D.C. Motors

According to Fleming’s left-hand rule, when the forefinger points in the direction of the field or flux, the middle finger will point in the direction of_________________?

A. current in the conductor aovtaat of conductor
C. resultant force on conductor
D. none of the above

Which D.C. motor is preferred for elevators ?

A. Shunt motor
B. Series motor
C. Differential compound motor
D. Cumulative compound motor

Differentially compound D.C. motors can find applications requiring___________?

A. high starting torque
B. low starting torque
C. variable speed
D. frequent on-off cycles

Which D.C. motor will be preferred for machine tools ?

A. Series motor
B. Shunt motor
C. Cumulative compound motor
D. Differential compound motor

If a D.C. motor is to be selected for conveyors, which rriotor would be preferred ?

A. Series motor
B. Shunt motor
C. Differentially compound motor
D. Cumulative compound motor

Which of the following application requires high starting torque ?

A. Lathe machine
B. Centrifugal pump
C. Locomotive
D. Air blower

The direction of rotation of a D.C. series motor can be changed by___________?

A. interchanging supply terminals
B. interchanging field terminals
C. either of A. and B. above
D. None of the above

No-load speed of which of the following motor will be highest ?

A. Shunt motor
B. Series motor
C. Cumulative compound motor
D. Differentiate compound motor

A. 20 nm
B. 200 nm
C. 250 nm
D. 300 nm

A. Prokaryotic organisms
B. Unicellular organisms
C. Fungi
D. Eu-cariotiquic organisms