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HSF 300W 042315
3.9
LOCAL/REMOTE SENSING
HSF 300W Power Supplies allow remote error sensing which can compensate up to 0.4 Volts per
load wire. Local/Remote error sensing is configured by means of separate DIP switches mounted
on the RA 19-4C Rack Adapter (see RA 19-4C Rack Adapter Operator Manual). Either local or
remote sensing MUST be used, otherwise the units will not operate.
3.10
RETAINING LATCHES
HSF 300W series power supplies are provided with (2) retention latches located at each side of
the bottom edge of the front panel (see Figure 5). These latches work in conjunction with the RA
19-4C rack adapters to prevent unauthorized or inadvertent module extraction from an operating
power system. The latch is engaged by loosening the cap-head screw approximately 1/2 turn
CCW (use 5/32” hex key) and sliding the latch down to the bottom of the slot, then retightening the
cap-head screw CW until snug. DO NOT OVERTIGHTEN! To release, follow the same procedure,
except lift the latch to the top of the slot. Be sure to move the latch completely up or down to
ensure full engagement and disengagement of the latching mechanism. When the HSF power
supply is not installed in its plug-in rack adapter, it is recommended that the latch be secured in
the open (up) position to prevent damage.
NOTE: Retaining latches must
not
be used to secure the HSF power supply in the rack
adapter for shipping purposes.
4.
LOAD CONNECTION
Connect the load to (+) and (–) terminals at the rear panel of the Rack Adapter (see RA 19-4C
Instruction Manual for details).
5.
CONNECTING MULTIPLE POWER SUPPLIES
All connections to multiple HSF power supplies must be made via the I/O mating connectors at
rear of the Rack Adapter or by the Rack Adapter DIP switches. These connections, including the
configuration of the two internal HSF DIP switches, are described in the Rack Adapter Instruction
manual, and include:
•
Using one power supply to control the output of multiple supplies.
•
Using parallel master/slave configurations (for increased current or redundancy) where
the user either predetermines the master or allows the load to determine which is the
master. These configurations also cover the use of the Current Balancing feature of the
HSF power supply.
•
Using series configurations (for increased voltage).
•
Using open-on-fail or close-on-fail alarm schemes with multiple power supplies.
NOTE: If parallel-connected units are controlled individually, either a minimum load or voltage
set restrictions are required to avoid slave “idle” or slave “oscillating output” conditions
(When the slave is idle, the output is off, no lights are lit, and the alarm is set.) If the
minimum load is maintained, voltage set restrictions are not required.
Minimum Load:
The minimum load (Amperes) = N x (I/10) where N = the number of
units in parallel, I = Nominal current rating of individual power supply (Amperes). For
applications requiring no load or lower than minimum load conditions refer to the Volt-
age Set Restrictions specified below. Load effect specifications will not be met when
units are operated in redundant mode with load less than 10% per unit.
Voltage Set Restrictions:
To avoid slave
“
idle
”
all parallel-connected units’ output
voltage must be set within 1% or 200mV of each other (whichever is lower) and be at
least 80% of their nominal (rated) output voltage (90% for 48V model).
