Kompensation, Blindleistung, Leistungsdreieck

This video explains compensation using phasor diagrams and the power triangle of a motor. Why is compensation necessary? And how is it performed? More about capacitors? :    • Der "gemeine" Kondensator im Gleichstromkreis   More about phase shift and phasors?:    • Phasenverschiebung, Einheitskreis, Wechsel...