Chauvin Arnoux C.A 6550, Руководство пользователя

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4. CoMPLEMENtAry fUNCtIoNS
4.1. tEMP kEy
This function is accessible only when the measurement is over. It is used to refer the measurement result to a temperature other
that the one at which the measurement was made.
This is because the temperature causes the resistance to vary according to a quasi exponential law. To a rough approximation,
raising the temperature by 10°C halves the insulation resistance; conversely, lowering the temperature by 10°C doubles the
insulation resistance.
Referring the measurements to a single temperature makes it easier to compare them and gives a better idea of the evolution of
the insulation resistance. And this is true whatever the temperature at the time of the measurement.
Similarly, measuring the humidity improves the correlation between the various measurements made on a given device.
Procedure:
„
Make a measurement in U-FIXED or U-VAR mode.
„ Press the TEMP key.
TEMPERATURE
Air Temperature
Humidity
Probe Temperature
Rc Reference Temperature
∆
T for R/2
--- °C
--- %
--- °C
--- °C
--- °C
R measured
Rc at
--- °C
5.00 G
Ω
--- k
Ω
TEMPERATURE
Air Temperature
Humidity
Probe Temperature
Rc Reference Temperature
∆
T for R/2
23 °C
40%
23 °C
40 °C
10 °C
R measured
Rc at 40 °C 5.00 G
Ω
1.529 G
Ω

TEMP
„ Use the   and  keys to enter the various parameters:
„
Air Temperature: the ambient temperature (optional)
„
Humidity: the ambient relative humidity (optional)
„
Probe Temperature: the temperature of the device tested. If it has not warmed up during the measurement, it is equal
to the ambient temperature.
„
Rc Reference Temperature: the temperature to which the measured resistance will be referred.
„
∆
T for R/2: the temperature variation, known or estimated, sufficient to halve the insulation resistance.
To facilitate the programming, the instrument proposes default values.
„ The instrument then displays the insulation resistance referred to the reference temperature.
If coefficient
∆
T for R/2 is not known, it can be calculated from a minimum of 3 measurements made on the same device at
different temperatures.