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an audio-frequency ideal transformer is employed to couple a 60-omega resistance load to an electric source which is
two transformers each rated 250-kva 112-kv and 50-hz are connected in opendelta on both the primary and secondarya find
an ideal 3-phase step-down transformer connected deltastar delivers power to a balanced 3-phase load of 120 kva at 08
1 what is a transformer explain the functions it fulfils as an element of a power system2 differentiate between core
for the cylindrical iron-clad solenoid magnet of fig 49 assume that the magnetic path reluctance remains constant at a
1 a 6-pole wave-connected dc armature has 300 conductors and runs at 1200 rpm the emf generated is 600 v find the
1 phase a of a 3-phase stator at the instant of carrying maximum current has 60 amperesconductors in the phase belt
1 determine the breadth and pitch factors for a 3-phase winding with 2 slots per pole per phase the coil span is 5
1 define field energy and co-energy2 why do all practical energy conversion devices make use of the magnetic field as a
for the electromagnetic relay of fig 411 calculate the maximum force on armature if saturation flux density in the iron
a 3-phase induction motor runs at a speed of 940 rpm at full-load when supplied with power at 50 hz 3-phasea how many
1 what measures are adopted to make the b-wave in a synchronous machine nearly sinusoidal why should the b-wave be
1 in a distributed winding why is the phase emf less than the algebraic sum of phase current in series2 derive the
1 a 4-pole 3-phase synchronous motor fed from 50-hz mains is mechanically coupled to a 24-pole 3-phase synchronous
a 200 v shunt motor has ra 0 1 omega rf 240 omega and rotational loss 236 omega on fullload the line current is 98 a
a 220 v unsaturated shunt motor has an armature resistance including brushes and interpoles of 004 w and the field
a dc shunt motor is being operated from 300 v mains its no-load speed is 1200 rpm when fully loaded it delivers a
a 50 kw 230 v dc shunt motor has an armature resistance of 01 omega and a field resistance of 200 omega it runs on
a 15 kw 250 v 1200 rpm shunt motor has 4 poles 4 parallel armature paths and 900 armature conductors ra 02 omega at
a 20 kw 500 v shunt motor has an efficiency of 90 at full load the armature copperloss is 40 of the full-load loss the
a 115 kw 600 v dc series wound railway track motor has a combined field and armature resistance including brushes of
a 100 kw 600 v 600 rpm dc series wound railway motor has a combined field and armature resistance including brushes of
a 3 kw series motor runs normally at 800 rpm on a 240 v supply taking 16 a the field coils are all connected in series
a 600 v dc motor drives a 60 kw load at 900 rpm the shunt field resistance is 100 w and the armature resistance is 016
enumerate the principal losses that occur in a dc generator and where appropri ate state the general form of the