doorbell

[Jan]

Here's my problem, I replaced a buzzer style door chime with a regular chime because the client hated the sound. Now when the button is pushed the chime sounds and it's followed by a buzz. What's up with this? The transformer is attached to a jbox and the chime and button were wired in phone wire. I have bypassed the switch and still get the same result. Any idea's

 

[kwired]

Most doorbell chimes are pretty inexpensively made core and coil devices - they will hum or buzz when energized.

If your customer can't stand the buzz get an electronic chime.

ETA: the fact it was wired with phone wire could be contributing some voltage drop adding to the problem.

 

[hurk27]

If you have replaced an old solenoid chime and the new one is electronic it should have come with a couple diodes to put on the door bell buttons some units require a diode at each button and some only require one at one of the buttons, without these it wont play the whole chime as the diode provides DC power after the button has been released, you must have a diode on each button, if you have lost the diodes then go to Radio Shack and any axial 1 amp diode with a reverse voltage of at least 50 volts should work polarity doesn't really matter as the chime has a full wave bridge rectifier at the front end so the AC from the transformer doest harm it, but to make the chime continue after the button is released you have to have the diode across the button.

If the chime old chime was electronic and you replaced it with a solenoid type then check the buttons for the diodes as the diode will continue to supply a pulse DC that will make a solenoid type chime hum and or stay pulled in so in this case you have to remove the diodes and if there is more then one button make sure you remove the diode at each button.

 

[GoldDigger]

Here's my problem, I replaced a buzzer style door chime with a regular chime because the client hated the sound. Now when the button is pushed the chime sounds and it's followed by a buzz. What's up with this? The transformer is attached to a jbox and the chime and button were wired in phone wire. I have bypassed the switch and still get the same result. Any idea's

I will start by assuming that your "regular chime" is the mechanical solenoid type rather than electronic. If it is electronic, there are some suggestions in other post(s).
What voltage is the transformer?
What voltage and current is the door chime rated for?
And now long is the wire (total length of the two conductors) from transformer to pushbutton and chime?
And most important, does the buzzing stop immediately when you release the push button?

If the resistance of the wire is very low, and the transformer is oversized, the solenoid may get enough current while the button is held in to cause it to buzz.
In some cases mounting the chime with the solenoid in the wrong orientation can also cause a buzzing.
Try reducing the output of the transformer by putting a resistor in series to complete the circuit instead of the pushbutton. (Figure the size of the resistor to drop 6-10 volts at the current draw of the chime solenoid. If that takes the buzz away (and the chime still sounds), you can replace the transformer with one which is lower voltage and/or lower power capacity and therefore higher internal resistance, or you can put a permanent resistor in series at the chime where is it easily accessible and can be removed or changed in value when the chime is replaced.

 

[Jan]

Thanks for the info.

You are correct it is a mechanical chime. The transformer is rated 10v and the chime is rated for 16v. There are 4 wires in the phone wire that was pulled so I could tie 2 of them together to improve the voltage drop. I'll give the resistor a try.

 

[Jan]

I forgot to answer the other questions

length of run 15' at most
Once I release the button the buzzing stops.

 

[kwired]

I forgot to answer the other questions

length of run 15' at most
Once I release the button the buzzing stops.

Like I said before, these solenoid coils are pretty inexpensively made, most I have ever seen are noisy to some extent. The buzzing stops when you release the button because the coil is no longer energized when you release the button.

applying only 10 volts to a 16 volt chime probably doesn't help much, it will try to draw more current (that probably isn't available) to try to pull the plunger of the solenoid.

 

[hurk27]

Like I said before, these solenoid coils are pretty inexpensively made, most I have ever seen are noisy to some extent. The buzzing stops when you release the button because the coil is no longer energized when you release the button.

applying only 10 volts to a 16 volt chime probably doesn't help much, it will try to draw more current (that probably isn't available) to try to pull the plunger of the solenoid.

Exactly, with the new info then we can say the chime is surely undervoltaged, solenoids always require the most current at pull in, after they have pulled in the current drops, so with only applying 10 volts to a 16 volt chime your lucky if you even get it to pull in enough to have the plunger hit the top tone bar, and if it even does it wont stay there causing the plunger to just vibrate I bet your only getting one tone as it mostlikely is not hitting th efirst one but is hitting the second tone bar when it falls back down, put a 16 volt transformer on it and I would bet the problem goes away.

