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.
Half-wave rectifier: A half-wave rectifier will just only give one peak per cycle and for this reason and other reasons is only employed in extremely small power supplies. A f
I have to make assignment of about the topic Magnetism and magnetic materials. I don''t know how I will prepare this assignment. Please give me some instructions about this.
advantages of constant current bias
A 3 phase 60 hertz induction motor has 8 poles and operates with a slip of .05 for a certain load. Compute in r.p.m. the (a)speed of the rotor with respect to the stator, (b)spe
cross magnetizing components of armature reaction is...........
A small signal amplifier circuit is given in figure Q 4. The values of RD and RS must be set such that the gain of the system is 8. It is also known that Vgs = ¼ Vp. a). Per
advantages of superposition theorem
(1) An argon ion laser, emitting light at a wavelength of 488nm with a beam divergence of 150 firad, is used to illuminate the moon. (i) Assuming the earth-to-moon distance is 3
Seal Management - Meter Field Testing For an effective seal management system it is necessary that: i) The seals used are tamper proof, that is they cannot be remo
A 3 phase 60 hertz induction motor has 8 poles and operates with a slip of .05 for a certain load. Compute in r.p.m. the (a) Speed of the rotor with respect to the stator, (b
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