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.
A 3-phase transmission line is 200km long. The line has a per phase series impedance of 0.25+j0.45 Ω/km and shunt admittance of j7.2 μS/km. The line delivers 250MVA, at 0.6 lagging
Q A beam containing two types of charged particles is moving from A to B. Particles of type I with charge +3q, and those of type II with charge -2q (where -q is the charge of an el
I´m looking for some help to identify some electronic parts, i have this led driver with preset dim levels that i can reach with switching the power on and off. The driver worked r
The winding of an electromagnet has an inductance of 3H and a resistance of 15?. When it is connected to a 120 V d.c. supply, Determine: (a) the steady state value of current f
Q. Explain phase-shift keying? In PSK, the phase angle of a carrier is keyed between two values. When the values are separated by π radians, it is known as phase-reversal keyin
find the resultant of two forces 20N and25N acting at an angle 60 degree each other
analysis and detail working of bootstrap sweep circuit
Explain Memory Mapped I/O Scheme. Memory Mapped I/O Scheme: In such scheme there is only one address space. These address space is defined as all possible addresses which m
Q. Which of the 3 transistor configuration is best to use in cascade if maximum voltage gain is to be realized? The common collector configuration is not used for intermediate
Q. Explain Working of Liquid-crystal display? This display needs only microwatts of power (over a thousand times less than a LED) and is used in such devices as electronic wris
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