Hi, I'm attempting to make a model of a DC motor capable of calculating the efficiency of the motor for different values for torque. I have managed to make a code to generate the torque-speed-power plots for given inputs, however I have been unable to figure out how to calculate the efficiency at different points along the graph. I know that generally speaking there maximum efficiency is roughly 20-30% of the stall torque and 70-80% of the no load speed. But is there any specific formulae for this? I am also aware there are many different things affecting the efficiency so this may not be so simple. Thanks for any help!