Just setup a ring door bell with a 40vac transformer and a 50w 25ohm resistor in the doorbell circuit. Seems to work, but the doorbell circuit is drawing close to an amp.

I am puzzled as to what is in the ring doorbell that draws that much power? The battery in the doorbell holds a charge for months, so it can’t be the steady state operation of the doorbell that is drawing that much power.

 

40vac seems high.
Most doorbells I've seen run on appx 16vac.
Ring mentions 8 to 24vac as normal..
The Pro model 16 to 24vac.

 

I assume your 25 Ohm 50 Watt resistor is in series with your transformer and not in parallel with it?

Ron

 

What is the 25Ω resistor doing?
If you are trying to reduce the 40Vac to 28Vac with that resistor in series with the ring or in parallel, that's likely the problem.

 

First: I DON'T KNOW.
Second, it may be drawing more power than you expect because the battery is charging.
Third, I agree 40VAC sounds high.

 

Standard wiring diagram.

 

I assume your 25 Ohm 50 Watt resistor is in series with your transformer and not in parallel with it?

Ron

Yes it is in series. Between the transtormer terminal and one leg of the doorbell wiring

 

Since the maximum recommended Ring voltage is 24Vac, why did you think 40Vac is okay?

 

Standard wiring diagram.
View attachment 342821

What is the 25Ω resistor doing?
If you are trying to reduce the 40Vac to 28Vac with that resistor in series with the ring or in parallel, that's likely the problem.

My first attempt was transformer directly to bell, no resistor. Transformer heated up in about 5 minutes and blew out the primary side (thermal fuse I suspect) . Searched through ring documents and came across instructions that said to include the resistor in series with the bell circuit.

 

Since the maximum recommended Ring voltage is 24Vac, why did you think 40Vac is okay?

40vac is what the ring manual specifies. The transformer will only output whatever the bell draws.

 

40vac is max.
Should only draw the current when the button is pressed.
The resistor is there to simulate the series chime or standard doorbell.
1 amp is pretty much normal for these devices.
I suspect the voltage output on the transformer is dropping to appx 25vac when loaded.

 

1 Amp does sound too high, though I wouldn't use a transformer greater than 24V AC (as the diagram suggests). Power draw (allegedly) is 1-3 W when idle, 3-5 W in active mode and up to 10W when charging. Assuming this is with 24V AC then the current should no more than 150mA in idle, 220mA active and 0.5A charging Each mode will produce a different drop across the resistor. If the power draw was 1W then the voltage on the Ring (with a 40V AC transformer and 25 Ohm resistor) would be 39.4V, no idea whether this may damage anything.

 

The manual does not call for 40 VAC, it calls for 40VA. Big difference!

 

VAC = Volts Alternating Current
VA = Volt*Amps (a.k.a Volts times Amps)

rick.curl do you have a manual? A link to a manual?

 

Look here: https://ring.com/support/articles/ctz2i/Installing-your-Ring-Video-Doorbell-Wired
If you have already connected the doorbell to 40 VAC it is likely damaged.

 

Look here: https://ring.com/support/articles/ctz2i/Installing-your-Ring-Video-Doorbell-Wired

[edit] This is a snippet from the manufacturers manual: [end edit]
And there it is. 10 to 24 volts AC. 20 - 40 VA (Volt Amps, not volts)

 

I think theRing doorbell is designed to work with an existing doorbell in series with it. I think when used with a transformer of less then 24 volts it only draws a very small current which is not enough to cause the existing bell to ring. I think it may have a protection circuit in it to clamp the voltage across its terminals to about 25 volts. I think this is probably the cause of the high current draw with the 40 volt transformer. Measure the current using a 24 volt transformer instead of the 40 volt one. Why did you choose to use a 40 volt transformer when 24 volts is the doorbells maximum rating.
Les.

 

I think the Ring doorbell is designed to work with an existing doorbell in series with it.

The first generation Ring doorbells worked either way.
If you removed the existing doorbell or it was a new installation without the conventional doorbell the 25 ohm resistor was required.
This is to limit the current which is appx 1 amp when the button is pressed with a 24vac transformer.
The resistor simulates appx the same load as a conventional doorbell.

 

It appears that the problem originated because some fool used "VA" instead of watts. Thile VA is probably more correct it is really a poor choice to confuse folks.
AND, what sort of doorbell would use 40 watts??? Think about THAT!!
That is more current than an 8 inch fire alarm bell uses.

And so a 40 volt transformer is probably a fire hazard at best. Take it out and use a 16 or 20 volt transformer.
AND a series resistor provides no voltage drop until some current flows.

 

In post #16 I cut and pasted a section from the user manual which specifies using a transformer that is 20 to 40VA max. The confusion may be coming from the manual. It also states in post #16 that the proper voltage is 10 to 24 VAC. And as Was specified in post #14 clarification was made for the benefit of the TS as to the difference between VAC and VA. While I agree with @MisterBill2 that VA is somewhat confusing I've found that when I've used "Watts" instead of "VA" I've gotten criticized for the improper use. Yes, I know the difference. Watts is a DC thing whereas VA is an AC thing. AC is something I'm less familiar with in terms of VA and may from time to time use Watts in place of VA, I acknowledge that VA "IS" the correct usage based on the snippet posted from the manual in post #16. I did not wish to use "Watts" for fear of being pointed at.