IEC 61204-3:2011 pdf – Low-voltage power supplies, d.c. output 一Part 3: Electromagnetic compatibility (EMC).
critical frequency of a PSU
the frequency, the wavelength of which is equal to tour times the longest side length of the Psu
residual voltage (of voltage dip)
the minimum value of r.m.s voltage recorded during a voltage dip or short Interruption
NOTE The residual voltage may be expressed as a value in volts, 01 as a percentage or per unit value relative to the referenc, voltage
4 Applicability ot tests to different PSU technologies Guidance on this issue is given in Annex A.
5 General requirements and test conditions
5i General requirements
The manufacturer of the PSU has a responsibility to provide information relating to the EMC performance, application, intended environment and installation guidelines for the product.
5.2 Test conditions
The tests shaI be Performed using the manufacturer’s recommended wiring and installation
instructions. There will be no connections other than those specified by the manufacturer. The configuration, orientation and electrical test conditions of the PSU shall be representative of the worst case in-service conditions. it known- Otherwise, all measurements shall be performed at rated nominal input voltage, full rated load and ambient temperature between 15 C and 35 C. The PSU shall be at its normal operating temperature.
The load is presumed not to generate any electromagnetic Interference. Load resistors may be cooled by a tan or cooling fluid.
All tests specified in this standard are type tests only.
The equipment shall meet the requirements when measured by the test methods specified.
No additional EMC tests are required or necessary beyond those stated in this standard.
Precautions shall be taken against the EUT (equipment under test) becoming dangerous or
unsafe as a result of the immunity tests specified in this standard. 6 Emission requirements
If the cable arrangements of the application are known, then those shall be used. It they are not known, the arrangements shall be chosen in accordance with 6.2 and 6.3. The measuring conditions shall be stated in the documentation.
6.1 Low frequency phenomena (f S 9 kHz; ac. input only)
6-1.1 Commutation notches
In this subclause, only PSUs with commutation of the primary current are covered. PSUs of high power designed as line commutated converters may cause notches if connected to a high impedance Source. Measurements or calculations are not mandatory. Information and recommendations are given in Annex B.
61.2 Current harmonics and interharmonics
The limits for PSUs connected to a public mains supply up to and including a rated input current 01 16 A are given in IEC 61000-3-2. This requirement is applicable to apparatus and components considered as apparatus covered within the scope of IEC 61000-3-2.
Harmonic measurements, especially on PSUs, are sensitive to the voltage source. In many cases, the public mains supply may not be a suitable source for this purpose.
Therefore, one of the following methods shall be used.
a) Using a public mains supply in accordance with IEC 6 1000-3-2:
— the limits for the harmonics of the voltage source shall be met with the PSU operating at full rated load.
b) Using an artificial supply in accordance with IEC 61000-3-2.
C) Calculation or simulation if it takes into account:
— the voltage source as an ideal sine wave;
— the worst case internal impedance of the PSU in the frequency range from the line frequency up to the 40th harmonic.
For recommendations: see Annex C. lnterharmonics may occur under specific load conditions which cannot be taken into account in this standard; this system aspect is the responsibility of the user, installer.
NOTE Limits lot harmonic currents produced by equipment Connected to public low-voltage systems with input current >16 A and 575 A par phase are given IEC 61000-3-12.
6.1,3 Voltage fluctuations and flicker
The limits for PSUs connected to a public mains supply up to and Including a rated Input current of 16 A are given in IEC 61000-3-3. This requirement is applicable to apparatus and components considered as apparatus covered within the scope of IEC 6 1000-3.3, but it is not mandatory for PSUs used in countries where there are no regulations requiring voltage fluctuations and flicker limits.