Fans; Power Supply Unit (Psu) Indicators, Switches, And Connectors - Motorola DIMETRA MTS 4 Installation, Configuration, And Service Manual

Applicant: Motorola Solutions
298 | Power Supply Unit
Charge voltage decreases with increasing battery temperature with the ratio of -72mV/C, starting with 56.88VDC
+/-1% at -10 °C and ending with 52.56 VDC +/-1% at +50 °C
The PSU charges the backup batteries on the following conditions (DC In Status LED is flashing fast (0.5 s) red-
green):
• Temperature range*:-10 °C to +50 °C
• Battery Low Voltage start up:40V -5%/+1%
• Battery Low Voltage Warning:43V ±2%
The PSU stops charging the backup battery on the following conditions:
• Internal PSU temperature:> 100 °C
• Battery Temperature*: -12.5 °C
• Battery Temperature*:> 53 °C
*When a temperature sensor is connected to the battery and PSU. If the battery sensor is not connected the battery
will be charged with 54.24 ±1%VDC as if the battery temperature was 25 °C. The battery temperature monitored
through CAN Bus will show 100 °C.

Fans

The PSU supplies fans, which are located in the fan trays under the module cage. For more information on fans, see
Cooling Fans on page
1 A for each fan.
Three fan output connectors supply three fan trays with two fans connected in parallel in each fan tray.
Fan supply output voltage can be automatically regulated as a function of PSU internal (ambient) temperature and its
output power. Fan supply output voltage can also be controlled by the CAN Bus in 7 steps from 24V to 12V. The
highest value wins – automatic control versus CAN control.
At an ambient temperature below -10 °C the fans are stopped and restarted again at -8 °C. The fan supply ramps up to
24V output for a few seconds in all start up situations.

Power Supply Unit (PSU) Indicators, Switches, and Connectors

The following figure shows the positions of indicators, switches and connectors on the PSU front panel.
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305. The PSU DC output voltage dedicated for fans is 12 to 24VDC and the output current is
Equipment Type: ABZ89FC5827 / 109AB-5827
Exhibit D2