Why 24Vac in building automation??

[cyberblak]

Hi,

Anyone knows why they building automation devices are 24Vac powered? It seems to me that 12Vdc, per example, would be far more practical (no need for rectification and regulation from a high voltage on the device end).

Any idea?

Thanks,

cyberblak

 

[PaulHolland]

Flexibility, AC you can transform easy to other voltage levels, up/down etc.. not everything needs DC. relay, valves etc..

Paul.

 

[cyberblak]

But, still, you need to rectify and step-down that voltage into each device... Doesn't this add up to the costs?

 

[IanP]

This voltage level seems to be chosen for safety reasons ..
According to some publications 24Vac and 48Vdc are recognized as the maximum safety voltages that are not hazardous to humans ..

Regards,
IanP

 

[funster]

using 24V AC is for flexibility and safety.

AC voltage can be converted into any other voltage easily,

but DC convertion require complex circuit.

best regards

Hi,

Anyone knows why they building automation devices are 24Vac powered? It seems to me that 12Vdc, per example, would be far more practical (no need for rectification and regulation from a high voltage on the device end).

Any idea?

Thanks,

cyberblak