simple bell circuit?

[mackeral]

Fault finding on a bell circuit... Three bells are installed on a circuit along with a push and a transformer. When 2 bells are connected the push will ring the connected bells. However when 3 bells are connected they will not ring. I think each bell is rated at 0.5 A. However the transformer is rated at 12V 1A. Is this a straight forward case of not having enough power from the transformer? Also, what about solutions?

A larger transformer with higher amps on the secondary side?
Or a booster, ie. another 12V 1A transformer at the end of the circuit?

cheers guys

 

[plugwash]

if you want them all to ring on the same bellpush then you need to replace the transformer with one large enough to run all of them.

 

[mackeral]

thanks Plug...
an acquaintance suggested a transformer with a higher voltage, but surely a tx with a higher current rating is required?

 

[Killemall]

If you connect the 3 bells in parallel with the supply, a 12 volt transformer with a higher current rating is required.

 

[breezer]

to clarify

you said each bell is 0.5A
transformer is 1A

3 x 0.5 =1.5A

its too much (as has been said)

 

[ban-all-sheds]

an acquaintance suggested a transformer with a higher voltage

Why does this acquaintance want you to damage all 3 of your bells? Have you done something to upset him?

 

[Lectrician]

Volt drop can be a huge issue with bell wire and bells!

Another transformer is needed, but you will probably also need to tackle the problem of volt drop.

I had a similar problem with a bell system in a hotel. Push at reception, 5 bells around the staff areas. DIY-er/manager wired it, and it didn't work! We utilised his cabling and fitted a couple tx's and relays to sort it out.

 

[mackeral]

yes Ban i probably have upset him at some stage...
Anyway, i thought he may have thought of Volt Drop, but the cable is 1.0mm.

Lectrican, whats with the relays?

 

[breezer]

relays are if you will an electrical switch usualy used so that a small voltage can switch a big voltage or current (or both)

They are an electromagnet that operates a mechanical switch

so you could have in lectricians example a small (say 12v) relay operating say 24v bells.

or you could have say a 12v supply operating 12v bells, but by the time the voltage gets to back to the relay it may only be say 10v but just enough to operate the relay, which then operates the bells.

cars have a relay, when you turn the ignition to start, it pulls in a relay, which then operates your starter. the ignition switch can carry say 0.5A but the starter may draw say 30A (which would burn out the switch and its wiring.

 

[ban-all-sheds]

i thought he may have thought of Volt Drop, but the cable is 1.0mm.

14-15m for a 1V drop....

 

[ban-all-sheds]

the starter may draw say 30A (which would burn out the switch and its wiring.

Closer to 300A than 30A, IIRC....

 

[Lectrician]

On the system we altered, we used his setup as it was, but removed the bells and fitted relays in their place. Very low current, minimal volt drop.

At each relay we fitted a new PSU for each bell (just the cheap friedland ones).

Cost more than the hotel had previously wanted to spend, and if designed from start to finish we would have done it very differently, but with cables already in etc etc we made the best of **** shop.