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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.
Q. What do you eman by Digital Circuits? The use of nonlinear devices (BJT and FET) in constructing linear amplifiers. Although these devices are inherently nonlinear, their op
(a) Design a passive high pass filter that has a maximally flat response with a 50 Ω resistive load. Assume that the cut-off frequency is 40 kHz and that at a frequency of 25 kHz,
purpose of equalizer rings in lap winding
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Based upon the following inputs, propose the optimal course of action for this venture: Probability of success: 30%; probability of failure: 30%; base case probability: 40%
i want to prodused domestic power factor correction like industial
Q. What do you mean by Negative Clamper? During the positive half cycle the diode conducts and acts like a short circuit. The capacitor charges to peak value of input voltage V
Electrical energy If the power is measured in watts and the time in seconds then the unit of energy is watt- seconds or Joules.
We commissioned a 'bad practice exemplar' by asking Plexus to modify a good design (provided by Valor) to demonstrate the most likely kinds of faults in each of the areas Design fo
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