METREL MI 3399, Инструкция с упражнениями

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PAT Appliances & Machines Safety Trainer AD 3
– MI 3399
231
Measuring principle /limits
Figure 4-27: Examples of clamp current tests
Appliance is powered on. By embracing separate conductors load or leakage currents
can be measured.
Notes:

For leakage current measurements special current clamps must be used (eg
METREL A1019)

If large load currents (>1A) are present in the nearness they would almost
certainly disturb the leakage current results (too high readings).

It is advisable that the user learns to become familiar with the influence of
external fields. If the source of disturbance is known the influence can be
minimized by using different techniques (changing the position of the clamp,
placing the clamp close to earth potential, searching for the minimal reading etc).

If in doubt it is recommended to use other leakage measuring methods.

If leakage currents differ for different appliance operating modes all modes must
be checked. The highest result must be considered!

If the position of line and neutral conductor in the installation or appliance plug is
not predefined, the test must be performed in both directions with higher result
considered.

The current clamp measurement is well suited for fixed installed equipment.
4.4.11 Functional test
Scope of test
In its simplest form a functional check is simply a check to ensure that the appliance is
working properly. The use of more sophisticated measuring instruments permits load
testing, which is an effective way of determination if there are faults in the appliance.
Functional check explores if the appliance is working properly. The use of more sophisticated measuring
instruments permits load testing, which is an effective way of determination if there are faults in the
appliance.