muuntokykyä

Muuntokyky, or transformer capacity, refers to the maximum electric power that a transformer can safely transfer from primary to secondary winding. It is usually expressed in kilovolt–amperes (kVA) or megavolt–amperes (MVA). This rating is determined by factors such as core size, winding geometry, conductor material, insulation class, cooling method, and ambient temperature. The capacity is calculated from the transformer's rated voltage levels and the available short-circuit current and is limited by thermal and magnetic considerations.

Transformer capacity is crucial in power system design because it dictates how much load can be connected without exceeding the device's thermal limits. Overloading a transformer causes excessive copper or core losses, leading to overheating, insulation degradation, and eventual failure. Therefore, equipment specifications list the muuntokyky to guide engineers in selecting the right transformer for a given application.

In practice, operators use muuntokyky to size protection settings and to plan for contingencies such as fault currents or future load growth. In grid-scale systems, the rating informs voltage regulation, power factor correction, and stability analysis. Because electrical engineering standards vary worldwide, the same transformer may have different capacity values under different testing conditions, and conversion factors may be applied when comparing international specifications.