5.2 Explain how a rotating commutator winding may be represented as an equivalent pseudo-stationary coil along the brush axis, and describe the special properties of this type of coil. Write the general voltage and torque equations for the two-pole commutator machine shown in Fig. Prob. 5.2. Explain how the rotational inductance coefficients (G) may be obtained in terms of the Land 1 inductance coefficients. q-axis 9 Fig. Prob. 5.2 d-axis

A 500-turn coil is wound on an iron core. When a 120-V-rms 60-Hz voltage is applied to the coil, the current is 1 A rms. Neglect the resistance of the coil. Determine the reluctance of the core. Given that the cross-sectional area of the core is 5 cm2 and the length is 20 cm, determine the relative permeability of the core material.

Q9. What is the basic principle that a cage winding can be represented by a three-phase winding? Give your explanation.

A Cockcroft-Walton type voltage multiplier has ten stages with capacitances, all equal to 0.1 μF. The supply transformer secondary voltage is 100 kV at a frequency of 60 Hz. If the load current to be supplied is 5 mA, find (a) the percentage ripple, (b) the regulation, and (c) the optimum number of stages for minimum regulation or voltage drop.

I couldn't understand the solution provided by the previous expert because the writing was not clear.

Q.4/ choose true or false: 1. The reluctance of any core is proportional directly with the length of it and inversely with both the permeability and the cross-section area of it. 2. The number of parallel paths in wave windings is equal to twice of the number of poles. 3. In dc machines with same values of Z, N, Ø, the emf for wave winding type is more than emf of lab winding type. 4. If we insert a current in such a conductor subjected to a constant magnetic field, a movement will achieved giving the principle of electric generator.