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Maintenance and Calibration
Maintenance, repair, and calibration of a high-voltage test set require
specialized expertise and equipment, and are not suitable for DIY
enthusiasts. The voltages involved pose significant dangers, and
precise calibration of both the voltmeter and trip current is essential,
particularly when testing to CSA or UL certification standards.
It is strongly recommended that your test set undergo a thorough
check of its operation and calibration at least once a year by Criterion
Instruments or an authorized Criterion Instruments Service Centre.
More frequent checks may be necessary if the equipment is used
extensively, and immediate attention is warranted if any malfunction is
observed or suspected.
Trip Current/Milliammeter Calibration:
High-voltage testers typically operate with a capacitive load, and it
is advisable to test them accordingly. Some standards mandate this
practice. Utilize a 0.25-uF capacitor with a minimum AC voltage rating
of 5kV for loading purposes.
To check trip current sensitivity, connect the capacitor in series with
an AC standard milliammeter (traceable if needed) in place of the test
sample, ensuring proper grounding. The capacitor and meter should
be placed on an adequately insulated surface.
Ensure the VOLTAGE ADJUST Knob is set to zero (fully counter
clockwise), then power on the tester and press the RESET button.
Slowly adjust the VOLTAGE ADJUST Knob clockwise, monitoring the
milliammeter (disregarding the voltmeter reading). Record the current
at which the cut-out operates, repeating the process to validate
consistency. Ideally, this value should fall between 95.0 and 97.5 mA.
The internal milliammeter should display the same reading as the
external standard being utilized.
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