6
HRRS 5kV and 10kV Series
Maintenance
Chapter 4
MAINTENANCE
4.1 Maintainability and Reliability
It is possible to maintain models HRRS-5kV and
HRRS-10kV inde
fi
nitely. They are reliable due to
their closed design and sealed switches and resistors.
The units are resistant to electromagnetic interference
(EMI) because of their metal enclosure.
4.2
Preventive Maintenance
Keep the units in a clean environment. This will help
prevent possible contamination.
The front panel should be periodically cleaned to
eliminate any leakage paths from near or around the
binding posts. To clean the front panel:
Wipe the front panel clean using alcohol and a
lint-free cloth.
4.3 Verifi cation of Performance
4.3.1 Calibration
Interval
The HRRS 5kV and 10kV Series instruments should
be veri
fi
ed for performance at a calibration interval of
twelve (12) months. This procedure may be carried
out by the user if a calibration capability is available,
by IET Labs, or by a certi
fi
ed calibration laboratory.
If the user should choose to perform this procedure,
then the considerations below should be observed.
4.3.2 General
Considerations
It is important, whenever testing the HRRS 5kV and
10kV Series units, to be aware of the capabilities and
limitations of the test instruments used. A resistance
bridge may be employed, and there are direct-reading
resistance meters or digital multimeters available
that can verify the accuracy of these units, especially
when used in conjunction with standards that can
serve to con
fi
rm or improve the accuracy of the test-
ing instrument
Such test instruments must have a 4:1 TUR capabil-
ity for each value calibrated. Note that the accuracy
varies for different decades. A number of commercial
bridges and meters exist that can perform this task;
consult IET Labs.
It is important to allow both the testing instrument
and the HRRS-5kV/10kV Substituter to stabilize for
a number of hours at the nominal operating tempera-
ture of 23°C, and at nominal laboratory conditions of
humidity. There should be no temperature gradients
across the unit under test.