KEPCO HSF-1U 50W Series - Manual (Page 3)

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KEPCO, INC. " 131-38 SANFORD AVENUE " FLUSHING, NY. 11352 U.S.A. " TEL (718) 461-7000 " FAX (718) 767-1102
http://www.kepcopower.com " email: [email protected]
I/O CONNECTOR: The 24-pin I/O connector (Figure 2) is designed to mate with the corresponding connector in the
RA 19-1U Rack Adapter.
(+) SENSE, (–) SENSE: These lines are provided to compensate for voltage drops in the load connecting wires. The Sense
lines must be connected to their respective (+) and (–) output terminals, either at the load or at the rack adapter (see Rack
Adapter Manual). The connection ensures the most accurate error tracking. Error compensation in the connecting wires is up
to 0.25 Volts per lead for all models.
NOTE:
The Sense lines must be connected for the HSF-1U Power supply to work properly!
OUTPUT (+), OUTPUT (–): HSF-1U power supply d-c output.
CURRENT SHARE BUS (CSB): Connecting the CSB lines of HSF-1U power supplies operating in a parallel configuration
causes output current to be shared equally. (See Rack Adapter Manual for additional information on parallel configurations.).
For current sharing to work properly the outputs of all paralleled units must be within 250 mV (max) of each other and each unit
must be operating at between 10% to 100% of rated output. If current to the load goes below 10% for each unit in current
share mode, all MASTER ON lights may go on (see load effect specifications); this indicates that forced current share is no
longer working, units are simply in current share mode. (If forced current sharing at less than 10% nominal current per supply
is needed, contact Kepco application engineering.) Remote sensing is recommended. For master/slave operation to work
properly each unit should be adjusted to 40 mV (optimum) less than the next paralleled unit (unit 1 is adjusted to VOUT, unit 2
to VOUT – 40mV, and unit 3 to VOUT – 80mV, etc. If the master fails, the unit 2 will become the new master). The 40 mV dif-
ference can be reduced to a minimum of 25 mV as needed to parallel many units and still keep all units within 250 mV of each
other. Adjust the outputs using Vadj trimmer on front panel.
• Optimum difference among output voltages of paralleled units: 40mV
• Maximum difference among output voltages of paralleled units: 250 mV
• Minimum difference among output voltages of paralleled units: 25 mV
ALARM: The Alarm NC (normally closed) - Open on Failure and Alarm NO (normally open) - Close on Failure lines are relay
contacts referenced to Alarm Common. If the unit fails, the path between Alarm NC - Open on Failure and Alarm Common
opens, the path between Alarm NO - Close on Fail and Alarm Common is a short circuit. Figure 3 illustrates typical Close on
Fail and Open on Fail circuits to give a failure indication if any one of a number of power supplies fail.
INPUT POWER: Line (either a-c or d-c source power) , Neutral and Ground (chassis)
FIGURE 2. REAR CONNECTOR PIN ASSIGNMENTS FIGURE 3. TYPICAL ALARM CIRCUIT DIAGRAMS