T&R Z-OVR, Operating And Maintenance Manual

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1.3.2 Metering
The Z-OVR is fitted with a true rms ammeter and voltmeter with hold facility.
1.3.2.1 Ammeter ranges
Figure 1.9 Ammeter
Four true rms current metering ranges are provided. The range is selected using the AMMETER
switch on the control unit. A current trip is set at 105% of the full scale of the range.
Ammeter range
Metering full
scale
Resolution Accuracy Trip current
2A 2.000A 0.001A ±1%rdg+5d 2.1A
10A 10.00A 0.01A ±1%rdg+5d 10.5A
20A 20.00A 0.01A ±1%rdg+5d 21A
100A 100.0A 0.1A ±1%rdg+5d 105A
1.3.2.2 Voltmeter ranges
Figure 1.10 Voltmeter
Three true rms voltage metering ranges are provided. The range is set using the VOLTMETER
switch on the control unit. The voltage measuring input is isolated by a switched range VT. The
VT provides safety isolation from the line under test, but has a relatively low input impedance
on the 10V and 30V ranges. Do not use the 10V or 30V range with test currents of less than 5A
to maintain accuracy.
Caution
Ensure that the maximum voltage applied to the voltage input does not exceed the
range selected. Fuses are provided on the input to protect the VT. If the voltage
for the range selected is too high the fuses on the VT input will blow.
I ¢ V
10.00A 90.0° 1.00V
IMPEDANCE
Z=100.0m© X=100.0m©
I ¢ V
10.00A 90.0° 1.00V
IMPEDANCE
Z=100.0m© X=100.0m©