Door bell question

S

Steve B 13 years ago

I went to a yard sale the other day. In a box was a transformer, 10v. There was a bell that had a little vibrating clapper that worked off an electromagnetic coil, with a little breaker set to cause it to repeat itself at a rapid rate.

There was also a "ding dong" chime unit in there, which I didn't want. I wanted the bell for my shop for people to ring for service.

I now realize that the transformer probably went to the chime, as it has chime written on it. The transformer has black/white/green lines and comes off 110v, then has two screws for leads to the ringer.

I hooked it up direct to 12 v. dc, and it worked vigorously. I don't think the electromagnets would be used in an ac setup. The bell has one hot lead to the electromagnets, which are two coils with one wire running through both of them, and then a green ground screw to the base.

My question is: What is the best way to determine how much voltage the bell is rated for. No writing on the bell. If I had some fancy power source that had voltage ranges, I could do this by just setting it. Would a 9v. square smoke detector type battery have enough amperage to be a conclusive test? I guess I could look through the hundreds of little power suppliers I have and find a 9v dc unit, and cannibalize it.

Just don't want to fry if in the meantime. So, trying to find a safe way to determine just what it is. Plus, it cost me a buck, and I don't want to blow that. It is vintage, looks like the sixties, and looks like it has never been used.

Steve

Vote

H

hrhofmann 13 years ago

Steve,

You can operate the clanging bell off of AC or DC. Probably down to 6 V or maybe less. What you might have to do is adjust it to work on a lower voltage by adjusting the points that open when the coil is energized, The lower voltage will mean the armature will not move as far and so it may not open the contacts to break the circuit. It should be obvious if you study the operation closely. If you only will be operating the clanging bell for short periods of time, like when a customer comes into your shop and you are in a back room, a 9V battery should be ok. Can't hurt to try one and see what happens. Otherwise, a wall-wart that outputs either AC or DC should be ok. To save power, you could have the custoner push a button that closes the primary 120V AC power to the wall-wart. On the other hand, most pushbuttons are not rated for 120 V so if you do put the button in the primary, check it is rated for 120V. Let us know what finally happens.

Vote

G

gregz 13 years ago

Changing voltages Is one way to determine minimum voltage needed. Then, go up a bit.

Greg

Vote

C

clare 13 years ago

MOST of those bells ran on either 1.5 or 3 volts, back in the day. A large "ignition cell" about 2 or 3 inches in diameter and mabee 7 inches high with binder post connectors was the common power source - and generally lasted a year or more. Some used 2 in series. Then some ran on 6 volts - using a "lantern battery". I'd test it with a C or D cell first and if it is too anemic try two.

Vote

C

clare 13 years ago

DO NOT use a 120 volt pushbutton. Dangerous and un-neccesary.

Vote

C

clare 13 years ago

True on a gong, but not on a buzzer/clanger/vibrating bell

Vote

H

harry 13 years ago

They are only operated for a couple of seconds. Not long enough to cause damage if the voltage is slightly over.

Vote

T

Tomsic 13 years ago

The doorbells that I've seen in old buildings, including the clapper type, typically operate off of a 12 volt ac supply i.e. a "doorbell transformer". Ringing the bell for a second or two isn't going to overheat the coil. What gets damaged if the voltage is wrong are the breaker contacts. Take a look at those while the bell is ringing. A little sparking is OK; but a burning smell or bit of smoke when the bell is ringing indicates damage.

Tomsic

Vote

Door bell question

Join the Discussion

Didn't find your answer?