What is rated capacity?

Rated capacity refers to the conventional value of apparent power below the main tap. The capacity specified on the transformer nameplate is the rated capacity, representing the situation when the tap switch is at the main tap, i.e., the product of rated no-load voltage, rated current, and the corresponding phase factor. For three-phase transformers, the rated capacity is equal to √3 times the rated no-load line voltage times the rated line current, usually expressed in kVA or MVA. The rated capacity is the maximum capacity that can be continuously outputted throughout the specified entire normal service life, such as 30 years. The actual output capacity depends on the voltage under load (in the case of inductive load, the voltage under load is less than the rated no-load voltage), rated current, and the corresponding phase factor.

For no-load voltage-regulating transformers, the rated capacity can be outputted when the tap position is at -5%, and the rated output capacity needs to be reduced when the tap position is below -5%. For on-load voltage-regulating transformers, manufacturers typically specify that the rated capacity can still be outputted at the -10% tap position, while the rated output capacity needs to be reduced when the tap position is below -10%.

The above content mainly pertains to constant magnetic flux voltage-regulating power transformers or distribution transformers. For variable magnetic flux voltage-regulating electric furnace transformers or rectifier transformers, the rated capacity represents the maximum output capacity, but in most tap positions, the output capacity is less than the rated capacity.

Know more about power transformer and reactor:www.lstransformer.com