ISA T2000, Руководство пользователя

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DOC. MIE11110 Rev. 5 Page 75 of 110
- N. 1 cable for low voltage measurement connection, shielded, 4
m long, for the 10 V measurement, plus N. 2 Clamps to connect
the voltage measurement.
Prior to the test, you can select if the test result has to be
compensated taking into account the temperature, and computed
to a reference temperature (as specified for the CT). Once
enabled the compensation, the operator:
. Selects the temperature scale, °C or °F;
. Inputs the ambient temp erature, as measured on the CT;
. Inputs the reference temperature at which the resistance will be
reported.
Press test start button (56), and adjust the test current to the
desired value by the adjustment knob (6): the screen shows:
. The test current;
. The corresponding voltage drop;
. The ohm burden at the ambient temperature;
. The ohm burden at reference temperature.
These measurements will not change very much with the test
current; however, it is advisable to use the same test current for
each phase.
Given the delay of the current growth caused by the inductance,
you should not save the result until the value is stable enough.
The following message tells you how much the resistance
measurement is changing.
When the measurement is stable enough (for instance, less than
1%/s), press SAVE: test result is saved. Return to zero the
adjustment knob (6).
NOTE: T 2000 does not have a stable current source: it follows
the mains variations. With slow changing mains values, the
resistance measurement is stable enough, as it is the ratio,
measured at the meantime, of voltage versus current; so, there
can be a problem of unstable resistance measurement only in case
of highly unstable mains, with fast changes.