Page 1 DC GENERATORS There are four major types of DC generators, namely ? Separately excited generator . ? Shunt generator . ? Series generator ? Compounded generator ? Cumulative ? Differential Page 2 DC GENERATORS There are four major types of DC generators, namely ? Separately excited generator . ? Shunt generator . ? Series generator ? Compounded generator ? Cumulative ? Differential The Equivalent Circuit of a DC Generator Two circuits are involved in DC generators Armature Circuit Field circuit ? Armature circuit represents Thevenin equivalent of the entire rotor. ? It cantain an ideal voltage source EA and a resistor RA. . ? Brush voltage drop is represented by a small battery ? The field coils, which produce the magnetic flux ? inductor LF and resistor RF ? Radj for field current control Page 3 DC GENERATORS There are four major types of DC generators, namely ? Separately excited generator . ? Shunt generator . ? Series generator ? Compounded generator ? Cumulative ? Differential The Equivalent Circuit of a DC Generator Two circuits are involved in DC generators Armature Circuit Field circuit ? Armature circuit represents Thevenin equivalent of the entire rotor. ? It cantain an ideal voltage source EA and a resistor RA. . ? Brush voltage drop is represented by a small battery ? The field coils, which produce the magnetic flux ? inductor LF and resistor RF ? Radj for field current control Magnetizing curve of a DC Generator & performance ? The internal generated voltage EA of a dc generator is given by ? EA is directly proportional to the flux ? The field current is directly proportional to the magnetomotive force and hence EA ? Brush voltage drop is represented by a small battery ? Performance of the DC generators are determined by terminal output parameter IL and VT ? V oltage regulation also determines its performance Page 4 DC GENERATORS There are four major types of DC generators, namely ? Separately excited generator . ? Shunt generator . ? Series generator ? Compounded generator ? Cumulative ? Differential The Equivalent Circuit of a DC Generator Two circuits are involved in DC generators Armature Circuit Field circuit ? Armature circuit represents Thevenin equivalent of the entire rotor. ? It cantain an ideal voltage source EA and a resistor RA. . ? Brush voltage drop is represented by a small battery ? The field coils, which produce the magnetic flux ? inductor LF and resistor RF ? Radj for field current control Magnetizing curve of a DC Generator & performance ? The internal generated voltage EA of a dc generator is given by ? EA is directly proportional to the flux ? The field current is directly proportional to the magnetomotive force and hence EA ? Brush voltage drop is represented by a small battery ? Performance of the DC generators are determined by terminal output parameter IL and VT ? V oltage regulation also determines its performance The Separately Excited Generator ? A separately excited dc generator is a generator whose field current is supplied by a separate external dc voltage source. ? By Kirchhoff's voltage law , the terminal voltage is ? Since the internal generated voltage is independent of lA the terminal characteristic of the separately excited generator is a straight line A separately excited dc generator The terminal characteristic (a) with and (b) without compensating windings Page 5 DC GENERATORS There are four major types of DC generators, namely ? Separately excited generator . ? Shunt generator . ? Series generator ? Compounded generator ? Cumulative ? Differential The Equivalent Circuit of a DC Generator Two circuits are involved in DC generators Armature Circuit Field circuit ? Armature circuit represents Thevenin equivalent of the entire rotor. ? It cantain an ideal voltage source EA and a resistor RA. . ? Brush voltage drop is represented by a small battery ? The field coils, which produce the magnetic flux ? inductor LF and resistor RF ? Radj for field current control Magnetizing curve of a DC Generator & performance ? The internal generated voltage EA of a dc generator is given by ? EA is directly proportional to the flux ? The field current is directly proportional to the magnetomotive force and hence EA ? Brush voltage drop is represented by a small battery ? Performance of the DC generators are determined by terminal output parameter IL and VT ? V oltage regulation also determines its performance The Separately Excited Generator ? A separately excited dc generator is a generator whose field current is supplied by a separate external dc voltage source. ? By Kirchhoff's voltage law , the terminal voltage is ? Since the internal generated voltage is independent of lA the terminal characteristic of the separately excited generator is a straight line A separately excited dc generator The terminal characteristic (a) with and (b) without compensating windings The Separately Excited Generator Control of T erminal V oltage > two methods ? Change the speed of rotation ? E A = K ??? >VT = EA ?-l A R A > VT ? ? Change the field current. ? I F = VF/R F ? > I F ? > ??> E A = K ??? > ? V T = E A ?-l A R A >VT ? The terminal characteristic (a) with and (b) without compensating windingsRead More

Offer running on EduRev: __Apply code STAYHOME200__ to get INR 200 off on our premium plan EduRev Infinity!

61 docs|20 tests