Oh that makes sense. Thanks!
Doorbell wiring
- Thread starter minesh21
- Start date
- Status
Oh that makes sense. Thanks!
So you think I'll have a problem when installing the Ring Pro in regarding to sufficient voltage to start the unit? Ring says they need 16V, but the transformer is only rated for 16V and the chime will need some power so I think I need to upgrade the transformer right? To maybe a 24V unit?
The link was very helpful thanks!
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
No, I believe it will work fine. I have installed a few, and have had no issues.
junkhound
Senior Member
- Location
- Renton, WA
- Occupation
- EE, power electronics specialty
Oh my! You should have read the rest.
Following is just observation, not criticism.
If you can actually tell the difference between a diode and a resistor and text with the photos was a typo, the details given in gar's post would tell you exactly why you measured what you did - esp as you were measuring across a diode.
BTW, my youngest son AND his wife both have EE degrees from UW and son also has computer science degree - lots of $$ income from digital work. Someitimes in discussions with them on some aerospace power problems I've encountered I'm amazed at some of the analog and power knowledge they are missing. You seem to be missing the same type .. makes one wonder what other basic universities leave out to cram in all the digital information.
Please go back and read the rest of gar's post to educate yourself.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
I'm pretty sure that you cannot just read the voltage across the two terminals on the push button switch because it is in series with the chime (load). You need to depress the switch and read the voltage across the chime terminals.
I had one job where I needed to install a 30va transformer for the Ring to work.
kwired
Electron manager
- Location
- NE Nebraska
It it parallel across the button switch.
In a state of rest the diode is a half wave rectifier - pulsing DC is returning to your controller, and probably is what your measured 14 volts was, try switching your meter to DC and see what it says. Pressing button will shunt across the diode and full wave AC will return to your controller.
Can't say I know any more about how your controller works, but apparently that AC signal starts the ring process, and possibly presence of the pulsing DC signal allows the programmed ring cycle to continue. Maybe if you took the diode off, you would have to press and hold the button to keep the chime playing.
Haven't dealt with many electronic chimes. But for the typical solenoid type chimes - 16v is the typical nominal voltage. Many are wired with 18, 20 or even 22 AWG conductor, has to be some voltage drop in those - especially when the solenoid is pulling in, but at same time they are not designed to be anything but a brief load and coils burn up easily (solenoid or transformer) if the switch is closed for too long.
gar
Senior Member
- Location
- Ann Arbor, Michigan
- Occupation
- EE
180505-1253 EDT
minesh21:
I ran some experimentx on two different small transformers.
The first one is a 1958 or 1959 Nutone Inc., 24 V, Chime Transformer, Cap 20 VA, Made in USA, UL. No other information. One assumes 120 V input, but still might have been 117, not likely 115, and by this time not 110. The EI core on the outside reads 2.63" x 2.21" x 0.94".
57.2 ohms is primary DC rrsistance.
3.0 ohms is secondary DC resistance. 62.1 is estimatre of secondary reflected to primary. Thus, 119 ohms is total seen at primary with secondary shorted. A close comparison with 127 below. But there needs to be some additional equivalent resistance added for core loss power.
Using a Kill-A-Watt EZ and a Fluke 27 the measurements were:
Open secondary with no load,
119.8 V, 0.02 A, 1.4 W, 2.6 VA, 0.53 PF, secondary 26.4 V.
Shorted secondary with reduced input voltage. 70 V is about lowest with EZ.
70.0 V, 0.55 A, 38 W, 38 VA, 1.00 PF. Apparrent input resistance 127 ohms.
With nominal 120 V input and various secondary loads:
57.5 ohms ---
119.7 V, 0.10 A, 12.2 W, 12.2 VA, 1.00 PF, secondary 24.0 V.
............... --- load power 10.0 W, eff is 82%.
............... --- Approx source impedance of sec 2.6/(24/57.5) = 6.2 ohms.
