adding additional chimes to a wired door bell system?

[HappyHippyDad]

Evening all

I have recently fitted a door bell for a customer. He would now like additional chimes in the kitchen and upstairs. It is a wired system as he specifically said he did not want anything with batteries.

At present it just has the normal (8v) bell transformer right next to the chime. one additional chime will be a run of about 8m's and the other perhaps 10m's.

Transformers are not my strong point and I am unsure how to determine which one to change the existing one for so that it can deal with all 3 chimes?

Any advice chaps?

 

[telectrix]

measure the current drawn by 1 chime . then make sure the transformer is rated at least 3 x that current.

 

[HappyHippyDad]

Thanks Tel..

The chime is right next to the transformer so very little resistance. When I add the other chimes they will be much, much further plus the bell cable has small CSA so wouldn't the resistance be much greater and have a bearing on transformer needed?

I'm starting to get that 'embarrassed' tingle. I know I'm going to say something silly in a minuite!

 

[Octopus]

Who is the manufacturer? Call their technical line? Longer runs do need tranny's

 

[Buckfast]

Would likely use a larger voltage and VA rated transformer. Run each supply to each bell seperately and supply by a variable resistor with centre contact(Slider supplying bell) This can then be adjusted to give correct voltage/current to make all bells ring at same volume and also will allow for voltage drop. Easy enough to make up power supply and variable resistors on vero board.

 

[HappyHippyDad]

Who is the manufacturer? Call their technical line? Longer runs do need tranny's

That is a very good suggestion! I always think they are not going to be very helpful but was proved very wrong when I rang 'Drayton' the other day.

Thankyou Murdoch.

Sometimes though I think I put these questions up at around this time as its nice to have a bit of a chat about them..

 

[Octopus]

That is a very good suggestion! I always think they are not going to be very helpful but was proved very wrong when I rang 'Drayton' the other day.

Thankyou Murdoch.

Sometimes though I think I put these questions up at around this time as its nice to have a bit of a chat about them..

I had reason to call Drayton a while back and they were great!

 

[Knobhead]

 

[ipf]

For Christ's sake DING,DING,DONG!!!!!!

 

[Knobhead]

I did that drawing years ago for the same question on here. Took a while to find it, couldn't resist putting it up.

Sorry HHD

 

[Knobhead]

If any of you remember a part of EF got hijacked by a site in Nigeria (I think) that drawing was in the bits that got diverted. God knows what they thought of British electricians!

 

[tazz]

A VR would burn up in seconds put into the circuit.....Telectrix has given you the answer in post 2

 

[Buckfast]

A VR would burn up in seconds put into the circuit.....Telectrix has given you the answer in post 2

Could i ask why the VR would burn out in seconds. The correct wattage and resistance of VR would not burn in any way. This could easily be calculated using ohms law for correct value. Have used this method several times over the years but must admit since the advent of radio chimes not for a while. VR is just acting as potential divider. Could be wired in parrallel or series.

 

[tazz]

Could i ask why the VR would burn out in seconds. The correct wattage and resistance of VR would not burn in any way. This could easily be calculated using ohms law for correct value. Have used this method several times over the years but must admit since the advent of radio chimes not for a while. VR is just acting as potential divider. Could be wired in parrallel or series.

Try it and see, you are working 8v ac here, and would need a decent 1watt wire wound.....correct method would be to use a voltage reg, and use your vr on the ref leg...Lm317 for instance, you could rectify and have a nice 3-8v dc supply

 

[Buckfast]

Try it and see, you are working 8v ac here, and would need a decent 1watt wire wound.....correct method would be to use a voltage reg, and use your vr on the ref leg...Lm317 for instance, you could rectify and have a nice 3-8v dc supply

Do not wish to go in to long winded debate over doorbells when op has already said he will contact manufacturer. I do not need to try it, as previous post, i already have many times. As i have run a very successfull electrical and electronic repair company for over 31 years, i am more than aware of voltage regulation and stabalization both using regulators and zener diodes, switch mode psu's. The op was not asking for DC and required more than 8V as he already had this. Also when rectified and smoothed you would in fact end up with a DC voltage of 11.31 volts prior to regulation if needed, not 3-8 volts I am quite happy for you to have a view but as previous post this method will and does work. It is also cheap and easy to do. (We are talking a doorbell ?).