I have lost power on the load side of my new doorbell transformer after a brief period of time when it did power my smart doorbell

Question

I recently purchased a Ring Wired smart doorbell. I needed to replace my original doorbell transformer due to being too small of a voltage output. I first wired the new transformer to the 120v circuit. I checked output on the load side with a multi-meter and had sufficient voltage for the new doorbell. I connected the doorbell and had power to it. I then completed the set up. I had the system up and running for maybe an hour and then discovered that it was not working. I checked the load side of the transformer again with my multi-meter to find out that there no longer was voltage on going to the doorbell. The transformer was fairly warm to touch, definitely warmer than a cell phone charger or laptop power supply. I am concerned that overheating may be causing the transformer to open and not be able to supply power. What would cause this?

Answer 1

Ok you need to have the correct wattage transformer being a little oversized is ok.

So you need ~16vac output or whatever voltage you know that but the transformer needs to be rated for at least 30 VA.

If the rating of the transformer is below or even right at 30va it will get hot and let the magic smoke out (not repairable)

To make sure this doesn’t happen get a transformer a bit larger 40-45 va at 16v The transformer will run cool and last for years / decades if not overloaded.

If your transformer is hot it’s overloaded or mis wired causing an overload thus the heat. Small transformers can produce many times there rating for a while but this creates heat the hotter it gets the less efficient so it gets hotter until the smoke escapes .

The only solution is a larger transformer (keep the voltage the same) VA of a transformer is volts x amps so keeping the voltage the same getting a higher va like 30 or 40 or even 100 allows it to be able to power more if needed but bigger cost so 30-40 va at the rated voltage is the fix you need from what you described.

Answer 2

I am not sure what you had fail. Start by looking at the Ring instructions and make a note of its power requirements, voltage, current, and AC/DC. At this they should both be AC. Next do the same thing with the transformer you purchased. Next check the wiring and be sure it is correct. Is the input voltage to your transformer match what you have. At this point we will assume it is wired properly. Is the transformer output voltage the same as the Ring input voltage, if not replace it. Usually, doorbells are designed to work with about 18% min/max of the specified voltage, I am not sure with the Ring. Is the transformer output current larger than the (Ring current + your chime load) +10% or more. If so keep it. Check the output voltage with your multimeter, it is AC. Is it within +- 10% of its rating, if so it might be OK. Connect the Ring and measure again, if it is low replace the Ring.