Dräger Fabius 4116029 Technical & Service Manual page 52

Function Description
10.1 Power Supply Unit
The power supply unit consists of the Power Supply PCB, the mains supply
receptacle, the ON/OFF switch, the fuses, the mains filter, and the mains transformer.
The power supply unit powers Fabius with the following voltages:
− +24 VDC
− +5 VDC
10.1.1 Power Supply PCB
The Power Supply PCB uses the voltage regulator L4960 to generate the +5 V
operating voltage.
Two voltage regulators LT1074 connected in parallel generate the supply voltage
(28 V) and the rechargeable battery charging voltage.
The resistor S1 (the conductor is designed as sense resistor) is used to measure the
charging current of the rechargeable battery. An integrated circuit transmits the signal
to the microcontroller.
The signals A and B are fed back to the 24 V voltage regulators and function as
charging current limitation.
The Power Supply PCB monitors the rechargeable battery voltage, generates the
battery symbol control on the display and the power failure alarm.
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