12
HSF(A) 300W 040215
FIGURE 8. DIP SWITCH SETTINGS FOR USING RESET BUTTON OR REMOTE ON-OFF
3.6
PROTECTION CIRCUITS
The following protection features are implemented in the HSF (A, AM) 300W Series: overvoltage
and overtemperature (PAR. 3.6.1), overcurrent (PAR. 3.6.2), fan failure (PAR. 3.6.3), and under-
voltage (PAR. 3.6.4). The HSF (A, AM) 300W Series provides a configurable visual alarm (see
PAR. 3.7.1) as well as an option to use either relay contacts or logic levels for alarm signals (see
PAR. 3.7.2)
3.6.1 OVERVOLTAGE AND OVERTEMPERATURE PROTECTION
When the output voltage of the HSF (A, AM) 300W Power Supply increases beyond the specified
values (see Table 2), at some point the output is cut OFF and the fan turns OFF. To restart (reset)
the unit, press and release the OUTPUT RESET switch on the front panel or, if the remote on/off
feature is in use (see PAR. 3.5), open connection between the ±RC pins and then reconnect the
pins. The unit may also be restarted by turning the POWER ON/OFF switch to OFF, waiting 40
seconds, then setting the POWER switch to ON.
When internal temperature of the HSF (A, AM) 300W Power Supply increases beyond the allow-
able limit, the output is cut OFF and the fans turn OFF. The restart cycle (Power ON) should not
begin until the temperature returns to within specifications. To restart (reset) the unit, set the
POWER ON/OFF switch to OFF, wait until unit cools, then set the POWER switch to ON. The
power supply cannot be reset using the remote ON-OFF feature unless the power supply remains
shut down for at least 40 seconds.
3.6.2 OVERCURRENT SETTING AND PROTECTION
The Overcurrent Protection (OCP) characteristic is constant current limiting, automatic recovery.
OCP operates when output current exceeds 105% (119% for 24V model) of maximum d-c output
current specification. The output automatically recovers when the overload condition is removed.
CAUTION: Operating the unit under overcurrent or shorted conditions for more than 30
seconds may damage the unit.
The OCP setting is fixed and is not user-adjustable.
3.6.3 FAN FAILURE
A cutoff of the fan supply voltage or a decrease in fan speed causes the output to shut down and the
fans to turn OFF. Fan failure and all the other protection circuit operations produce an alarm (see
PAR. 3.7.2). To restart (reset) the unit, press and release the OUTPUT RESET switch on the front
panel or, if the remote on/off feature is in use (see PAR. 3.5), open the connection between the
±RC pins and then reconnect the pins. The unit may also be restarted by turning the POWER ON/
OFF switch to OFF, waiting 40 seconds, then setting the POWER switch to ON. If fan rotation is
out of specification the power supply will not recover.
3043784
3
3 +RC
+RC 3
3
SW1
4
SW2
4
OFF
ON
OFF
ON
(FACTORY DEFAULT)
USE FRONT PANEL
RESET BUTTON
A
B
(LOGICAL LEVEL OR
MECHANICAL SWITCH)
USE REMOTE ON-OFF
3
3
SW2
SW1
4
4
ON
OFF
OFF
ON
3 +RC
4 -RC & -PF
+RC 3
-RC & -PF 4
TAB
-RC & -PF 4
4 -RC & -PF
!
