Portable Surge Protective Device Tester
VII. Help for Tester Measurement (measurement by third-party institutions)
Note: It is recommended to choose a MOV with break-over voltage of 620V ± 5%
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1. Verification of current 1mA
(1) Principle: the testing equipment generates a 1mA constant current source
(2) Wiring diagram on the right
(3) Operation steps: Press FUCNTION KEY to select Function 2 (the index on
the screen points to 2), then press “TEST KEY to generate current, verify
whether the current is 1mA, then press FUNCTION KEY to exit.
Related page: Accurate Testing and Calibration of MOV break-over Voltage
(Page 10)
2. Verify Voltage
(1) Principle: The testing equipment generates a current of 1mA. When the
current of 1mA flows through the varistor, a voltage is generated across the
varistor. This voltage is the varistor’s break-over voltage. Different varistors
have various break-over voltages
(2) Wiring diagram on the right:
(3) Operation steps: press FUNCTION KEY to select Function 2 (the index on
the screen points to 2), then press TEST KEY to generate current, and verify
the voltage displayed on the tester with the voltage in calibration table, and
then press FUNCTION KEY to exit
Related pages: Accurate Testing and Calibration of MOV Turn-On Voltage
(Page 10)
3. Verify Leakage Current
(1) Principle: apply 75% of the break-over voltage to both terminals of the
varistor. At this time, the current flowing through the varistor is leakage current,
which is generally a μA level current.
(2) Wiring diagram on the right:
(3) Operation steps: Press FUNCTION KEY to select Function 3 (the indicator
on the screen points to 3), and then press TEST KEY. At this time, the tester
generates a 1mA current, measures the break-over voltage of the varistor; then
applies 75% of the break-over voltage, the display will alternately show 75% of
the break-over voltage and leakage current, then verify the tester leakage
current, and then press the FUNCTION KEY to exit
Related pages: Accurate MOV leakage current calibration and leakage current
calibration (Page 11)
