American Power Conversion MX28B200 user manual DC Distribution, Battery Management

System Status and Alarm Reporting

The PSCU will monitor system voltage using a high accuracy digital voltmeter attached to the system bus. The PSCU will monitor system temperature using a temperature IC mounted in the PSCU. The PSCU will monitor system current by summing the current reported by individual rectifiers. The PSCU will report a number of system alarms including system high/low voltage and high/low temperature. Refer to Section 4.6 for PSCU control functions.

4.4. DC Distribution

Distribution is included for up to 24 plug-in circuit breakers. These circuit breakers can be 1 to 100 amps, with 60-100 amp breakers requiring two positions and a circuit breaker adapter kit. When a circuit breaker trips, a normally open switch closes and a CB alarm is reported by the PSCU. To disconnect a load attached to a circuit breaker, move the lever to the down “OFF” position.

NOTE: Circuit breaker alarm contacts close when the circuit breaker is tripped but not when it is turned OFF.

Eight GMT fused outputs are also available as an option. This option uses one of the 24 available circuit breaker positions. When a GMT fuse trips, an alarm spring is revealed that visually indicates the fuse is blown. The alarm spring also makes contact with a third contact on the fuse holder, which connects the –48 VDC bus voltage to the GMT fuse alarm input in the PSCU. Upon measuring voltage on this alarm circuit, the PSCU will report a GMT fuse alarm. To disconnect a load attached to a GMT fuse, pull the fuse out of the fuse socket.

NOTE: GMT fuse alarm contacts complete the alarm circuit when the fuse is tripped but not when the fuse is removed.

4.5. Battery Management

Battery Charging and Protection

Battery charging and protection are integrated into the MX28B DC power system to support the primary function of providing power to the load. Accurate measurement of battery parameters like voltage, current and temperature are used to maintain and protect the batteries attached to the power plant.

Charging the battery at the correct rate reduces battery heating, increases the charge returned to the battery and prevents excess hydrogen generation or, in the case of VRLA

MX28B200/400 –48 VDC User’s Manual (990-9133) Page 25