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适用范围：Replacement:This part of IEC 61558 deals with safety aspects of control transformers and power suppliesincorporating control transformers such as electrical, thermal and mechanical safety.This Part 2-2 is applicable to control transformers and power supplies incorporating bothcontrol transformers and electronic circuits. This Part 2-2 is not applicable to externalcircuits and their components intended to be connected to the input terminals, output terminalsor socket-outlets of the transformer and power supplies.This Part 2-2 does not apply to transformers covered by IEC 60076-11.This Part 2-2 applies to stationary or portable, single-phase or poly-phase, air-cooled (naturalor forced), independent or associated control transformers and power suppliesincorporating a control transformer, having a rated supply voltage not exceeding 1 000 Va.c. and rated supply and internal operating frequency not exceeding 500 Hz.The rated thermal output does not exceed:– 25 kVA for single-phase control transformers and power supplies incorporating controltransformers;– 40 kVA for poly-phase control transformers and power supplies incorporating controltransformers.This Part 2-2 is applicable to control transformers and power supplies incorporating controltransformers without limitation of the rated output subject to an agreement between thepurchaser and the manufacturer.This Part 2-2 is applicable to dry-type transformers. The windings may be encapsulated ornon-encapsulated.The no-load output voltage or the rated output voltage does not exceed 1 000 V a.c. or1 415 V ripple-free d.c.For independent control transformers and independent power supplies incorporatingcontrol transformers, the no-load output voltage and / or the rated output voltage is notless than 50 V a.c., or 120 V ripple free d.c.Control transformers covered by this Part 2-2 are used only in applications where double orreinforced insulation between circuits is not required by the installation rules or by the endproduct standard.NOTE 1 Normally, the control transformers and power supplies incorporating control transformers areintended to be used with equipment to provide voltages different from the supply voltage for the functionalrequirements of the equipment. The protection against electric shock may be provided (or completed) by otherfeatures of the equipment, such as the body. Parts of output circuits may be connected to the input circuits or toprotective earth.This Part 2-2 is applicable to control transformers and power supplies incorporating controltransformers associated with specific equipment, to the extent decided upon by the relevantIEC technical committees.NOTE 2 Attention is drawn to the following:– for control transformers and power supplies incorporating control transformers intended to be used invehicles, on board ships and on board 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 suchas fungus, vermin, termites, solar-radiation, and icing should also be considered ;– the different conditions for transportation, storage, and operation of the control transformers and powersupplies incorporating control transformers should also be considered;– additional requirements in accordance with other appropriate standards and national rules may be applicable tocontrol transformers and power supplies incorporating control transformers intended for use in specialenvironments, such as tropical environments.NOTE 3 Future technological development of control transformers and power supplies incorporating controltransformers may necessitate a need to increase the upper limit of the frequencies, until then this Part 2-2 may beused as a guidance document.