another job I will be doing for the thrill of the fight:boxing:, and end up making about .50 cents and hour.

Such is life......


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## readydave8 (Sep 20, 2009)

Yes voltage drops when doorbell rings.

I too have corrected volume problem by changing to higher VA transformer, that's all I had to do the last few times.


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## khfiei (Aug 20, 2011)

If the voltage only drops at the chime and not the transformer when the button is pushed, the problem is the wiring (probably too small a wire size, resulting in voltage drop) and NOT the transformer. A simple solution is to use a transformer with a slightly higher voltage (24 volts), and select a power resistor at the chime to drop excessive voltage so you do not overdrive the chime (a stuck push button could fry the chime coil).


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## Stickshaker (Jun 29, 2012)

Bet you need a 40va instead of a 10.


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## Big John (May 23, 2010)

I also think the most likely cause is an undersized transformer. What's the VA on the transformer? What's the VA on the bell?


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## dmxtothemax (Jun 15, 2010)

khfiei said:


> If the voltage only drops at the chime and not the transformer when the button is pushed, the problem is the wiring (probably too small a wire size, resulting in voltage drop) and NOT the transformer.


NOT TRUE !

It can be either one causing the trouble.
Bad wiring OR underrated tranny !


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## khfiei (Aug 20, 2011)

Please explain your conclusion. If you apply a load equivalent to the chime you are using and connect it AT THE TRANSFORMER and do not observe a voltage drop across the transformer terminals, the problem is in the wiring, etc, after the transformer.


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## dmxtothemax (Jun 15, 2010)

If you measure the voltage of an undersize tranny under no load conditions, it will always be higher than it would be, under loaded conditions.


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## khfiei (Aug 20, 2011)

How do you know that a tranny is undersized under no load conditions? The open circuit voltage of any doorbell transformer will drop a little when a load is applied (I should have stated "significant" voltage drop in my earlier post), but as the OP noted, his situation had 16 volts at the transformer, WITH THE CHIME LOAD, and half that voltage at the chime. Its the wiring.


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## dmxtothemax (Jun 15, 2010)

If you are measuring voltage at the tranny (before the wiring run), and it drops
significantly under load, this is a classic sign that it is being overloaded, which means that the doorbell requires more current then the tranny can deliver, or a leak/short in the wiring run, either way at the moment the set up is asking more current then the existing tranny can deliver.
You need to check what the current draw of the door bell is.
The manufacturer can tell you, or the internet.


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## TreeBaron (May 3, 2013)

Was it run in cat 5? I've seen this done and the installer only used one wire of one of the pairs for the run--- which cannot be done because that Gauge wire is not significant unless joined with other pairs to form a thicker stranded guage.


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## Paulusgnome (Mar 28, 2009)

All of the bell transformers that I have ever dealt with have had incredibly poor voltage regulation, which is to say that their unloaded secondary voltage is usually higher than nameplate rating, and when loaded the voltage sags quite a lot. This seems to be the norm for bell transformers, although it is possible that US-spec bell transformers are better in this respect.
I agree with the other posters - if the secondary voltage is sagging too much for the door chime to operate correctly, you probably need a bigger transformer.


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