I came across an equation for the Speed ω in Radians/seconds of a Cumulative Compound DC motor. ω= K(Vt-IA[RA+RF)/([itex]\Phi[/itex]P+[itex]\Phi[/itex]S) How would we calculate K in this equation? Shouldn't the Terminal Voltage Vt be replaced by Armature Voltage Ea? I came across a lot of varying torque speed curves. WIll the curve be exponentially decaying or linear?