The GB4706.1 residual voltage tester is used to verify whether the attenuation of residual voltage in the internal circuit of household appliances after power failure meets safety requirements and avoids the risk of electric shock for users. The following is the standard usage method:
Confirm that the test object complies with GB4706.1 "Safety of household and similar electrical appliances - Part 1: General requirements", and clarify whether the equipment belongs to the type with energy storage components such as capacitors and inductors.
Preparation of instruments: Select an AC voltmeter (or multimeter AC voltage range) with an accuracy of ≥ ± 2%. The test probe should be compatible with the equipment interface to ensure good insulation performance.
Check the equipment status: The appearance of the tested electrical appliance is undamaged, the circuit connection is normal, and it is in a working state; The testing environment temperature is 15 ℃~35 ℃, and the relative humidity is 10%~75%.
Connecting instruments: Connect the voltmeter probe to the power input terminal of the device, or to exposed and accessible parts that may have residual voltage, ensuring firm wiring and good contact.
Power on electrical appliances: Connect the power supply according to the rated voltage of the equipment, and let the electrical appliances run normally to a stable state (such as motor equipment running for 5 minutes and capacitor equipment fully charged).
Cut off the power and timer: Quickly disconnect the power switch (or unplug the power plug) and start the timer to record the initial residual voltage value at the moment of power failure.
Periodic voltage measurement: According to standard requirements, residual voltage should be measured at 0.1 seconds, 1 second, 5 seconds, and 10 seconds after power failure. Some equipment needs to be supplemented with measurements at specific time nodes (such as the time when capacitors discharge to safe voltage).
Record data: Accurately record the voltage values at each time point, draw the voltage decay curve (optional), and ensure data traceability.
Judgment criteria: Within 1 second after power failure, the residual voltage should be ≤ 34V (effective value); Within 10 seconds after power failure, the residual voltage needs to decay to ≤ 60V (peak value), and the specific threshold should be adjusted according to the equipment type and standard terms.
Exception handling: If the residual voltage attenuation does not meet the standard, it is necessary to check whether the equipment discharge circuit (such as the discharge resistor) is normal and optimize the discharge design of the energy storage component.
Safety precautions: Insulated gloves should be worn during testing to avoid direct contact with live terminals; After the equipment is powered off, there may still be instantaneous high voltage. It is strictly prohibited to touch the testing area before measurement.