Ri Insulation Measurements; Measuring Ac Current - Metrix MX 435D Notice De Fonctionnement

If an "I" is displayed in 2000 , the earth is bad because the earth rod must have a
resistance of <100 Ω to make the evacuation of the fault current possible in compliance with
NF C15-100.
3.4.

Ri Insulation Measurements

High voltage is generated at the terminals of the resistance to be measured. The voltage
drop measured at the terminals of a known internal resistance, in series with the resistance
to be measured, is used to deduce the value of this resistance.
Tests must be carried out only on off circuits [the
(Risk of electrical shock) on the instrument's front panel must be off].
If mains voltage is present before measuring, the instrument is protected up to 480 Vrms.
The instrument returns to normal measuring conditions in approximately 1 min.
Measurement results may be distorted by impedance from additional circuits connected in
parallel or by transient currents.
Method:
• Turn the selector switch to Ri MΩ.
• Connect the test leads to "+" and "-" MΩ terminals on the instrument.
• Connect them to the resistance you wish to measure.
• Keep the "TEST" pushbutton pressed down until the measurement becomes stable.
Voltage of ca. 500 V is generated.
• The high voltage present in the tested circuit is discharged into the instrument via
the test leads, through a 10 MΩ resistance. Once the measurement is finished,
leave the instrument connected for a few seconds.
For measurements in relation to the earth, it is preferable to connect the "+" terminal
to the earth.
If an "I" is displayed, the range has been exceeded; this means that the measurement
is greater than the upper limit, i.e. 200 MΩ.
The measurement is therefore correct since NF C 15-100 requires an insulation
measurement > 0.5 M for an injected test voltage of 500 V
3.5.

Measuring AC current

Currents and leak currents can be measured with this tester, provided a current clamp is
used.
The AM0019N clamp enables measurements to be performed on 2 ranges: 2 A and 200 A.
• In the 2 A range, the value is read directly on the LCD screen in mA, with a
sensitivity of 1 digit/mA.
• In the 200 A range, the reading sensitivity is 10 digits/A.
The result displayed on the LCD screen must therefore be divided by 10 to
obtain the exact value in A.
This clamp enables leak currents, due to installation insulation problems, for example, to be
measured, without cutting the circuits, i.e. in total safety.
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