Author Archives: Changiz Rashidzadeh

Doubly-Excited Machines (Nature of Inductance Changes)

Machines with One Winding on the Stator and One winding on the Rotor The majority of electrical machinery that constitute the backbone of the industry (synchronous generators, induction motors and DC machines) belong to this group. In this kind of … Continue reading

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Singly-Excited Machines (Nature of Excitation Currents)

In the former post of singly-excited machines, some elementary machines were studied where their self inductances were functions of the rotor position and would change periodically with the rotor rotation. Now we study the conditions under which the currents ij and … Continue reading

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Singly-Excited Machines (Nature of Inductance Changes)

Some fundamental windings and core designs capable of producing a spatially periodic magnetic field were discussed Here. We are now interested in finding those configurations that while their self (or mutual) inductances depend on the rotor position, they change periodically as … Continue reading

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AC Heteropolar Windings

Before a discussion of drum windings that constitute the majority of the winding types used in the industry nowadays, we need to get familiar with varieties of windings from different points of views. In this discussion, only distributed three-phase windings … Continue reading

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Fundamental Requirements for Electromagnetic Energy Conversion

Necessary & Sufficient Conditions For Continuous & Unidirectional Electromagnetic Energy Conversion Consider that there are totally N parallel circuits in the stator and rotor slots of an elementary drum type electric machine. The windings are embedded inside the slots on the … Continue reading

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Geometric Structure of Electromechanical Devices

Facts Students of electrical engineering at the first days of their first electric machines course learn that rotating electric machines are classified into DC, induction and synchronous. They might get familiarized with switched reluctance (SR), stepping, PM brushless and axial-flux … Continue reading

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Three-Phase Fractional-Slot Windings

Background Fractional-slot windings were invented for some purpose that was totally different and limited from what they were later used for. Assume that the armature of a three-phase salient-pole synchronous generator is designed with nine slots per pole (like in … Continue reading

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