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Title: How do you calculate output power in an AC Three phase Induction Motor? Post by: rkbrookover on Sep 6, 2012 Load=0.5Nm
input voltage=397V Amps= 1.77 Power Factor=0.66 Input Power= 762 Watts Speed= 1422rev per min or 148.91 rad per min these are all the values i have if that was correct then the power out would be greater than the power in which is impossible Title: How do you calculate output power in an AC Three phase Induction Motor? Post by: Juliehansen on Sep 6, 2012 P=IE
Title: How do you calculate output power in an AC Three phase Induction Motor? Post by: irina on Sep 6, 2012 in three phase circuit
input power is P=V*I*sqrt(3) output power is P=V*I*sqrt(3)*cos(theta) V=voltage (effective voltage) I=current (RMS current) sqrt(3) = 1.73.... (square root of three) cos(theta) = power factor based on given voltage and current values, input power is 1215W while output power is 802W we can also calculate same using mechanics: P=T*w where T is torque and w is angular velocity (rad/sec) 1422RPM is 149 rad/sec and with only 0.5Nm torque power is only 75W so your numbers don't match. are you reading current and voltage of the name plate or those are actual measurements? if the load is smaller, motor will draw less current (less than FLA listed on name plate). Title: How do you calculate output power in an AC Three phase Induction Motor? Post by: Lexyz on Sep 6, 2012 Output power = 1.732(397)(1.77)(0.66)
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