6.2 Breakdown vs. burn mode
In breakdown mode insulation tests are automatically stopped and Brd displayed 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
6.3 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
6.4 Reset Default Settings
Remove AC source, press OK, backlight buttons and switch main rotary switch from OFF to setting icon.
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S1-568 / S1-1068 / S1-1568
10
Operating Instructions
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