2.3 Overcurrent Protection
¡
An overcurrent protection circuit is built-in and activated at 105%
or more of the rated current. A unit automatically recovers when a
faulty condition is removed.
Please do not use a unit in short circuit and/or under an overcur-
rent condition.
¡
Output voltage shuts down when the output voltage continuously
drops due to overcurrent protection.
¡
Output voltage recovers from overcurrent protection by shutting
down the input voltage and waiting more than 10 seconds then
turning on AC input again, or turning off the output voltage by re-
mote control.
2.4 Overvoltage Protection
¡
When output voltage is increased to the overvoltage protection
value, output voltage is shut down.
¡
Output voltage recovers from overvoltage protection by shutting
down the input voltage and waiting more than 10 seconds then
turning on AC input again, or turning off the output voltage by re-
mote control.
Note :
¡
Please avoid applying a voltage exceeding the rated voltage to an
output terminal. Doing so may cause a power supply to malfunc-
tion or fail. If you cannot avoid doing so, for example, if you need
to operate a motor, etc., please install an external diode on the
output terminal to protect the unit.
2.5 Thermal Protection
¡
A thermal protection circuit is built-in.
The thermal protection circuit may be activated under following
conditions and shut down the output.
1
When a current and a temperature continue to exceed the val-
ues determined by the derating curve.
2
When a fan stops or air flow weakens by intake port or exhaust
port is blocked.
¡
Output voltage recovers from thermal protection by shutting down
the input voltage and cooling down the inside of power supply ad-
equately then turning on AC input again, or turning off the output
voltage by remote control and cooling down the inside of power
supply adequately then turning on the output voltage by remote
control.
2.6 Output Voltage Adjustment Range
¡
To increase an output voltage, turn the built-in potentiometer clock-
wise.
To decrease the output voltage, turn it counterclockwise.
¡
The power supplies have an external output voltage control func-
tion. The output voltage can be adjusted by changing the voltage
between the terminal TRM and the terminal COM on CN1/CN2.
You can decrease the voltage by drawing a current from the TRM
terminal.
You can calculate the output voltage in this case from formula
1
below.
Please do not apply +5V or more or negative voltage between
TRM and COM. Please contact us if you need accurate numbers.
Please do not apply negative Voltage to TRM terminal.
There is more than one method to adjust the output voltage, in-
cluding the methods to use external resistors and external power
supplies. Since each method has different characteristic, please
contact us for details.
Output voltage =
X
rated output voltage
---1
The voltage between
TRM and COM
2.5 [V]
If the output voltage decreases to 60% or less of rated voltage,
output ripple may increase.
Table 2.1 Output voltage adjustment range
Model
Output voltage adjustment range [V]
FETA7000ST-48
approximately 0 to 52.8
FETA7000ST-144
approximately
0 to 158.4
2.7 Output Ripple and Ripple Noise
¡
Output ripple noise may be influenced by measurement environ-
ment, measuring method Fig.2.1 is recommended.
+Vout
-Vout
Load
150mm
C
1
Oscilloscope
Bw:500MHz
Differential probe
+
C
1 :
Aluminum electrolytic capacitor 22μF
Fig.2.1 Measuring method of Ripple and Ripple Noise
Remarks :
When GND cable of probe with flux of magnetic force from power
supply are crossing, ripple and ripple noise might not measure
correctly.
Please note the measuring environment.
150mm
Bad example
Good example
Fig.2.2. Example of measuring output ripple and ripple noise
AC-DC Power Supplies Enclosed Type
Instruction Manual
FETA-9