Positron 7885-2, Описание и установка

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Standalone Power Supply Unit 120 V dc to -24 V dc 5
7885-2 & 7885-3
The following is a description of the elements of the Standalone Power Supply
Unit block diagram.
Input Breaker
The Input Breaker circuit on the right side panel of the 7885-2 is a 1 A circuit
breaker providing standard input protection.
Transformer
The Transformer provides 1500 V isolation while stepping down the voltage for
the regulator.
Rectifier
The Rectifier fully rectifies the AC input voltage.
Filter
The Filter is made of a big electrolytic capacitor that filters the 60 Hz input to
provide a DC voltage to the regulator.
Voltage Regulator
The Voltage Regulator takes the filtered voltage from the input and gives out 48
V dc to the output.
Current Limit
The Current Limit circuit is a linear current limit circuit that drops the output
voltage as the current increases past the limit value.
Output Breaker
The Output Breaker circuit on the front panel is rated at 2 A and provides short
circuit protection to the power supply.
Batteries
Each Battery is a 12 V, maintenance-free Dryfit type. They require no more than
24 hours to reach full charge, and can hold 5.7 ampere-hours of charge. This
corresponds to 570 mA over a 10-hour discharge period. Since the four batteries
are connected in series, this current is available at 48 V dc.
Under Voltage Detection
The Under Voltage Detection circuit monitors the batteries and lights a LED
when the voltage approaches the minimum specified voltage of the power supply.