2-1 Discuss different types of DC motor, Draw equivalent circuit and Torque speed characteristics for all.

A lap-winding DC machine has 24 coils, 18 turns per coil, and 4 poles. The average flux density per pole is 1T. The effective length is 40 cm and the armature radius is 10 cm. The armature velocity is 140.2 rad/sec and the armature current is 24 A. The average flux per pole in Wb is: 6.283 0.06283 O 0.6283 0.006283

6- Which of the following supply is given to the rotor winding of 3-Phase Induction Motor: a) DC Supply b) AC Supply c) No Supply d) Pulsating Supply 7- 3-Phase Induction Motor will have Starting Torque and Starting Current a) High, High b) Low, Low. c) High, Low d) Low, High 8- Which of the following method is used for controlling the speed of an induction motor: a) Changing number of stator poles b) Supply voltage control c) Frequency control d) All the options are correct 9- Which of the following method cannot be used for starting of 3-Phase Squirrel Induction Motor: a) Star-Delta Starting b) Line resistor startling c) transformer Starter d) Rotor Resistance Starting 10- The rotor of a stepper motor has no: a) windings b) commutator c) brushes d) all of the above

A value of magnetizing current in a 3-phase induction motor * gives power factor smaller .. larger smaller. .poor large . better O large...poor O

Here it is the equivalent circuit of and induction motor and it is per phase circuit my question is name for me the variable for example R1 is the winding resistance and so an the all variable and please show me a pic of the real machine with the variable for example for R1 happens because of the winding i need to see the winding in the real machine, please help me to understand well

A 240 V series motor develops a torque of 120 Nm at a speed of 900 rpm. The armature winding resistance is 0.20 and the series field winding resistance is 0.1 Q. For a constant load torque find the new speed of the motor when a diverter resistance of 0.1 Q is placed across the series field winding.

True or fulse

pole. 50-Hz. 3-ϕ induction motor has a full-load speed of 950 rpm. At half load its speed would be ..... rpm a) 475 b) 500 c) 975 d)1000

State two ways by which the output polarity of a shunt DC generator can be changed.

A 3-0, 50-Hz induction motor with its rotor star-connected gives 500 V (r.m.s.) at standstill between slip-rings on open circuit. Calculate the current and power factor in each phase of the rotor windings at standstill when joined to a star-connected circuit, each limb of which has a resistance of 10 Q and an inductance of 0.03 H. The resistance per phase of the rotor windings is 0.2 Q and inductance 0.03 H. Calculate also the current and power factor in each rotor phase when the rings are short- circuited and the motor is running with a slip of 4 per cent. [13.6 A, 0.48; 27.0 A, 0.47] (London University) A 4-pole, 50-Hz, 3-phase induction motor has a slip-ring rotor with a resistance and standstill reactance of 0.04 2 and 0.2 2 per phase respectively. Find the amount of resistance to be inserted in each rotor phase to obtain full-load torque at starting. What will be the approximate power factor in the rotor at this instant ? The slip at full-load is 3 per cent. [0.084 2, 0.516 p.f.]…