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 400V 4-pole DC generator takes an armature current of 50A when rotating at 626 rpm. the armature circuit resistance is 0,25ohms. determine the generated emf. DOC
Consider a GLC parallel circuit excited by i(t) = Ie st in the time domain. Assume no initial inductive current or capacitive voltage at t = 0. Draw the transformed network in the
Electric circuits or networks are formed by interconnecting various devices, sources, and components. Although the effects of each element (such as heating effects, electric-?eld e
Q. Based on the 8421 BCD code for decimal digits 0 through 9, develop a block diagram for a BCD encoder and its implementation scheme.
Q. Briefly explain about Laplace transform? Many commonly encountered excitations can be represented by exponential functions. The differential equations describing the network
a. Given a timer with a terminal count and a clock frequency of 10 MHz measure the following: (i) Range & Resolution (ii) Terminal count values needed to measure 3ms interval
Estimate the software tasks required for developing the product. These are likely to include the development of various software routines, associated documentation and verification
A multimode step index fibre along with a core diameter of 80µm and a associative refractive index difference of 1.5% is operating at a wavelength of 0.85µm. If the core refractive
12. A capacitor is to be constructed so that its capacitance is 0.2µF and to take a p.d. of 1.25kV across its terminals. The dielectric is to be mica which, after allowing a safety
Assuming that the receiver sends a XOFF signal when the receive buffer is P% full in order to avoid any data or packet loss.
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