K-factor
The oversizing of a transformer intended for harmonic loads.
Definition
The K-factor is a standardised index that characterises a transformer’s ability to supply harmonic-generating loads without overheating. A “K1” transformer is intended for a classic linear load; a “K4”, “K13” or “K20” is reinforced to handle harmonic-rich currents.
High-order harmonics cause additional losses, notably through the skin effect and eddy currents in the windings. A high-K-factor transformer compensates for this with oversized conductors and neutral, shields and an adapted thermal design.
It is essential in data centres, installations with drives, or with massive LED lighting.
The ABL tip
Rather than oversizing “just in case”, the K-factor provides a calibrated response to polluting loads. Describe your equipment: we determine the K-factor just necessary to make your installation reliable without needless extra cost.
