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Breakdown vs. burn mode
In breakdown mode insulation tests are automatically stopped
when a fault causes the applied voltage to drop rapidly. Burn
mode IR tests ignore breakdown and continue to test the
insulation and are therefore destructive tests. Burn mode is used
to purposely create a carbon track in insulation to facilitate fault
location.
To enable measurements (IR, IR(t) modes) in very high noise
substations, breakdown mode is turned off automatically when
noise current exceeds 3.5 mA. Both breakdown and burn icons
are switched off and the breakdown detector is disabled. High
noise above 3.5 mA can appear to the instrument like a
breakdown which would halt an IR/IR(t) test. Burn mode is not
affected by the 3.5 mA limit.
To test for high noise select the voltmeter function and read the
voltage. A high voltage will indicate a high noise environment.
Voltmeter
A voltmeter is incorporated in the
instrument and measures AC/DC
voltage from 30 V to 660 V. Frequency
(Hz) is measured and displayed for AC
voltages. Voltmeter mode is activated
by switching to ‘V’ mode as illustrated.
Positive and negative terminals are used for the voltmeter
function; do not connect the GUARD terminal when in voltmeter
(V) mode.
To assist user safety, the instrument will automatically switch to
voltmeter mode if a voltage of 50 V or more is connected to the
terminals. The measured voltage will be displayed accompanied
by an intermittent beeper to warn the user that a dangerous
voltage exists.
For further explanation see, “Running an Insulation Test” on page
11.
Reset Default Settings
Remove AC source, press OK, backlight buttons and switch main
rotary switch from OFF to setting icon.
