A unit automatically recovers when the fault condition is removed.
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.
1.6 Thermal Protection
¿
KHEA120F/240F/480F, KHNA120F/240F/480F
¡
A thermal protection circuit is built-in.
The thermal protection circuit may be activated under the follow-
ing conditions and shut down the output.
1
When a temperature continue to exceed the values determined
by the derating curve.
2
When a current exceeding the rated current is applied.
3
When convection stops.
4
When peak load is applied in conditions other than those shown
in Section 3.
A unit automatically recovers when the fault condition is removed.
1.7 Output Ripple and Ripple Noise
¡
Output ripple noise may be influenced by measurement environ-
ment, measuring method fig 1.1 is recommended.
+Vout
-Vout
150mm
C
2
C
1
+
Load
Osiloscope/
Ripple noise meter
Bw:20MHz
Differential probe
C
1
:Film capacitor 0.1
m
F
C
2
:Aluminum electrolytic capacitor 22
m
F
Fig.1.1 Measuring method of Ripple and Ripple Noise
1.8 Remote ON/OFF
¿
KHEA120F/240F/480F, KHNA120F/240F/480F
¡
You can reduce the standby power by Remote ON/OFF.
To do so, connect an external DC power supply and apply a volt-
age to a remote ON/OFF connector.
Table 1.2 Remote ON/OFF Specifications
ON/OFF logic
BRC and -RC
Output voltage
Negative
L level (0 to 0.5V) or open
ON
H level (4.5 to 29.5V)
OFF
Ri=2040
W
Input current
(20mA max)
-RC
+RC
*
1
R
SW
External Power
Souce
Inside of a Power
Supply
Fig.1.2 Example of use with remote ON/OFF
*
1 If the output of an external power supply is within the range of
4.5 - 29.5V, you do not need a current limiting resistor R. If the
output exceeds 29.5V, however, please connect the current limit-
ing resistor R.
To calculate a current limiting resistance value, please use the fol-
lowing equation.
Vcc-(1.1+Ri
X
0.005)
0.005
R [
W
]=
¡
Please wire carefully. If you wire wrongly, the internal components
of a unit may be damaged.
¡
Remote ON/OFF circuits (+RC and -RC) are isolated from input,
output and PE.
¡
Restart time is 750 ms max .
1.9 Output Voltage Adjustment Range
¡
To increase an output voltage, turn a built-in potentiometer clock-
wise. To decrease the output voltage, turn it counterclockwise.
1.10 Isolation
¡
When you run a Hi-Pot test as receiving inspection, gradually
increase the voltage to start. When you shut down, decrease the
voltage gradually by using a dial. Please avoid a Hi-Pot tester with
a timer because, when the timer is turned ON or OFF, it may gen-
erate a voltage a few times higher than the applied voltage.
¡
When you test a unit for isolation between the output and the
DC_OK, short all terminals of DC_OK.
1.11 Signal Output
Functions of LED indicators and signal output (KHEA series)
¿
KHEA120F/240F/480F, KHNA120F/240F/480F
¡
Functions of LED indicators and signal output in the form of relay
contact are shown below. Checking the presence/absence of volt-
age at the output terminal of a power supply is possible.
Table 1.3 Description of the signal output
Signal Output
Normal
Output is decreasing
DC_OK (LED: Green)
ON
OFF
ALARM (LED: Red)
OFF
ON
DC_OK (Relay Contact)
*
Short
Open
*
DC_OK signal (relay contact) is built in KHEA series. This circuit
is insulated from other circuits (input and output circuits).
Caution on signal outputs :
¡
The timing of signals might be very depending on models, input
and load conditions. Please make sure enough evaluation.
AC-DC Power Supplies DIN Rail Type
Instruction Manual
KH-23
June 29, 2020
