Motorola MTR2000 T5544 Instruction / Field Service Manual page 258

68P81011Y31-O
03/10/06
Fan Control Line
The supply incorporates temperature sense/fan enable circuitry for con-
trolling a 12Vdc fan mounted on the surface of the heatsink assembly. The
power supply circuitry senses the internal temperature of the power sup-
ply. When the internal temperature exceeds +60°C (± 5°C), +12 V is en-
abled at J1–1 to turn on the fan. The +12 V fan supply is derived from the
+14.2 V output. Power to the fan is off when the temperature is below the
set limit. The fan turns for approximately 5 seconds when power is first
applied as a diagnostic indicator that the fan is functional.
Overtemperature Protection
The power supply will turn off all outputs when an operational ambient
temperature of +80°C (±2°C) has been reached with the supply operating
at any input within its operating input voltage range (dc and ac).
DLN6622 – 500W Power Supply Module
5