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4.4.4 Automatic Crossover
If the power supply operates in Constant voltage mode while the load current is increased to greater
than the current limit setting, the power supply will automatically switch to Constant current mode. If the
load is decreased to less than the current limit setting, the power supply will automatically switch back
to Constant voltage mode.
4.4.5 Over Voltage Protection (OVP)
1.The OVP circuit monitors the voltage at the power supply sensing points thus guaranteeing the
protection level at the load. Upon detection of Over Voltage condition, the power supply will shut
down. To resume operation, the power switch should be turned off for approx. 30sec. Prior to turn-on,
check carefully that the sense wires are connected correctly and secured.
2. OVP setting values are limited at the minimum and maximum levels. At minimum level, the OVP level
is limited by the Output Voltage setting, therefore the OVP level cannot be adjusted below the
Output Voltage. At maximum level, the OVP level is limited to the values shown in Table 4-1.
MODEL (by output voltage)
Maximum OVP
Table 4-1: Maximum OVP setting levels.
3.For over voltage protection adjustment, press OVP/UVP consecutively, until the OVP LED
illuminates and the VOLTS display shows OUP. The AMPS display will show the over voltage
protection setting value. Rotate the ADJUST knob to set the over voltage protection level. Approx.
3sec after the adjustment, the display returns to show the actual voltage and current.
4. In order to see the value of the OVP, press OVP/UVP pushbutton, so that the OVP LED illuminates.
At this time the display will show the OVP set value for approx. 3sec.
5. The minimum over voltage level is approx. 105% of the output voltage set value. Attempting to
adjust the over voltage protection below this value will result in no response to the adjustment
attempt.
6. In case the OVP is triggered, the front panel control is disabled unitl the AC input is recycled by
turning the AC ON/OFF switch to OFF and after approx. 30 sec. to ON.
4.4.6 Under Voltage Protection (UVP)
1.The UVP prevents adjustment of the output voltage below a certain limit. The combination of UVP
and OVP functions allows the user to create a protection window for sensitive loads circuitry.
2. For under voltage protection adjustment, press OVP/UVP consecutively until the UVP LED
illuminates and the VOLTS display shows UUP. The AMPS display will show the under voltage
protection setting value. Rotate the ADJUST knob to set the under voltage protection level.
3. In order to see the set value of the UVP, press OVP/UVP pushbutton, so that the UVP LED
illuminates. At this time the display will show the UVP set value for approx. 3sec.
4. The maximum under voltage level is approx. 95% of the output voltage set value. An attempt to
adjust the under voltage protection above this value will result in no response to the adjustment
attempt.
5.The under voltage protection is a software protection only.
6V
20V
10V
7.5V
24V
13V
36V
60V
80V
40V
66V
88V
120V
132V
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