DC Motors – Online Free Mock Test-1
Number of Questions – 40 MCQ’s
Notes : The Quiz makes In multiple-choice quiz, there is a timer for 50 seconds/question.When 10 seconds is left, automatically the timer is red in color.finally, when the time is end,the correct answer is automatically shown.
A DC motor is any of a class of rotary electrical motors that converts direct current (DC) electrical energy into mechanical energy. The most common types rely on the forces produced by magnetic fields. Nearly all types of DC motors have some internal mechanism, either electromechanical or electronic, to periodically change the direction of current in part of the motor.DC motors were the first form of motor widely used, as they could be powered from existing direct-current lighting power distribution systems. A DC motor’s speed can be controlled over a wide range, using either a variable supply voltage or by changing the strength of current in its field windings. Small DC motors are used in tools, toys, and appliances. The universal motor can operate on direct current but is a lightweight brushed motor used for portable power tools and appliances. Larger DC motors are currently used in propulsion of electric vehicles, elevator and hoists, and in drives for steel rolling mills. The advent of power electronics has made replacement of DC motors with AC motors possible in many applications. More Details visit https://en.wikipedia.org/wiki/DC_motor
- A D.C. series motor is that which
- What will happen if the back e.m.f. of a D.C. motor vanishes suddenly?
- Which of the following load normally needs starting torque more than the rated torque?
- Which one of the following is not the function of pole shoes in a D.C. machine?
- Speed control by Ward Leonard method gives uniform speed variation
- As there is no back e.m.f. at the instant of starting a D.C. motor, in order to prevent a heavy current from flowing though the armature circuit
- If the speed of a D.C. shunt motor is increased, the back e.m.f. of the motor will
- Torque developed by a D.C. motor depends upon
- D.C. generators are installed near the load centres to reduce
- Where D.C. motor of H.P. 12 or more requires frequent starting, stopping, reversing and speed control