Is it normal for a doorbell transformer to be warm and make noise?

Question

To make a long story short I am in the process of hooking up my ring door bell and I need to follow these instructions: (I want to wire directly to transformer)

To my understanding I need to wire my doorbell wiring directly to a 8-24V transformer which has a resistor following their specs.

• For my resistor I used this product

• For my transformer I used this product

I went ahead and tapped into a junction box which has some 14-2 Wiring - I hooked the transformer into those. I then souldered the resistor onto my doorbell wiring and hooked up my doorbell wiring to the transformer (distributing 16v to my ring doorbell)

I have three questions:

1. the transformer is pretty warm to the touch....Not crazy hot but deff warm. Is this normal for a transformer? Or do I have to much power being distributed to it?

2. the transformer makes a decent amount of noise. The transformer had the built in clip with the screw (it just goes right into a pop out in the box) but it’s not very secure? I am assuming the noise is from the vibration of it not being very secure to the box. (Also if I hold it down by hand there is still some light noise)

3. I guess my overall concern is I understand the very (and I mean very) basics of a transformer and resistor. But are the above items normal? Should a transformer be silent and cool? Based on my set up is there any red flags?

Answer 1

the transformer is pretty warm to the touch....Not crazy hot but deff warm. Is this normal for a transformer?

A loaded transformer should be about as warm as your laptop charger. On the conceptual level, they do essentially same thing. (the transformer is less efficient, but the laptop charger puts much more power so the waste heat should be similar)

Or do I have to much power being distributed to it?

The only way of giving it too much power would be wiring a 110V transformer (yours) to a 220V circuit. Or wiring it backwards, but that would have blown up already.

the transformer makes a decent amount of noise.

That's bit concerning. A transformer should emit mains hum, but it should be very faint, impossible to hear from a distance. On a busy day, you should have to put your ear to it in order to notice the sound, easier to feel by hand. Unless something is acting as sound amplifier (like a guitar body), eg. being fixed to a drywall or lying on a desk.

I guess my overall concern is I understand the very (and I mean very) basics of a transformer and resistor. But are the above items normal? Should a transformer be silent and cool? Based on my set up is there any red flags?

The phenomena you're describing are fundamentally normal, but it's impossible to tell from your description if the intensity is normal as well. Cheaply made, loose transformer will make much more noise than a decent unit.

Generally, when dealing with a new circuit, the best course is to assemble and run it on a bench first. In stages. You should observe the transformer running at idle (without any load), with almost-idle load (videobell fully charged), with small load (the videobell charging through the resistor) and at full load (with the bell button depressed / the resistor hooked up directly). The sound and heat of the transformer change with load. The heat load of your resistor also change, depending if the button is pressed. You could try using the 8, 16 or 24V taps to see which one works best. Contra-intuitively, using higher voltage sometimes resuls in smaller losses when charging an electronic device. You could try to use 2 resistors in series (you've linked a 2-pack), especially with 16 or 24V. Even a cheapest multimeter would help greatly to ensure you get expected voltages. (Within a healthy margin, certainly. A doorbell transformer is not meant to be precise.)

The most important question would be: is the videobell charging? All of your issues could be easily explained if some of the output terminals are shorted, overloading the transformer. The unused terminal should be left unconnected.

Ring uses 30VA transformer on their examples, yours has only 10VA on 8 and 16V circuits and 20VA on 24V - but that's definitely not a problem here. With 25ohm resistor, the power always stays within the limits. On 8V it's merely 2 watts (you can assume that 1VA = 1W in this case).

Answer 2

1. Transformers are always going to produce some heat. It's a part of the step-down process. It should only be warm to the touch, however. If it burns you, there's something seriously wrong.

2. Some noise is not unusual either. Go stand near a power company transformer and you should hear some noise as well. If the transformer is cheap, it might make more noise than a more expensive model (my experience only, yours may differ), but they generally aren't silent. #1 would worry me more than this

Answer 3

On the heat check the specs on the ring doorbell and make sure 20VA is enough to cover what the required VA needed. It should tell you either the wattage or the VA it uses. VA is volt-amps or volts times amps or wattage. (12 volts x 1.6 amps equals 19.2VA, 24 volts x .83 amps equals 20VA). You shouldn't go over 80% of the rating of your transformer or in your case 16VA. Transformers that are magnetic are going to create heat. Just don't overload.

Answer 4

So did you have an existing traditional doorbell already and you are just adding the Ring unit to that circuit? because THAT is the only time you need the resistor. The resistor is there to protect the Ring unit from the effects of having an older electro-mechanical bell circuit on the same line; they are notoriously 'nasty" in terms of electrical noise due to a phenomenon called "inductive kickback". When the doorbell mechanism is the only thing there, nobody cares but if you connect the Ring unit to the same existing circuit, tat inductive kickback sends little pulses of voltage back on the line that may end up destroying the Ring unit. If you don't have an old system still in place and are just using the phone connectivity as your "bell", you don't need that resistor. Ring worded that poorly, you are not the only one who misinterpreted it.

The thing is, adding that resistor must also be done correctly, meaning it must be in SERIES with the Ring unit circuit. If you connect it in PARALLEL, it presents a 50W load burden on the transformer and that transformer cannot handle 50W!