40
- Shift the mains switch to the “O” position and unplug the machine from the mains
- Connect the shunt and power resistor to the welding sockets of the power source
- Set the welding-current dial to Minimum
Checking the
minimum
welding
amperage
(continued)
It is recommended to measure the open-circuit voltage as a peak value. For taking this
measurement, use the specially designed measuring circuit.
In the drawing, the measuring circuit can be found beneath the heading “Variant 1:
Measuring the peak value using the measuring circuit”.
Alternatively, if the measuring circuit is no longer available, the RMS value can be
measured.
Note!
The RMS value can only be of any help in detecting a defect in the
power source in the event of very severe deviations from the desired value.
Variant 1:
Measuring the peak value using the measuring circuit
Fig.5
Checking the open-circuit voltage
-
Variant 1: Measuring the peak value using the measuring circuit
+
-
TP 1500
V
6.8 uF
10 nF
1N4007 or
equivalent
1 kOhm
0,2
kOhm
0 - 5
kOhm
U
0
Checking the
open-circuit
voltage
- Set up the measuring circuit as shown in the illustration above
- Shift the mains switch to “O” and unplug the machine from the mains
- Connect the measuring circuit, together with the voltmeter, to the welding sockets
- Plug the machine back into the mains and shift the mains switch to “I”
- Set the welding-current dial to Maximum
- Select the welding process “rod-electrode welding“
- Peak value of open-circuit voltage = approx. 92 V
DC
- Tolerance range = +/-10V
DC
if the variable resistor of the measuring circuit is set to
5 kOhm
If the open-circuit voltage is not within the tolerance range, this may mean that the
LCA15 board or the potentiometer are faulty.
Warnung!
An electric shock can be fatal. This test is performed with the power
source switched on and the housing opened up. As long as the power source is
plugged into the mains, do NOT under any circumstances touch the power
source or any of its components. Follow these instructions even after
unplugging the power source from the mains. The capacitors are still charged -
and still very dangerous!
Open the housing (see the section headed: “Opening the housing”)
- Plug the machine into the mains and shift the mains switch to the “I” position
- Select the welding process “rod-electrode welding“
- Measure the minimum welding current using the shunt and power resistor
- Adjust the potentiometer (2) - Fig.3 - on the LCA15 board, until the exact value for
the maximum welding current (10 A) is reached
- I
min
= 10 A
Содержание TP 1500
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