A DC shunt motor takes 80KW input at a terminal voltage of 400 Volts and running at 620 rpm. The armature and shunt field resistances are 0.1 Ω and 50 Ω respectively. Determine the speed of the same machine when running as shunt generator and delivers an output of 80KW at 400 Volts. Consider the contact drop as 1 Volt per brush

A 250 V, 4-pole, wave-wound d.c. series motor has 782 conductors on its armature. It has armature and series field resistance of 0.75 ohm. The motor takes a current of 40 A. Estimate its speed and gross torque developed if it has a flux per pole of 25 mWb.

This course EHide blom Clear my choice An eight-pole, 24 KW, 124 V, DC machine has a duplex LAP-wound armature which has 72 coils with 6 turns per coil. Its rated speed is 3000 RPM. Assume no dead zone Find the constant K and the flux per pole to produce 80 Volts at no-load conditions Select one: a. None Ob. K = 68.86 and flux = 3.33 mWb/pole Oc.K = 68.755 and flux = 3.7 mWb / pole O d. K = 95.5 and flux = 3.7 mWb / pole A peries DC motor has a series-field windino of 25 turns per pole. Its armature resistance in 0,1 2. and its

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A DC series motor having a resistance of 0.4 ꭥ and runs at 2000 rpm when connected to 250 V supply and drawing a current of 20 A. (i) What resistance must be added in order to limit the speed to 4000 rpm when armature current is 5A? Assume flux varies linearly. (ii) What resistance must be added to limit the speed to 1000 rpm when armature current is 30 A? Assume that the flux at 30 A is 20% more than that at 20A. (iii) At what speed the motor will run if it is connected directly to 250 V supply when the load is such that the current drawn is 30 A?

A 600 V series motor takes 120 A and operates at 900 rpm when the load is80 HP. If the effective circuit resistance is 0.20 ohm, calculate the HPoutput of the motor when the current drops to 90 A. assuming that the fluxis reduced by 20 %. [Ans. 49.86 HP]