Manual Part 6

DC /DC Converter
P009809B
Input +24 V Output -48 V DC
Output -48 V DC
Input ALARM
Input Stop
Output Alarm
Control Circuit
Figure 1 DC/DC Converter Block Diagram
The unit is a switched converter that converts +24 V DC battery voltage to
regula ted -48 V DC. The converter can be connected in paralle l with oth er
converters to op erate continuo usly in current limitation mode.
The current limitation is set to 100 – 115% of the rated curren t (4.0 A), above
which the output voltage drops. The output current increases when the voltage
drops, enabling the converter to be loaded with other DC/DC converters, which
have an input power limited to approximately 150 W.
The overvoltage protector shuts do wn the switching when the output voltage
reaches -58 V. T he DC/DC converter reconnects after approxima tely 10
seconds when the output voltag e decreas es to nominal level. If this occurs
five times, the con verter is shut down and blocked. To restart the converter,
the input volt age supply must be disconnected and then reconnected after
approximately 10 seco nds.
The undervol ta ge protector monitors the input vol ta ge and blocks the conv er te r
at a n input voltage of 1 8.0 ±0.5 V. The converter starts automatically when the
input voltage exceeds the start le vel, 20.0 ±0.5 V.
The conv erter can be stopped remote ly by connecting a +5.0 V signal to the
‘‘Stop’’ pin. Normally this pin is left unc onnected.
A green indicat or on the front indicates th at an input voltage, which has
reached starting level, is present in the conversion stage. A red indicator on the
front is active when the output voltage is out of range due to either overload,
overvoltage, or failure.
5 Interf aces
This secti on describes the interfaces of the DC /DC converter.
4 (6)
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N/LZT 720 0301 Uen R3A