एक DC मशीन में कम्यूटेशन (commutation) का उद्देश्य क्या है?

In a DC motor, which of the following is the contributor to the difference between the shaft torque and the armature torque?

In DC machines, which of the following statements are correct? A. Reactance voltage is proportional to armature current. B. Reactance voltage is proportional to core length. C. Reactance voltage is due to self-flux of the coil undergoing commutation. D. Armature-cross flux is neutralized by interpolar flux. E. Interpolar MMF is more than the armature MMF in the Interpolar Zone. Choose the correct answer from the options given below:

A 220 V DC motor having an armature resistance of 0.8 Ω draws an armature current of 25 A. What is the value of the induced back EMF?

In a DC motor, what is the relationship between speed and back electromotive force (EMF), assuming constant flux?

In D.C. machines: A. Reactance voltage is proportional to armature current B. Reactance voltage is proportional to core length C. Reactance voltage is due to self-flux of the coil undergoing commutation D. Armature-cross flux is neutralized by interpolar flux E. Interpolar MMF is more than the armature MMF in the Interpolar Zone Choose the correct answer from the options given below: