In forward motoring operation of a DC Drive.................................. a. The back emf is greater than terminal voltage b. The back emf and terminal voltage are same c. The back emf opposes the terminal voltage d. The back emf is in same direction of terminal voltage

a) Which components determine the excitation current of a transformer? How are they in transformer equivalent circuit modeled? b) Why is the polarity determination of a transformer made? Briefly explain how the experiment is done. c) If the direction of rotation of the motor changes when the feeding ends are changed in a DC motor, what can be said about its type? d) Why does the peak voltage increase as the serial DC generator is loaded? How long does this increase continue?

Q4. (A)- Indicate whether the following statements are true or false and correct the false statements 1. The inter pole winding is connected in parallel to field winding. 2. The produced sparks at the brushes of a de machine is due to friction losses. 3. Series DC motors are used for low torque applications. 4. In series DC generator, Increasing the load current will decrease the magnitude of the generated voltage. 5. The compensation windings are place at the pole face and used to mitigate the effect of the armature reaction.

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Pls Explain the following  Contrast DC motor types withDC generator

A. The DC motor in Figure 1 on Worksheet 8 is a a) cumulatively connected short-shunt compound DC motor b) cumulatively connected long-shunt compound DC motor c) differentially connected short-shunt compound DC motor d) shunt DC motor B. The DC motor in Figure 2 on Worksheet 8 is a a) cumulatively connected short-shunt compound DC motor b) cumulatively connected long-shunt compound DC motor c) differentially connected short-shunt compound DC motor d) shunt DC motor

For a dc generator, the current of the shunt winding is small as compared to armature current true False

We make( V/F) constant in speed control of three-phase induction motor in order to make motor torque constant? * True False

g) What is an advantage if the starting Torque of the induction motor is higher than the nominal load Torque? h) What are the main differences when the equivalent circuits of transformer and asynchronous motor are examined?

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