Question

3. (25 points) Induction Motor Torque Production. An induction motor has the torque vs. speed curve shown below. By changing the machine's inputs or its parameters, we can influence its behavior. For example, cutting its terminal voltage by half yields the changes illustrated below Peak Torque at same speed t(slip) % of the Peak Torque Floalslip) Slightly reduced operating speed, but double the operating slip 2001000 100 200 slip) % of the Starting Torque We can influence its torque production by adding resistance, either to the stator or to the rotor Estimate and plot what you expect would be its torque vs. speed curve by doubling the stator resistance and, separately, by doubling the rotor resistance, drawing and labeling the changes. Appropriate torque vs. speed curves and work space are provided on the next two pages Case 1: Double the Stator Resistance 60 40 t(slip) τ load(slip) 20 -200 100 -100 200 or(slip) Case 2: Double the Rotor Resistance 600 40 t (slip) τ load( slip) 20 200 0 -200 100 -100 orslip)

Answer 1

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