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9. Principle of How It Work
The tester has two separate circuits:
One is for the
3 Phase Presence and Rotation indicator
, the other
is for the
Earth leakage Circuit Breaker Tester.
The first circuit is the 3 Phase presence indicator, which is shown by
the neon lamps and the three phase sequence indicator by leds.
3 Phase Presence and Rotation indicator:
This circuit derive it's power from the system under test.
This circuit does not require the user of battery and is self powered
through resistors.
3 Phase Presence Indication circuit:
This circuit uses neon lamps to indicate if a phase is present.
These neon lamps are connected in series with a limiting resistor.
Neon lamps will lights up when the voltage across any two phases is
more than 100Vac.
3 Phase sequence indicator circuit:
This circuit has an analog and a digital part. The analog signals are
shaped then compared to a set of references. These results are
digitally compared to give the results on the indicating LEDs.
Earth leakage Circuit Breaker Tester
At switch-ON, the circuit is powered up.
A low battery detection pickup circuit, with a Power On indicator LED
is also present.
This LED indicate that the batteries are ok and it will lights up when
the batteries are ok.
Should this led not lights up, replace the batteries.
Once the Earth Leakage Circuit Breaker is turned-ON, the first menu
will indicate that the instrument is ready.