Benning ST 755+ - Page 73

Testing
9.1 Requirements for tests and measurements
5284 / 08/2023 en BENNING ST 755+ / ST 760+ 73
– If, for insulating resistance measurement, not all parts are measured completely (e.g. if
relays or semiconductor components impede the transmission of electricity), the
alternative leakage current measuring method must not be applied. The direct current
measuring method or the differential current measuring method is applied.
– If the insulating resistance measurement of devices with heating elements >3.5kW has
been terminated with a negative result, the alternative leakage current measuring
method must not be applied. The direct current measuring method or the differential
current measuring method is applied.
• Protective conductor resistance:
– During the protective conductor measurement, move all movable individual parts of the
protective conductor section.
– For test samples with long connecting cables and a protective conductor resistance
>1Ω, the operator of the test sample must be informed that the loop impedance of the
circuit might become too high and that the test sample should be used with a residual
current protection device (RCD).
– If there is a significant change of the measured resistance value when the protective
conductor is moved, it must be assumed that the protective conductor is not properly
connected or damaged or that one of the terminal or plug connections has lost contact
with the test sample.
Functional test
• The test sample must only be tested for proper functioning after it has passed the safety
test!
• For the direct and differential current measuring method, the test socket is supplied with
mains voltage.
• Measurement with both polarities (L<->N; N<->L)
• For the direct current measuring method, the test sample is placed onto an insulated
surface.
• Please prove, before carrying out the functional test and all tests for which the test sample is
supplied with mains voltage and put into operation, that there are no short-circuits in the test
sample within phases L1, L2, L3 and the neutral conductor N.
• Before starting the functional test, switch off the test sample at the device's own switch. Do
not switch on the test sample until the corresponding query appears on the display of the
device.
• In case of test samples which are connected to each other via fastenings or are galvanically
isolated from each other or have a common protective conductor: Please test each
component individually.
Testing of welding equipment
• Please observe the ignition voltage of the welding equipment. Please test only welding
devices with voltages<200V‑DC and <150V‑AC.
• The test socket is supplied with mains voltage.
• For TIG and plasma welding devices, the output voltage (U
a
weld.) must not be measured
with the device.
• To set the limits, please observe the information stated on the type plate of your welding
device and the overview of specifications stated in the relevant standards.
• The device uses a digital potentiometer to realise the load of the welding device. The load
starts as soon as at least half of the limit of the welding voltage has been reached. The load
duration is 3seconds.