The nature of [[magnetic flux]] makes it inevitable that part of itthe flux deviates from the intended "useful" path. In most designs, the productive flux links the rotor and stator; the flux that links just the stator (or the rotor) to itself is useless for energy conversion and thus is considered to be wasted [[leakage flux]] (''stray flux''). The corresponding inductance is called ''leakage inductance''. Due to the presence of [[Air gap (magnetic)|air gap]], the role of the leakage flux is more important in a synchronous machine in comparison to a [[transformer]]. {{sfn|Lipo|2017|p=67}}