These chimes require the plunger to over travel to strike the tone bar then it falls back down back where the plunger tries to center in the coil until the button is released in which it falls down striking the second tone bar on a two note front door hookup a spring moves it back off the second bar so it can vibrate, if there is not enough voltage and the button is held a little longer then the plunger is not held in the center of the coil causing it to just loosely vibrate, the more closer the coil is to the rated voltage the more the plunger will be held in the middle of the coil where it is design to be held.

Also with the longest run at 15', or 30 feet the 24awg phone wire shouldn't be a problem depending on how far the transformer is from the chime, remember the chime circuit is just one long series circuit starting at the transformer through the button to the chime then back to the transformer, so the length of the run including the transformer will contribute to voltage drop.

Since these chimes operate on very low voltage to start with, voltage drop can be a big problem as 5 volts at 120 might not be a problem but 5 volts at 10 is a 50% voltage drop or half of your supply voltage, and voltage drop is based on current times ohms so it will be the same for a 120 volt circuit as it would for a 10 volt circuit so this is why it is very important to keep it very low when dealing with low voltage circuits, at 10 va we are talking about 1 amp at the most so this is why I said the phone wire shouldn't be a problem at 30' of wire but any longer then you could start seeing problems.

 

[GoldDigger]

Exactly, with the new info then we can say the chime is surely undervoltaged, solenoids always require the most current at pull in, after they have pulled in the current drops, so with only applying 10 volts to a 16 volt chime your lucky if you even get it to pull in enough to have the plunger hit the tone bar, and if it even does it wont stay there causing the plunger to just vibrate, put a 16 volt transformer on it and I would bet the problem goes away.

Actually, you need the plunger to be moved so fast that it overshoots against a spring or gravity to hit the chime bar. If it stays against it instead of bouncing off it will mute the chime. So it shoots out, hits the chime, falls back partway and then, for a two-tone chime, it falls back farther when the button is released and hits the lower chime bar on the rebound, then settles in between them, not touching either.

 

[hurk27]

Actually, you need the plunger to be moved so fast that it overshoots against a spring or gravity to hit the chime bar. If it stays against it instead of bouncing off it will mute the chime. So it shoots out, hits the chime, falls back partway and then, for a two-tone chime, it falls back farther when the button is released and hits the lower chime bar on the rebound, then settles in between them, not touching either.

I should have stated to hold it in the middle of the coil, as the rest I stated in the rest of my post, most of these chimes only has the fall back spring to keep it off the second tone bar, it uses the coil and gravity to keep it off the top tone bar as like you said would stop the bar from oscillating if it stayed against it, if the plunger can't be held in the middle of the coil it tends to vibrate more when the button is held, they are very cheaply made.

If DC could be used then a cap and drain resistor acrossed it could be used as a automatic release if sized corectly so it wouldn't matter if the person held the button or not, it would allow the plunger to shoot up then as the cap drained it would just fall back down as the current to the coil was released as the cap charged, also a stuck button would not burn up the coil as they do now, at one time I had thought about trying this but never did, as the coil should work with DC, but a diode would cut the voltage almost in half so a higher voltage transformer would have to be used, just put the diode and cap at the transformer so it will work for both coils, but if the buttons had lights they might try to charge the cap?

 

[hurk27]

Thanks for the info.

You are correct it is a mechanical chime. The transformer is rated 10v and the chime is rated for 16v. There are 4 wires in the phone wire that was pulled so I could tie 2 of them together to improve the voltage drop. I'll give the resistor a try.

Just a FYI:

Paralleling conductors and AWG doesn't always go hand in hand.

A 24 AWG conductor has about 0.02567 ohms per foot (OPF), paralleling two of them will give you 0.012835 OPF or about the equivalent of a 21 awg better but not by much, paralleling 4 together will give you .0064175 OPF a little less then an 18 awg which is about .006385 OPF which is common size for door bells.

I found this out one time when I was messing around with seeing if two 14 AWG would equal a #10 AWG, and found that it doesn't, it actually comes out slightly less then a #11 AWG

 

[kwired]

Just a FYI:

Paralleling conductors and AWG doesn't always go hand in hand.

A 24 AWG conductor has about 0.02567 ohms per foot (OPF), paralleling two of them will give you 0.012835 OPF or about the equivalent of a 21 awg better but not by much, paralleling 4 together will give you .0064175 OPF a little less then an 18 awg which is about .006385 OPF which is common size for door bells.

I found this out one time when I was messing around with seeing if two 14 AWG would equal a #10 AWG, and found that it doesn't, it actually comes out slightly less then a #11 AWG

Interesting, maybe this has a little to do with why we are not supposed to parallel conductors smaller than 1/0. Somewhere there must be a point where the final parallel resistance is equal or less than a single conductor of similar ampacity.