Power supplies for Voice alarm equipment
The PS-RACK series of battery chargers (24 Vdc) are intended for a Voice Alarm System. The battery chargers are microprocessor based devices that have been designed to charge lead-acid batteries (back-up batteries connected to the Voice Alarm System) and, simultaneously, to provide power to auxiliary devices such as the DIVA8 and IDA8 system controllers
The PS-RACK battery chargers, which are fully compliant with EN54-4, offers a maximum charge current of 6 or 12 A. The battery charger is two rack units high, and has to be installed in a 19” rack. Maximum battery capacity: 225 AH.
To find the right power back-up system for your needs, you will need to determine the exact conditions under which you will be utilizing a back-up system. Determining the amount of battery back-up you need for a system is not as simple as some other applications. Public address systems do not draw a constant current. The standard defines a standby time and an evacuation time. In this case, it is important to pick a battery back-up that can supply the minimum amount of power needed for a set amount of time. ATEIS can provide you with a battery calculator program to determine the exact capacity.
1. Determine the standby current of the system. This information is available in the voice alarm system manual.
2. Multiply the standby current by the standby time that the local standards call for. Typically this is 24 hours.
3. Compare this value to the 24 hour discharge capacity of the battery.
4. Determine the evacuation current of the system. This information is available in the voice alarm system manual.
5. Multiply the evacuation current by the time that the local standards call for. Typically this is one hour or 30 minutes.
6. Compare this value to the 30 minute or 60 minute hour discharge capacity of the battery.