Practical values of power factor

Average power factor values for the most commonly-used equipment and appliances

(see Fig. L7)

Equipment and appliances				cos φ	tan φ
Motor	Common induction motor	loaded at	0 %	0.17	5.80
			25%	0.55	1.52
			50 %	0.73	0.94
			75 %	0.80	0.75
			100 %	0.85	0.62
Lamps	Incandescent lamps			1.0	0
	Fluorescent lamps (uncompensated)			0.5	1.73
	Fluorescent lamps (compensated)			0.93	0.39
	Discharge lamps			0.4 to 0.6	2.29 to 1.33
Ovens	Ovens using resistance elements			1.0	0
	Induction heating ovens (compensated)			0.85	0.62
	Dielectric type heating ovens			0.85	0.62
Welding	Resistance-type soldering machines			0.8 to 0.9	0.75 to 0.48
	Fixed 1-phase arc-welding set			0.5	1.73
	Arc-welding motor-generating set			0.7 to 0.9	1.02 to 0.48
	Arc-welding transformer-rectifier set			0.7 to 0.8	1.02 to 0.75
Arc furnace				0.8	0.75

Fig. L7 – Values of cos φ and tan φ for commonly-used equipment