KEPCO HSF-1U 100W Series - Manual (Page 3)

082306 228-1462 REV 5
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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]
(+) 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 (local) or at the rack adapter
(remote); see the 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!
Ripple and noise at the load may increase if remote error sensing or if long connecting wires are used; this can be
reduced by using twisted and shielded sense and load wires, additional filter capacitors at the load and by proper
grounding at either the load or power supply terminal with just one ground point in the system.
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 V
OUT
, unit 2
to V
OUT
– 40mV, and unit 3 to V
OUT
– 80mV, etc. If the master fails, the unit 2 will become the new master). The 40 mV differ-
ence 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 provide an alarm for a failure of a single unit fail; refer to RA 19-1U manual for complete infor-
mation regarding other configurations. Units are shipped so that the alarm will trip and shutdown will occur upon overvoltage,
open sense line and fan failure (fan failure shutdown can be disabled, see COOLING and Figure 5). The alarm will also trip
upon undervoltage, however shutdown may not occur, depending on the load After shutdown occurs, 60 second delay (mini-
mum) is required before turning the unit on again.
Forced shutdown upon fan failure can be disabled by installing a jumper, Kepco P/N 172-0382 (Digikey P/N A26231-N) as
shown in Figure 5. This allows the unit to continue to operate with the fan inoperative (see Figure 4 for safe operating condi-
tions); the alarm signals noted above will report an alarm condition, and the VDC ON indicator will either light red (fan supply
voltage missing) or flicker between red and green (mechanical failure). With the jumper installed the user is responsible for
either reducing the load to within the specifications given in Figure 4, or shutting down the unit using the alarm signals pro-
vided.
COOLING: Forced convection, ball-bearing fans, life expectancy 50,000+ hours. Natural convection can be used if the load
does not exceed 60% of max. (see Figure 4). Simply disconnect the fan and install jumper J1 (see Figure 5); the alarm signals
described above are disabled and VDC ON lights red; overvoltage and open sense line conditions still force unit shutdown.
Contact Kepco’s Applications Engineering for full-featured natural convection cooled units.
EMI: Designed to meet FCC Class B (100-120V a-c) and VDE 0871 Class B (220-240V a-c).
FIGURE 2. REAR CONNECTOR PIN ASSIGNMENTS FIGURE 3. TYPICAL ALARM CIRCUIT DIAGRAMS