Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
In the conventional dc machine (with a closed continuous commutator winding on its armature), for example, full-wave rectification of the alternating voltage induced in individual armature coils is achieved by means of a commutator, which makes a unidirectional voltage available to the external circuit through the stationary carbon brushes held against the commutator surface.The armaturewindings of dcmachines are located on the rotor because of this necessity for commutation and are of the closed continuous type, known as lap and wavewindings. The simplex lap winding has as many parallel paths as there are poles, whereas the simplex wave winding always has two parallel paths. The winding connected to the commutator, called the commutator winding, can be viewed as a pseudostationary winding because it produces a stationary flux when carrying a direct current, as a stationarywindingwould. The direction of the flux axis is determined by the position of the brushes. In a conventional dc machine, in fact, the flux axis corresponds to the brush axis (the line joining the two brushes). The brushes are located so that commutation (i.e., reversal of current in the commutated coil) occurs when the coil sides are in the neutral zone, midway between the field poles. The axis of the armature mmf is then in the quadrature axis, whereas the stator mmf acts in the field (or direct) axis. Figure shows schematic representations of a dc machine. The commutator is thus a device for changing the connections between a rotating closed winding and an external circuit at the instants when the individual coil-generated voltages reverse. In a dc machine, then, this arrangement enables a constant and unidirectional output voltage. The armature mmf axis is fixed in space because of the switching action of the commutator (even though the closed armature winding on the rotor is rotating), so the commutator winding becomes pseudostationary.
Why are the operating voltages of a CRT arranged so that the deflection plates are nearly at ground potential?
Q. Common-Emitter Configuration? The emitter part of a circuit being common to both the input and the output portions, Figure (a) illustrates a common-emitter (CE) BJT amplifie
Question: a). Draw the energy diagram of a pn junction: (i) at thermal equilibrium, (ii) when a forward bias with magnitude half the built in potential (V = φk/2) is applie
Write discussion on Construction and working of analog type storage oscilloscope
WHAT IS DRIFT
Impurities in Semiconductors Can be added in accurately controlled amounts. Can modify the electronic and optical properties. Used to change conductivity over wide ra
Binary Multiplication Multiplication can be seen as multiple additions. For example if we have to multiple 4 and 8 we can 8, 4 time to get the solution. Actually this conc
Question: Figure shows the basic circuit of the BJT Common Emitter Amplifier. (a) What is the function of RB, RC, Ci, Co and CE ? (b) (i) Sketch the d.c. equivalent circu
Define Series VAr Compensation? For very long transmission lines, the inductive reactance of the line becomes so high that not much power can be transmitted through the line, s
Using the LM741operational amplifier build a voltage amplifier with the voltage gain of |A V | = 500 v/v ± = 20%. Measure all necessary parameters of the amplifier (as per deliver
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd