●
Terminal connection of insulation resistance test
In case of testing insulation of insulated wire and cable against the earth
at direct current, connecting - pole of power to cable conductor, + to the
earth obtains smaller measuring value, compared with connecting the
other way round. This connecting method is generally acknowledged
relevant to detect defective insulation.
6-3 Continuity Measurement (Resistance Tests)
DANGER
●
Always test the circuit or equipment to ensure it is surely de-energized
before measurement according to the instruction of 6-1.
●
To avoid electrical shock, measurements must be performed on de-
energized circuits only.
●
Never make measurement with the battery compartment cover
removed.
CAUTION
●
Never press the test button if the live circuit warning is indicated or the
warning buzzer sounds. This may damage the circuit.
●
When an additional circuit is connected in parallel with the circuit under
test , inaccurate reading may be taken.
①
Set the function switch to the "AUTO NULL" position.
②
Short the test probes (red) and (black) and press the test button. Then the
resistance of the test probes is displayed and memorized with
microprocessor.
③
Set the function switch to "
Ω
" position.
④
Connect the test probes to the circuit under test and press the test button.
⑤
Read the resistance value from the LCD.
●
NULL symbol (
) is displayed while AUTO NULL function is working.
●
AUTO NULL will be cancelled when the instrument is powered off.
●
Principle of Continuity Measurement (Resistance Test)
Resistance value can be obtained by applying a certain current to the
resistance under test and measuring the voltage generated on the both
sides of the resistor under test.
Resistance value = Voltage / Current
RX = V / I
6-4 Continuous Measurement
A lock down feature is incorporated on the test button. Pressing and
turning it clockwise, lock the test button in the continuous operating
position.
To release the lock, turn the test button counterclockwise.
DANGER
Be extremely careful not to get electric shock during insulation resistance
measurement as high voltage is present on the tip of test probes
continuously.
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