The equivalent circuit of a series-connected DC Motor is shown in Figure below. Assuming a linear relationship between magnetic flux and field current, ? = K _F I _F use the supplied equations, Kirchoff's voltage law applied to the equivalent circuit, and the assumption of steady-state conditions so that the voltage across the inductor is zero, to derive the following relationship between torque and speed:

Tar I KK,V, (R + R + KK,w) Armature LF RF RA 0000 in i 1A = Ip Field EA D Relevant Equations: EA = Kow Tder = Kl Pdev EAL a =Tev@=EAIA E120 42