Power Supply; Primary Power Terminals; Primary (Ac) Power Circuit; Installing The Transformer - Bosch D7212G Operation And Installation Manual

4.0

Power Supply

4.1

Primary Power Terminals

4. 1 . 1

Primary (AC) Power Circuit

A 16.5 VAC, 40 VA internally fused transformer (Bosch Security Systems D1640) is the primary power source. The AC power
circuit provides 1.9 A of rectified AC power. The panel reserves 500 mA of this power for internal operations leaving 1.4 A for
powered devices.
Transient suppressors and spark gaps protect the circuit from power surges. This protection relies on the ground connection
at Terminal 10. Make sure to connect Terminal 10 to a proper ground. See Section 3.5 Connecting Earth Ground on page 22.
AC Power Failure
The system indicates an AC power failure when the power at Terminals 1 and 2 is missing. The AC Fail Time program item
sets the number of minutes or seconds that AC must be missing before the panel acknowledges the failure and the number
of minutes or seconds after the power returns before the panel acknowledges the restoral of power. See the D7212G Program
Entry Guide (P/N: 4998138538) for additional information regarding AC Fail Time.
4. 1 .2

Installing the Transformer

Do not short the terminals of the transformer: Shorting the terminals opens the internal fuse causing permanent failure.
Connect the transformer to Terminals 1 and 2 of the panel before plugging it into the power source.
Use 18 AWG (minimum) wire to connect the transformer to the panel. Wire length should be kept as short as possible.
Maximum length is 50 ft. (15 m).
AC wiring can induce both noise and low level voltage into adjacent wiring. Route phone and sensor loop wiring away from
any AC conductors, including the transformer wire. Route data wiring away from AC and phone wiring.
Connect the battery and then plug in the transformer: Bosch Security Systems recommends that the battery always be
connected first and then the transformer be plugged in. See Section 4.2.2 Installing the Battery on page 26.
Only plug the transformer into an unswitched, 120 VAC, 60 Hz power outlet. Secure the transformer to the outlet with the
screw provided.
D8004 Transformer Enclosure required for fire systems: Use the D8004 Transformer Enclosure for the D1640 transformer in
fire and combined fire/burglary applications. Check with the Authority Having Jurisdiction (AHJ) on mounting
transformers on specific circuits.
4.2

Secondary Power Terminals

4.2. 1

Secondary (DC) Power

A 12 V, 7 Ah (up to 14 Ah) sealed lead-acid rechargeable battery (D126) supplies secondary power for auxiliary and alarm
outputs, and powers the system during interruptions in primary (AC) power.
Lead Acid Batteries ONLY: The charging circuit is calibrated for lead-acid batteries. Do not use gel-cell or nicad batteries.
Extra Batteries Increase Back-up Time: To increase battery back-up time, connect a second 12 V, 7 Ah battery in parallel to
the first battery to form a 12 V, 14 Ah battery. Use a D122 Dual Battery Harness to ensure proper and safe connection.
D1218 Battery
The D1218 is a 12 V, 17.2 or 18 Ah battery and can be used in applications requiring extended battery standby time. Up to
two D1218 batteries may be connected when used with a D122 Dual Battery Harness. Do not use any additional batteries
when using a D1218 battery.
© 2003 Bosch Security Systems
D7212G Operation and Installation Guide
Page 25
D7212G
Power Supply
4998138544C