IEC 61000-3-3 pdf free download
IEC 61000-3-3 pdf free download.Electromagnetic compatibility (EMC) – Part 3-3: Limits – Limitation of voltage changes, voltage fluctuations and flicker in public low-voltage supply systems, for equipment with rated current≤16 A per phase and not subject to conditional connection.
6.2 Measurement uncertainty
The magnitude of the current shall be measured with an accuracy of ± (1 % + 10 mA) or better, where the 1 % is referred to the measured value, If, instead of active and reactive current, the phase angle is used, its error shall not exceed ± 2°.
The directly measured parameters (see Clauses 3 and 4) shall be determined with a total uncertainty better than ± 8 % of the limit value, or ± 8 % of the measured value, whichever is higher. The total impedance of the circuit, excluding the appliance under test, but including the internal impedance of the supply source, shall be equal to the reference impedance. The stability and tolerance of this total impedance shall be adequate to ensure that the overall uncertainty of ± 8 % is achieved during the whole assessment procedure.
If the source impedance is not well defined, for example where the source impedance is subject to unpredictable variations, an impedance having resistance and inductance equal to the reference impedance may be connected between the supply and the terminals of the equipment under test. Measurements can then be made of the voltages at the source side of the reference impedance and at the equipment terminals. In that case, the maximum relative voltage change, dmax, measured at the supply terminals shall be less than 20 % of the maximum value dmax measured at the equipment terminals.
NOTE The above method using a voltage source with undefined impedance is not used where the measured
values are close to the limits.
6.3 Test supply voltage
The test supply voltage (open-circuit voltage) shall be the rated voltage of the equipment. If a
voltage range is stipulated for the equipment, the test voltage shall be 230 V single-phase or
400 V three-phase. The test voltage shall be maintained within ± 2 % of the nominal value.
The frequency shall be 50 Hz ± 0,25 Hz.
The percentage total harmonic distortion of the supply voltage shall be less than 3 %.
Fluctuations of the test supply voltage during a test may be neglected if the P value, produced from these fluctuations, is less than 0,4. If the measurements are made directly using the mains supply, this condition shall be verified before and after each test. If measurements are made using a controlled power source, this condition shall be verified during calibration of the power source.
NOTE Frequency deviations can cause the measured P, and P11 values to increase. Also, when testing a flicker meter response according to Tables lb and 2b in lE 61000-4-15: 2010, the 50 Hz frequency is preferably controlled to within ± 0,25 Hz.
6.4 Reference impedance
For equipment under test the reference impedance, Zref according to IEC/TR 60725, is a conventional impedance used in the calculation and measurement of the directly measured parameters, and the and PQ values.IEC 61000-3-3 pdf download.
