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ALARM CIRCUIT. The HSF-1UR includes an isolated
internal relay offering normally closed and normally open
contacts referenced to an isolated common. These con-
tacts may be used to configure "close on failure" or "open
on failure" alarm circuits. (Refer to the RA 19-1U Manual
for alarm configurations for multiple HSF-1UR power sup-
plies.)
KEYING. Keying of the HSF-1UR is established at the
factory (see Figure 3). The output voltage determines
which key pins are installed. When the proper holes in the
rack adapter are blocked by keying screws installed by the
user, only a power supply of the correct voltage can be
inserted in the rack adapter slot. (Refer to the RA 19-1U
Manual for rack adapter keying instructions.)
FIGURE 3. REAR CONNECTOR PIN ASSIGNMENTS
CONNECTIONS: The 24-pin I/O connector (Figure 2)
mates with the corresponding connector in the RA 19-1U
Rack Adapter. All external connections are made at the
rack adapter (see Rack Adapter Manual).
These lines are provided to com-
(+) SENSE, (–) SENSE:
pensate 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.
The Sense lines must be connected for the
HSF-1UR Power supply to work properly!
Compensation per lead = (min. overvoltage - max.adjust-
ment range)/2); refer to Table 1. Compensation for 3.3V
Model is 0.1V per lead. Higher compensation values are
KEPCO, INC. 131-38 SANFORD AVENUE FLUSHING, NY. 11355 U.S.A. TEL (718) 461-7000 FAX (718) 767-1102
021219
NOTE:
http://www.kepcopower.com email: hq@kepcopower.com
possible if output voltage is decreased below the maximum
adjustment range shown in Table 1. Load wire length
should not be more than 16.4ft. (5m). Transient recovery
specs may not be met when remote sensing is used. To
prevent oscillations and premature tripping of overvoltage
protection, install one electrolytic (not tantalum) capacitor
(470mF min) between +S and +V and one between ±S ter-
minals.
OUTPUT (+), OUTPUT (–):
put.
Line (either a-c or d-c source power), Neu-
INPUT POWER:
tral and Ground (chassis)
CURRENT SHARE BUS (CSB):
els.) Connecting the CSB lines of HSF-1UR power supplies
operating in a parallel configuration causes output current
to be shared equally. (See Rack Adapter Manual for addi-
tional 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 out-
put. 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 appli-
cation 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 paral-
leled unit (unit 1 is adjusted to VOUT, unit 2 to VOUT –
40mV, and unit 3 to VOUT – 80mV, etc. If the master fails,
unit 2 will become the new master). The 40 mV difference
can be reduced to a minimum of 25 mV as needed to paral-
lel 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 par-
alleled units: 40mV
• Maximum difference among output voltages of
paralleled units: 250 mV
• Minimum difference among output voltages of par-
alleled units: 25 mV
The Alarm NC (normally closed) - Open on Fail-
ALARM:
ure 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 4 illus-
trates typical Close on Fail and Open on Fail circuits to give
a failure indication if any one of a number of power supplies
fail; refer to RA 19-1U manual for complete information
regarding other configurations.
228-1621 REV 8
HSF-1UR power supply d-c out-
(Not available on 3.3V mod-
3
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