What does SCB mean. Amature

SCB ---- Self Contained Bell

Thank you Alarmguard for prompt reply.

and before you ask SAB is self activating bell

basically the difference is that an scb operates via its own battery, and an sab draws its current from the panel

this is becasue most scb sounders draw a LOT of current, which the panel can not supply, so when not sounding the scb batteries are charged up by the panel.

so if you have an scb that is quiet, chances are its batteries are or very near flat.

With an sab the battery is there so if some one removes it from its fixings it operates

And SAS is self actuating sounder, same as the sab but has a sounder instead of a bell (dont see many bells nowadays)

I've always wondered what differentited SCB's from SAB's.

How can you tell whether you've got an SCB or an SAB bell box?

I know some of the newer types have SAB/SCB links, but what about the older fixed types, how do you tell?

And while we're on the subject, I take SAB's are the preferred type nowadays?

If you cant find anything at all on an old module to say if its SAB or SCB then the current reading will show the difference - meter between bell + on panel and supply + cable then move trigger wire to hold neg.

generally an scb has a big battery, this is because the sounder draws a lot of current, that the panel can not supply.

Generally speaking SCBs are held off by the panel, using a voltage from the sounder output. mostly negative but can be positive. Remove wire from sounder output if it starts making noise then its SCB if you have to apply a voltage to make noise then its SAB. SCBs are considered a more secure device, as blown fuses on sounder ringing side will activate sounder rather than kill device, but as SCB is totally dependant on its own battery it does mean that service engineers have to get ladders off car and check them.

Regards

Adrian

PS, One assumes that the service engineer has ladders and knows what they for.

PPS, It is so hard writing this and not refering to outside SOUNDER as BELL, Havent fitted a bell for 10 years but we still call it that.

PPPS, Did my PS sound condescending about service engineers, of course they know what ladders are for, they sit in the cafe and and talk about them all day long.