DIN EN 60939-3:2016-09

This specification covers passive filters used to attenuate unwanted radio-frequency signals (such as noise or interference) generated from electromagnetic sources. Both single and multi-channel filters within one enclosure or which are built on a printed circuit board forming a compact entity are included within the scope of this specification. Filters constructed of capacitive elements where the inductance is inherent in the construction of the filter are within the scope of this specification. Similarly, filters constructed of inductive elements where the capacitance is inherent in the construction of the filter are also within the scope of this specification. It is up to the manufacturer to state whether a given component is to be designed as a capacitor, an inductor or a filter. Filters can include also other components like resistors and/or varistors or similar components. This specification applies to passive filter units for electromagnetic interference suppression for which safety tests are appropriate. This implies that filters specified according to this specification will either be connected to mains supplies, necessarily applying the prescribed tests, or used in other circuit positions where the equipment specification prescribes that some or all of these safety tests are required. This specification applies to passive filter units, which will be connected to the mains supply or connected to other voltage sources (d.c. or a.c.) with a nominal voltage not exceeding 1000 V a.c., with a nominal frequency not exceeding 400 Hz, or 1500 V d.c. Class X capacitor is a capacitor or RC unit for applications where the failure of the capacitor does not result in a dangerous electric shock, but may cause a fire. X capacitors are divided into two subclasses according to the voltage spikes of pulses superimposed on the line voltage to which they are subjected during operation. Such pulses can be caused by lightning strikes in overhead lines, switching operations in neighboring equipment or in the equipment in which the capacitor is installed. Class Y capacitor is a capacitor or RC unit for applications where the failure of the capacitor can lead to a dangerous electric shock. Y capacitors are divided into three subclasses Y1, Y2 and Y4. A Y capacitor is allowed to bridge the basic insulation. A Y capacitor is allowed to bridge the additional insulation. If two Y2 or Y4 capacitors connected in a series bridge the combination of base insulation and additional insulation, then they shall have the same rating. In AC applications, Y capacitors may be replaced by two X capacitors connected in series, provided the rated voltages of the X capacitors are not less than the rated voltage of the Y capacitor and the filter passes the voltage test. If a Y1 capacitor is replaced, then the X capacitors shall be X1 capacitors. In a DC filter with a rated DC voltage of 150 V or less, a Y2 and Y4 capacitor may be replaced by an X capacitor with a rated DC voltage of 250 V or greater. Different types of filters are distinguished: - Radio interference suppression filter: assembly of components and inductive, capacitive and resistive elements used to reduce electromagnetic interference caused by electrical or electronic equipment or by other sources. - Line filter: passive filter essentially designed to operate on AC line voltages with frequencies that occur in the power range. - DC filter: passive filter essentially designed to operate on a DC power supply: typical DC filters are photovoltaic filters used with inverters/converters and so on, placed between the solar module and the converter, or DC filters for telephone network lines. - Equipment filter: filter intended for factory installation in terminal equipment or devices connected to (fed by) the final circuit of a building wiring system. The leakage current of an electromagnetic interference suppression filter is a current flowing to ground or to an external conductive part in a faultless circuit. This current may have a capacitive component, caused mainly by the use of capacitors. The leakage current calculated according to this standard is a theoretical value. The specification of this value in data sheets allows customers to compare filters. The actual leakage current for each application cannot be specified because it depends on many parameters. The responsible committee is DKE/K 623 "Funk-Entstörmittel" ("Capacitors and resistors for electronic equipment") of the DKE (German Commission for Electrical, Electronic and Information Technologies) at DIN and VDE.