MMF of AC Distributed Winding: It has been seen earlier that the armature what-when-how.comof a practical machine has distributed winding wound for the same number of poles as the field winding. As the armature carries current, the resultant field of its current-carrying coils has the same number of poles as the field winding. Our approach […]
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Electrical Braking of Polyphase Induction Motors: Electrical Braking of Polyphase Induction Motors which consists of different types, namely, Plugging (or Counter-Current Braking) Dynamic (or Rheostatic) Braking Regenerative Braking 1. Plugging (or Counter-Current Braking) Plugging can be achieved in an induction motor merely by reversing two of the three phases which causes a reversal of the
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Speed Control of Single Phase Induction Motor: The stator winding of a speed control of single phase induction motor can easily be arranged to give two synchronous speeds, one double the other. In Fig. 1.88 (a) the connections for two pole motors are shown in which two coils A and B have been connected in
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Field Diverter Method of Speed Control of DC Series Motors: The field flux can be reduced by shunting a portion of motor current around the series field, thus reducing the excitation mmf and weakening of field. This Field Diverter Method of Speed Control of DC Series Motors is illustrated in Fig. 1.72 (a). This method
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Amplidyne (Rotary Amplifier) – Definition, Construction, Connection Diagram, Workings and Applications: The amplidyne is a rotary amplifier in which a small amount of power supplied to excite the field is amplified in the generator output. Though the ordinary separately excited generator operated at low flux densities can be used as a power amplifier since the
Parallel Magnetic Circuit: We have seen that a series magnetic circuit carries the same flux and the total mmf required to produce a given quantity of flux is the sum of the mmf’ s for the separate parts. In a Parallel Magnetic Circuit, different parts of the circuit are in parallel. For such circuits the
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Difference Between Electric Circuit and Magnetic Circuit: A Difference Between Electric Circuit and Magnetic Circuit are shown in Figs. 10.27(a) and (b) respectively. Figure 10.27(a) represents an electric circuit with three resistances connected in series, the dc source E drives the current I through all the three resistances whose voltage drops are V1,V2 and V3. Hence,
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Series Magnetic Circuit: A series magnetic circuit is analogous to a series electric circuit. Kirchhoff s laws are applicable to magnetic circuits also. Consider a ring specimen having a magnetic path of l meters, area of cross-section (A)m2 with a mean radius of R meters having a coil of N turns carrying I amperes wound
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Magnetic Circuit Analysis: Magnetic Circuit Analysis – The presence of charges in space or in a medium creates an electric field, similarly the flow of current in a conductor sets up a magnetic field. Electric field is represented by electric flux lines, magnetic flux lines are used to describe the magnetic field. The path of
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Self Controlled Synchronous Motor Drive: A Self Controlled Synchronous Motor Drive employing a load commutated thyristor inverter is shown in Fig. 7.10. In large power drives wound field synchronous motor is used. Medium power drives also employ permanent magnet synchronous motor. The drive employs two converters, which are termed here as source side converter and
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