BS EN 61558-2-6:2009

1 Scope
2 Normative references
3 Terms and definitions
4 General requirements
5 General notes on tests
6 Ratings
7 Classification
8 Marking and other information
9 Protection against electric shock
10 Change of input voltage setting
11 Output voltage and output current under load
12 No-load output voltage
13 Short-circuit voltage
14 Heating
15 Short-circuit and overload protection
16 Mechanical strength
17 Protection against harmful ingress of dust,
   solid objects and moisture
18 Insulation resistance, dielectric strength and
   leakage current
19 Construction
20 Components
21 Internal wiring
22 Supply connection and other external flexible
   cable or cords
23 Terminals for external conductors
24 Provisions for protective earthing
25 Screws and connections
26 Creepage distances, clearances and distances
   through insulation
27 Resistance to heat, fire and tracking
28 Resistance to rusting
Annexes
Annex C - Creepage distances (cr), clearances (cl)
          and distances through insulation (dti)
          Material group II (400 <= CTI < 600)
Annex D - Creepage distances (cr), clearances (cl)
          and distances through insulation (dti)
          Material group I (CTI >= 600)
Annex R - Explanations of the application of 4.2 of
          IEC 60664-1:2007
Bibliography
Annex ZA (normative) - Normative references to
         international publications with their
         corresponding European publications

Specifies the safety of safety isolating transformers for general applications and power supply units incorporating safety isolating transformers for general applications. Transformers incorporating electronic circuits are also covered by this standard.

Replacement:

This part of IEC 61558 deals with the safety of safety isolating transformers for general applications and power supply units incorporating safety isolating transformers for general applications. Transformers incorporating electronic circuits are also covered by this standard.

NOTE 1 Safety includes electrical, thermal and mechanical aspects.

Unless otherwise specified, from here onward, the term transformer covers safety isolating transformers for general applications and power supply units incorporating safety isolating transformers for general applications.

NOTE 2 For power supply units (linear) this part is applicable. For switch mode power supply units, IEC 61558-2-16 is applicable together with this part.

This part is applicable to stationary or portable, single-phase or polyphase, air-cooled (natural or forced) independent or associated dry- type transformers. The windings may be encapsulated or non-encapsulated.

The rated supply voltage does not exceed 1 100 V a.c., and the rated supply frequency and the internal operating frequencies do not exceed 500 Hz.

The rated output does not exceed:

• 10 kVA for single-phase transformers;

• 16 kVA for polyphase transformers.

This part is applicable to transformers without limitation of the rated output subject to an agreement between the purchaser and the manufacturer.

NOTE 3 Transformers intended to supply distribution networks are not included in the scope.

The no-load output voltage or the rated output voltage does not exceed 50 V a.c. or 120 V ripple-free d.c.

This part is not applicable to external circuits and their components intended to be connected to the input terminals and output terminals of the transformers.

Transformers covered by this part are used in applications where double or reinforced insulation between circuits is required by the installation rules or by the end product standard.

NOTE 4 Attention is drawn to the following:

• for transformers intended to be used in vehicles, on board ships, and aircraft, additional requirements (from other applicable standards, national rules, etc.) may be necessary;

• measures to protect the enclosure and the components inside the enclosure against external influences such as fungus, vermin, termites, solar-radiation, and icing should also be considered;

• the different conditions for transportation, storage, and operation of the transformers should also be considered;

• additional requirements in accordance with other appropriate standards and national rules may be applicable to transformers intended for use in special environments.

NOTE 5 Future technological development of transformers may necessitate a need to increase the upper limit of the frequencies, until then this part may be used as a guidance document.