Safety of Power Transformers, Power Supply Units and Similar Devices - Part 2-19: Particular Requirements for Perturbation Attenuation Transformers
|Publication Date:||1 June 2000|
|ICS Code (Transformers. Reactors):||29.180|
This International Standard deals with all aspects of safety such as electrical, thermal and mechanical.
This part 2-19 of IEC 61558 applies to stationary or portable, single-phase or poly-phase, aircooled (natural or forced), independent or associated, isolating or safety isolating transformers, having a rated supply voltage not exceeding 1 000 V a.c., a rated frequency not exceeding 500 Hz, a rated output not exceeding 10 kVA. Perturbation attenuation transformers are intended to the supply of office machines and the like and have a mid-point lead out in the output circuit in order to attenuate mains borne disturbances.
In addition, double or reinforced insulation between circuits required by the installation rules or by the appliance specification is fulfilled by using this transformer.
NOTE 1 Connection of an appliance via transformers of the kind referred to here does not imply that the requirements for this appliance are allowed to be less stringent.
Perturbation attenuation isolating transformers:
- have a no-load output voltage and a rated output voltage exceeding 50 V a.c. or 120 V ripple-free d.c. and not exceeding 500 V a.c. or 708 V ripple free d.c.; the no-load output voltage and the rated output voltage may exceed these limits in order to be in accordance with the national wiring rules or special purposes, however they shall not exceed 1 000 V a.c. or 1 415 V ripple free d.c.
Perturbation attenuation safety isolating transformers:
- have a no-load output voltage and a rated output voltage not exceeding 50 V a.c. or 120 V ripple-free d.c.
This standard is applicable to dry-type transformers. The windings may be encapsulated or non-encapsulated.
Where an isolating transformer provides supply to two or more items of equipment, a connection of exposed-conductive-p
NOTE 2 For transformers filled with liquid dielectric or pulverised material, such as sand, additional requirements are under consideration.
NOTE 3 Attention is drawn to the fact that:
- for transformers intended to be used in tropical countries, special requirements may be necessary;
- in locations where special environmental conditions prevail, particular requirements may be necessary.
NOTE 4 This part 2-19 does not prevent the use of other types of transformers as attenuation transformer without mid-point in the output circuit.
This standard does not cover the performances of the function "attenuation". This function may be obtained by different features, for example: screen or special lamination.
This standard also applies to transformers incorporating electronic circuits. This standard does not apply to external circuits and their components intended to be connected to the input and output terminals or socket-outlets of the transformer.