Basic Electrical Engineering

Three phase AC circuits   Topic AC Circuit Fundamentals Single phase AC Circuits Three phase AC circuits AC Circuit Problems Two alternating currents in a parallel circuit are represented by i_1=5 sin(omega)t and i_2=10 sin((omega)t +60 deg). Find the resultant current. The equation for an AC voltage is given as v=0.04sin(2000t+60 degree)V. Determine the frequency, the angular frequency, instantaneous voltage when t=160 micro sec. What is the time represented by a 60 degree phase angle. Given v=200 sin 377t volts…

Single phase AC Circuits   Topic AC Circuit Fundamentals Single phase AC Circuits Three phase AC circuits AC Circuit Problems Two alternating currents in a parallel circuit are represented by i_1=5 sin(omega)t and i_2=10 sin((omega)t +60 deg). Find the resultant current. The equation for an AC voltage is given as v=0.04sin(2000t+60 degree)V. Determine the frequency, the angular frequency, instantaneous voltage when t=160 micro sec. What is the time represented by a 60 degree phase angle. Given v=200 sin 377t volts…

AC Circuit Fundamentals Single phase AC Circuits Three phase AC circuits   Topic AC Circuit Fundamentals Single phase AC Circuits Three phase AC circuits AC Circuit Problems Two alternating currents in a parallel circuit are represented by i_1=5 sin(omega)t and i_2=10 sin((omega)t +60 deg). Find the resultant current. The equation for an AC voltage is given as v=0.04sin(2000t+60 degree)V. Determine the frequency, the angular frequency, instantaneous voltage when t=160 micro sec. What is the time represented by a 60 degree…

DC Motors Important terms and formulae for DC Motors, Back EMF induced in a DC Motor is given by the equation, Types of DC Motors, Important terms of DC Motors, Separately Excited DC Motors, Series DC Motors, Shunt DC Motors, Compound DC Motors - Long Shunt Compound Motor and Short Shunt Compound Motor, DC Motor Power calculating equation, DC Motor Torque equation, DC Motor Speed equation Topic DC Motors DC Motor Problems The field current in shunt DC machine is 2 A and the line current is 20 A…

DC Generators Important terms and formulae of DC Generators, EMF induced in a DC Generator is given by the equation, Types of DC Generators, Important terms of DC Generators, Separately Excited DC Generators, Series DC generators, Shunt DC generators, Compound DC generators - Long Shunt Compound generator, Short Shunt Compound generator Topic DC Generators DC Generators Problems A shunt generator has 4 poles lap wound armature having 24 slots with 10 conductors per slot. If the flux per pole is…

Electromagnetism Important Formulae Topic Electromagnetism Electromagnetism Problems An iron ring has a mean circumference of 50cm and a cross sectional area of 4cm^2 it is wound with 600 turns of wire if the μ_r of iron is 400. Calculate the inductance of the coil and the energy stored in the magnetic field if the current flowing through the coil is 10A A coil of 500 turns wound on a core of non-magnetic material (μ_r=1) has an inductance of 9mH. Calculate…

Induction Motor Important Formulae to remember Topic Induction Motor Induction Motor Problems The frequency of the EMF in the stator of a 4 pole induction motor is 50 Hz and in the rotor is 1.5 Hz. What is the slip and what speed is the motor running? A 3 ∅ induction motor with 4 poles is supplied from the alternator having 6 poles running at 1000 rpm. Calculate synchronous speed of the induction motor its speed when slip is 0.04…

Transformer Important formulae to remember Topic Transformer Examples The maximum efficiency at full load and unity power factor of a 1∅, 25 KVA, 50/1000V, 50Hz transformer is 98%. Determine the efficiency at (i) 75% load 0.9 p.f (ii) 50% load 0.9 p.f (iii) 25% load 0.6 p.f A 500KVA transformer has an efficiency of 92% at full load unity power factor and at half full load 0.9 p.f. Determine it’s efficiency at 80% full load and 0.95 p.f A 1∅,…

Alternators Important Formulae to remember Topic Alternators Examples A 12 pole 500 rpm, star connected alternator has slots with 15 conductors per slot. The flux per pole is 0.02 wb .The winding factor is 0.97 and pitch factor is 0.98. Calculate the phase EMF and line EMF A 3∅, 6 pole star connected alternator has an armature with 90 slots and 12 conductors per slot, it revolves at 1000 rpm, the flux per pole being 0.05 wb. Calculate the line…