Maintenance and care
Repetition test
32
Item No.: 099-002032-EWM01
7.3.5
Measurement of insulation resistance
The mains switch must be on before the insulation in the interior of the machine through to the
transformer can be checked. If a mains contactor is fitted, this should be bridged or the measurement
must be carried out on both sides.
The insulation resistance must not be less than:
Input power circuit
(mains)
against Welding current circuit and
electronics
5 M
Ω
at test voltage 1000V=
Input power circuit
(mains)
against Casing
(PE)
2.5 M
Ω
at test voltage 500V =
Welding current
circuit and
electronics
against Casing
(PE)
2.5 M
Ω
at test voltage 500V =
7.3.6
Measuring the leakage current (protective conductor and contact current)
These measurements cannot be carried out with a normal multimeter. Even test devices for VDE 0702
(especially older devices) are generally only intended for 50/60Hz. With inverter welding machines,
however, significantly higher frequencies occur, which can interfere with some measuring devices, and
results in others measuring the frequency incorrectly.
Test devices must meet the requirements of VDE 0404-2. For the frequency response measurement,
please refer to DIN EN 61010-1 Appendix A – Measuring Circuit A1.
For these measurements the welding machine must be switched on and supplying open circuit
voltage.
1. Protective conductor current: <3.5mA
2. Contact current from welding sockets separately to PE: <10mA
3. Contact current of accessible, conductive parts not connected to PE, to PE: <0.5mA
7.3.7
Measuring the open circuit voltage
6u8F
10nF
0...5k
0k2
1k0
1N 4007
Measuring circuit according to DIN EN
60974-1
Connect the measuring circuit to the welding current
sockets. The voltmeter must display mean values and
have an internal resistance
≥
1 M
Ω
. In the case of step
switch controlled devices, set the maximum output voltage
(step switch). Adjust the potentiometer from 0 k
Ω
to 5 k
Ω
during the measurement. The measured voltage should
not deviate from that specified on the rating plate by more
than +/- 5% and may be no greater than 113 V (for devices
with VRD: 35 V).
7.3.8
Function test of the welding machine
Safety devices, selector switches and command units (if fitted) and the entire machine or the entire
system for arc welding, must be functioning perfectly.
1. Main switch
2. Emergency stop devices
3. Danger reduction devices
4. Gas solenoid valve
5. Message and control lamps
6. Command devices and selector switches (including remote controls)
7. Locks
