Description

This Standard specifies general safety requirements for approval and test purposes.

This Standard is an adoption with national modifications and contains the full text of IEC 61558-1:1998.

Scope

This Standard deals with all aspects of safety (such as electrical, thermal and mechanical) of:

a) Stationary or portable, single-phase or polyphase, air-cooled (natural or forced) isolating and safety isolating transformers, associated or otherwise, having a rated supply voltage not exceeding 1 000 V a.c. and rated frequency not exceeding 1 MHz, the rated output not exceeding the following values.

For isolating transformers:

• 25 kVA for single-phase transformers;
• 40 kVA for polyphase transformers.

For safety isolating transformers:

• 10 kVA for single-phase transformers;
• 16 kVA for polyphase transformers.

The no-load output voltage and rated output voltage do not exceed:

• for isolating transformers 500 V a.c. or 708 V ripple free d.c.
• for safety isolating transformers 50 V a.c. r.m.s. and/or 120 V ripple free d.c. between conductors or between any conductor and earth.

Rated values for each type of transformer are indicated in the relevant part 2.

b) Stationary or portable, single-phase or polyphase, air-cooled (natural or forced) separating transformers, auto-transformers, variable transformers and small reactors, associated or not, having a rated supply voltage not exceeding 1 000 V a.c., a rated frequency not exceeding 1 MHz, a rated no-load or load output voltage not exceeding 15 kV a.c. or d.c., and for independent transformers not less than 50 V a.c. and/or 120 V ripple free d.c. and a rated output not exceeding the following values:

• 1 kVA for single-phase transformers;
• 2 kVAR for single-phase reactors;
• 5 kVA for polyphase transformers;
• 10 kVAR for polyphase reactors;

unless otherwise specified in the relevant part 2.

c) Power supply units incorporating a transformer of types a) or b). 

This standard is applicable to dry type transformers. The windings may be encapsulated or non-encapsulated.

This standard is also applicable to transformers associated with specific items of equipment, to the extent decided upon by the relevant IEC technical committees. Transformers incorporating electronic circuits are also covered by this standard.

This standard does not apply to external circuits and their components connected to terminals or socket-outlets of the transformer.