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.
Types of cells and batteries are:- a. Carbon-zinc cell b. Nickel-cadmium cell c. Alkaline celld. d. Edison cell e. Mercury cell
Fields Winding It produces the working flux, this is also called exciting winding.
Hysteresis results in a dissipation of energy Hysteresis results in a dissipation of energy which appears as a heating of the magnetic material. The energy loss associated wit
explane the special features of dual beam?
Explain the Third Group of 32 ASCII Character? The third group of 32 ASCII characters is set aside for the upper case alphabetic characters. The ASCII codes for the characters
An ice plant produces 12tonn of ice per day at 0 0 C using water at 300C. The plant operates on reversed Carnot cycle between -15 0 C and 28 0 C. If the actual C.O.P. is 50% of the
Bivector Meter As it is clear from the name provided 'Bivector', it records kWh and kVAh consumption along with maximum demand on both or on any one as needed. The working pri
What are the advantages of distributing windings in an alternator?
Q. What do you understand by common control? In some switching systems, control subsystem may be an integral part of switching network itself. Such system iscalled direct contr
Q. Why is an emitter bypass capacitor used in an RC coupled amplifier? If an emitter resistor Re is used for self-bias in an amplifier and if it is desired to avoid the degene
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