you are given a motor operated by a 9V battery....

Question

For all the questions below, you are given a motor operated by a 9V battery. The stall torque for this motor is Ts = 0.04 N-m, and its no-load speed, wnl = 2200 rpm.

1. Draw the torque vs. speed curve for this motor. Label the axes with names and units. Mark the no-load speed and the stall torque on the curve with appropriate numbers and units.

2. If this motor's shaft is spinning at a speed of 1100 rpm, what must be the torque provided by the motor shaft? (Hint: Use the torque vs. speed curve, or its equation)

Answer 1

Since electric motors have a straight straight line for their rpm vs torque curve,

1. simply draw a graph with 2200 rpm at the extreme end for one axis and 0.04 N-m for the other. Connect those two points with a straight line
2. half of 2200 is 1100, so the torque would be (1-1/2=1/2) half the stall torque, 0.02 N-m