26.5 ohms ---
120.7 V, 0.20 A, 24.4 W, 24.4 VA, 1.00 PF, secondary 21.5 V.
............... --- load power 17.4 W, eff is 71%.
............... --- Approx source impedance of sec 4.9/(21.5/26.5) = 6.04 ohms.
With an estimated turns ratio of 4.55 the approx secondary source impedance of 6.04 reflects to the primary as 6.04*4.55*4.55 = 125 ohms. We seem to have fairly good corrrelations.
What is apparent is that this transformer has been designed with a high internal resistance compared to its leakage inductance. Besides the PF of 1 showing on the Kill-A-Watt EZ scope traces show current and voltage very close to in phase.
My expectation was that a current limiting transformer would have been designed with a high leakage inductance to resistance ratio. This Nutone was obviously not.
I will get back to data on the other transfotmer later. It is designed for rectifier power supplies, and does show substantial leakage inductancre compared to its winding resistance. It is a newer transformer and has less iron and lower resistance, but its VA is higher at 30.
The transformer of post #1 appears to have a large internal impedance, and for current limiting that is what you want.
.
minesh21:
I ran some experimentx on two different small transformers.
The first one is a 1958 or 1959 Nutone Inc., 24 V, Chime Transformer, Cap 20 VA, Made in USA, UL. No other information. One assumes 120 V input, but still might have been 117, not likely 115, and by this time not 110. The EI core on the outside reads 2.63" x 2.21" x 0.94".
57.2 ohms is primary DC rrsistance.
3.0 ohms is secondary DC resistance. 62.1 is estimatre of secondary reflected to primary. Thus, 119 ohms is total seen at primary with secondary shorted. A close comparison with 127 below. But there needs to be some additional equivalent resistance added for core loss power.
Using a Kill-A-Watt EZ and a Fluke 27 the measurements were:
Open secondary with no load,
119.8 V, 0.02 A, 1.4 W, 2.6 VA, 0.53 PF, secondary 26.4 V.
Shorted secondary with reduced input voltage. 70 V is about lowest with EZ.
70.0 V, 0.55 A, 38 W, 38 VA, 1.00 PF. Apparrent input resistance 127 ohms.
With nominal 120 V input and various secondary loads:
57.5 ohms ---
119.7 V, 0.10 A, 12.2 W, 12.2 VA, 1.00 PF, secondary 24.0 V.
............... --- load power 10.0 W, eff is 82%.
............... --- Approx source impedance of sec 2.6/(24/57.5) = 6.2 ohms.
26.5 ohms ---
120.7 V, 0.20 A, 24.4 W, 24.4 VA, 1.00 PF, secondary 21.5 V.
............... --- load power 17.4 W, eff is 71%.
............... --- Approx source impedance of sec 4.9/(21.5/26.5) = 6.04 ohms.
With an estimated turns ratio of 4.55 the approx secondary source impedance of 6.04 reflects to the primary as 6.04*4.55*4.55 = 125 ohms. We seem to have fairly good corrrelations.
What is apparent is that this transformer has been designed with a high internal resistance compared to its leakage inductance. Besides the PF of 1 showing on the Kill-A-Watt EZ scope traces show current and voltage very close to in phase.
My expectation was that a current limiting transformer would have been designed with a high leakage inductance to resistance ratio. This Nutone was obviously not.
I will get back to data on the other transfotmer later. It is designed for rectifier power supplies, and does show substantial leakage inductancre compared to its winding resistance. It is a newer transformer and has less iron and lower resistance, but its VA is higher at 30.
The transformer of post #1 appears to have a large internal impedance, and for current limiting that is what you want.
.
kwired
Electron manager
- Location
- NE Nebraska
True wireless door bell is the barking variety.:happyyes:
I haven't been to many places with electronic wireless doorbells where anyone answers the door after pressing the button - knock on the door and they answer. Maybe they just need batteries, but are worthless if they never work.
