Two 16/40 va transformers burned out on the same alarm panel circuit in the same installation, days apart. New and different system installed resulted in a third 16/40 transformer producing a noticeable hum. New system did not produce the hum when later connected to power in a different home. Any ideas??

 

Originally posted by J Newburgh@Mar 12 2006, 08:17 PM
Two 16/40 va transformers burned out on the same alarm panel circuit in the same installation, days apart. New and different system installed resulted in a third 16/40 transformer producing a noticeable hum. New system did not produce the hum when later connected to power in a different home. Any ideas??

[post=14911]Quoted post[/post]​

What is '16/40'? Did you check the incomong mains supply voltage?

 

Originally posted by pebe@Mar 12 2006, 04:59 PM
What is '16/40'? Did you check the incomong mains supply voltage?

[post=14912]Quoted post[/post]​

16/40 va is a 16 volt ac step down transformer supplying 40 volt amps of power, used mainly in intruison alarm system which operate on 12 volts, converted in the alarm panel to dc voltage.

I'll check the house power next time on site
thanks

 

Crook back up battery, requiring excessive charging..... crook 13.8 volt regulator..... excessive current draw of the panel electronics.... excessive draw of a sensor.... excessive draw on other accessory....ie outside sounder, autodialler etc etc.
The only way to tell is to check each. Measure the voltage on the battery.... should be 13.8.
Remove the main DC fuse and battery. Put a few amps load across the battery and check the voltage doesn't drop below 12 volts.
Hook a current meter in the fuses place and check current draw. If more than a couple of amps, then disconnect sensors, aux devices etc until you find the culprit.