IEC 61000-3-3:2021 pdf free download – Electromagnetic compatibility (EMC)
1 Scope
This part of lEC 61000 is concerned with the limitation of voltage fluctuations and flickerimpressed on the public low-voltage system.
lt specifies limits of voltage changes which may be produced by an equipment tested underspecified conditions and gives guidance on methods of assessment.
This part of lEC 61000 is applicable to electrical and electronic equipment having an inputcurrent equal to or less than 16 A per phase，intended to be connected to public low-voltagedistribution systems of between 220 v and 250 V line to neutral at 50 Hz, and not subject toconditional connection.
Equipment which does not comply with the limits of this part of lEC 61000 when tested withthe reference impedance Zre of 6.4,and which therefore cannot be declared compliant withthis part,may be retested or evaluated to show conformity with lEC 61000-3-11.Part 3-11 isapplicable to equipment with rated input current s 75 A per phase and subject to conditionalconnection.
The tests according to this part are type tests.Particular test conditions are given in Annex Aand the test circuit is shown in Figure 1.
NOTE 1 The limits in this standard relate to the voltage changes experienced by consumers connected at theinterface between the public supply low-voltage network and the equipment user’s installation.Consequently, if theactual impedance of the supply at the supply terminals of equipment connected within the equipment user’sinstallation exceeds the test impedance, it is possible that supply disturbance exceeding the limits could occur.
NOTE 2The limits in this standard are based mainly on the subjective severity of flicker imposed on the light from230 v 60 w coiled-coil filament lamps by fluctuations of the supply voltage. For systems with nominal voltage lessthan 220 V line to neutral and/or frequency of 60 Hz,the limits and reference circuit values are underconsideration.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document andare indispensable for its application. For dated references, only the edition cited applies.Forundated’references,the latest edition of the referenced document (including anyamendments) applies.
IEC/TR 60725,Consideration of reference impedances and public supply impedances for usein determining disturbance characteristics of electrical equipment having a rated current≤75 A per phase
IEC 60974-1，Arc welding equipment – Part 1: Welding power sources
IEC 61000-3-2，Electromagnetic compatibility (EMC) – Part 3-2: Limits – Limits for harmoniccurrent emissions (equipment input current s 16 A per phase)
6.1General
Tests need not be made on equipment which is unlikely to produce significant voltagefluctuations or flicker. Where it is considered necessary to conduct tests， the equipment shallcomply with all limits in Clause 5 for the tests described in Annex A unless there are specificexclusions for a particular type of equipment.
lt may be necessary to determine, by examination of the circuit diagram and specification ofthe equipment and by a short functional test, whether significant voltage fluctuations are likelyto be produced.
For voltage changes caused by manual switching，equipment is deemed to comply withoutfurther testing if the maximum ‘r.m.s. input current (including inrush current) evaluated overeach 10 ms half-period between zero-crossings does not exceed 20 A, and the supply currentafter inrush is within a variation band of 1,5 A.
lf measurement methods are used,the maximum relative voltage change dmax caused bymanual switching shall be measured in accordance with Annex B.
Tests to prove the compliance of the equipment with the limits shall be made using the testcircuit in Figure 1.