HSF 300W 042315
9
“high” and 0.0 to 0.4V “low”), or a contact closure. When the ±RC pins are open, using either a
mechanical switch or a high level logic signal, the HSF 300W output is cut OFF. When the ±RC
pins are shorted, the output returns to within specifications. At low level logic, the maximum
source current is 1.6mA and at high level the sink current is 1.0mA. Positions 3 and 4 of both DIP
switches must be restored to the factory default setting (Figure 8A) if remote ON-OFF is not used.
The ±RC pins are isolated from DC output pins and a-c input terminals.
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 300W Series: overvoltage and
overtemperature (PAR. 3.6.1), overcurrent (PAR. 3.6.2), fan failure (PAR. 3.6.3), and undervolt-
age (PAR. 3.6.4). The HSF 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 300W Power Supply increases beyond the specified values
(see Table 2), 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 the internal temperature of the HSF 300W Power Supply increases beyond allowable 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 output characteristic of the power supply is a square type, and the unit is set to produce an
alarm (see PAR. 3.7.2) and shut down if output current exceeds specifications (see Table 2) for
more than 30 seconds. After the cause of overcurrent is removed, the power supply output is auto-
matically restored.and shut down if output current exceeds specifications (see Table 2) for more
than 30 seconds. Once unit shuts down, to recover either: a) press and release the front panel
OUTPUT RESET switch, or b) open and close connection across ±RC terminals, or c) remove a-c
input power (set POWER switch to OFF), wait 40 seconds, then restore a-c input power.
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/
3042877
3
3 +RC
+RC 3
3
SW1
-RC 4
4
SW2
4
4 -RC
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
+RC 3
-RC 4
TAB