We have the barking variety too. He also alerts us to the phone ringing and is an excellent intruder alarm.
But I take your point about the batteries.
hbiss
EC, Westchester, New York NEC: 2014
- Location
- Hawthorne, New York NEC: 2014
- Occupation
- EC
The diode in parallel with the button provides a constant DC to the chime that can be fed through another diode facing the same way or better yet, a FWB, filtered and used to constantly power the electronics.
Pressing the button shunts the diode at the back of the button and sends full AC to the chime. A diode, connected in opposite polarity to the one at the button located in the chime off the button "switched" will provide a DC pulse whenever the button is pushed and that is used to trigger the chime. This simply allows the existing wires from the button to the doorbell to the transformer to be used without modification.
-Hal
kwired
Electron manager
- Location
- NE Nebraska
Seems the modification is you need to add the diode. I don't see why they can't build the unit so that all you need is a pair to a switch that is a trigger for the chime.
But then old garage door openers used to use a simple dry contact for a wall control but most new ones must be compatible with the operator anymore. Makes some sense if it has extra functions being carried over just one pair, but even a simple single button won't work anymore if it isn't the right unit to go with the opener
They call that security features - IMO if someone is already inside the garage - so what? I can understand better security that is built into the wireless remotes/receivers that wasn't there in the past.- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
You could use a switch leg to the button and a constant feed from the transformer to the chime. Fine for new construction, but old work may not give you the three or four wires you need at the chime location.Seems the modification is you need to add the diode. I don't see why they can't build the unit so that all you need is a pair to a switch that is a trigger for the chime.
But then old garage door openers used to use a simple dry contact for a wall control but most new ones must be compatible with the operator anymore. Makes some sense if it has extra functions being carried over just one pair, but even a simple single button won't work anymore if it isn't the right unit to go with the opener
You often have two wires from transformer to chime and two from transformer to button.
The diode circuit allows you to work with that.
Sent from my XT1585 using Tapatalk
Last edited:
kwired
Electron manager
- Location
- NE Nebraska
People around here (that know what they are doing) have always run a feed from transformer to chime and switch leg to the button, often have two door setup and run second switch leg also from the chime.
It is the HO's and handymen that foul things up by running from transformer to button and then to chime - usually with no room to make any connections at the button :blink:
Bad enough with just a two wire cable at button anymore because with spray foam insulation that wire won't push in or pull out anymore - used to depend on leaving extra wire and pushing it in the wall after making up the button, sure makes future button servicing/change out easier. Am considering making some sort of pocket in the wall so after they insulate there is still a void to push cable into. Might even work to just nail a device box with opening right against the wall sheathing but not cutting it out. They can foam it all they want.
gar
Senior Member
- Location
- Ann Arbor, Michigan
- Occupation
- EE
180505-2005 EDT
So far I have seen no explanation of why anything other than a SPST spring return pushbutton is required other than for some special system. The special system may be for the sole purpose to sell an expensive pushbutton. A signaling device, whether a buzzer or electronic, does not require anything other than a switch closure unless the load current is too high.
Further most doorbells are not used by the person wanting your attention because most don't work.
My pushbuttons and bell work, but still many people still knock.
.
So far I have seen no explanation of why anything other than a SPST spring return pushbutton is required other than for some special system. The special system may be for the sole purpose to sell an expensive pushbutton. A signaling device, whether a buzzer or electronic, does not require anything other than a switch closure unless the load current is too high.
Further most doorbells are not used by the person wanting your attention because most don't work.
My pushbuttons and bell work, but still many people still knock.
.
gar
Senior Member
- Location
- Ann Arbor, Michigan
- Occupation
- EE
180505-2259
Besoeker:
Some of my neighbors have video doorbells with voice communication.
.
Besoeker:
Some of my neighbors have video doorbells with voice communication.
.
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
- Status