UL 60939-3-2017 pdf free download

UL 60939-3-2017 pdf free download.Passive Filter Units for Electromagnetic Interference Suppression — Part 3: Passive Filter Units for Which Safety Tests are Appropriate.
3.2 Safety approval procedure
3.2.1 General
Table 3 and Annex B form a schedule, which is limited to tests concerning safety only requirements. The schedule to be used for safety only approval will be on the basis of fixed sample sizes according to 3.2 as given in 3.2.3 and Table 3 of this specification. Prior to the approval testing being carried out, it is necessary to submit to the certification body a declaration of design (Annex E) registering essential data and basic design details of the passive filters for which approval is sought.
If subsequent to the granting of approval, any component is changed, the certification body shall be informed (see Annex E). Extension of approval to include changed component(s) is at the discretion of the certification body.
3.2.2 Sampling
Filter types to be qualified together shall have the same rated voltage, and same combination of component and construction technologies. In addition, the corresponding capacitive elements shall be of the same subclass. The numbers of filters required for the qualification in each group are given in Table 3.
For the qualification, the sample shall contain equal numbers of specimens of the highest and lowest total capacitance values in the range to be qualified. Where only one total capacitance value is involved, the total number of filters as stated in Table 3 shall be tested.
Ii, for a given value of total capacitance, there is more than one RATED CURRENT available in the range, then filters with the highest RATED CURRENT shall be chosen. If at this RATED CURRENT more than one Inductance value is available in the range, then filters with the highest inductance value shall be chosen.
NOTE ‘Total capacitance in the paragraph above means the given NOUINAL CAPAC1TA7 between the input terrn,riabons of the titter.
Spare specimens are permitted as follows:
a) one per value which may be used to replace the non-conforming item in group 0;
b) one per value which may be used as replacements for non-conforming specimens because of incidents not attributable to the manufacturer;
c) sufficient specimens to enable the repeat test of Footnote 7 to Table 4 to be carried out.
The numbers given in Group 0 assume that all further groups are applicable. If this is not so, the numbers may be reduced accordingly. The numbers given in Group 0 may also be reduced if. for example for expensive filters, the manufacturer chooses to carry out the tests of a number of groups in sequence on the same specimens. The numbers given for Group 0 do not include the specimens required for Groups 4.UL 60939-3-2017 pdf free download.