Magnetic Contacts current draw


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Old 06-29-12, 10:42 AM
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Magnetic Contacts current draw

Hello,

I'm trying to make the Current Draw Worksheet for my system but I get no idea or info about how much power draw each magnetic contact.

I got:

Ademco PAL-T
Ademco 940
Ademco 943

contacts

Another thing I would like to consider to estimate the total current draw from system is that when I sum the total current I should take the alarm value (the most high value) from standby/alarm values ? for example, 6160V Keypad: 60mA/190mA, I use 190mA for the total current?

Thanks
 
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Old 06-29-12, 05:55 PM
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Hardwire contacts are just dumb switches and don't have to be accounted for in the power calculation. The current consumed by hardwire zones is accounted for in the alarm control's base current consumption.

For power consuming devices like the keypads, the standby current is what you add to figure out the proper backup battery size, the alarm current is important for the system total power limits.
 
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Old 07-02-12, 03:02 PM
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Thank you,

Just another thing,

Vista 21ip manual says "600mA maximum total of aux. power plus bell output currents". But it also says "In UL installations, maximum current draw from the aux. output and the alarm output combined must not exceed 600mA".

So I understand that sounder should not be added neither to the total ? I have a 748 siren which is 1200mA, almost I have a 17.2AH battery but I don't know if this is enough for all that power consumption.
 
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Old 07-02-12, 05:09 PM
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No, the sounder counts. The 600 mA limit is to meet UL specifications for power capacity. The actual maximums are the higher number, but relies on the battery to smooth out the alarm power.


In short, the alarm total include all keypads, all motions, and all sounder devices.

Just use the calculation formula in the installer manual.
 
 

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