A 150 hp, 200 V, 1,500 rpm shunt dc motor with compensating windings has an armature resistance (which includes the brushes, compensating windings, and inter-poles) of 0.04 V. Its field circuit has a total Rajus + RF resistance of 60 V, which produces a no-load speed of 1,500 rpm. There are 2000 turns per pole in the shunt field winding.

Construct the motor speed torque curve (in the full range) 

Assuming ideal conditions and that you can manipulate the variable field resistance to modify the field current, repeat the exercise with two new values of Rajus that is (16)% higher and lower than the original Rajus

Plot the new curves and compare . What can you conclude? 

Hint: Plot all three curves on one graph and compare their slopes. See if they cut at any point and what that cut point means.

Answer rating: 100% (QA)

To construct the speedtorque curve for the given motor we can use the following formula T V IaRa IfRf K w where T is the torque V is the applied voltage Ia is the armature current Ra is the armature r... View the full answer