301x Filetype PPTX File size 0.38 MB Source: uomustansiriyah.edu.iq
Reluctance Motor The origin of this motor can be traced back to 1842. The Synchronous reluctance motor has a stator wounded as that of a 3-phase induction machine. It works as a synchronous motor without DC field winding in its rotor. A reluctance motor is a type of electric motor that induces non-permanent magnetic poles on the ferromagnetic rotor. Torque is generated through the phenomenon of magnetic reluctance. Hence, it is not a permanent magnet motor, because its salient rotor is composed of soft ferromagnetic material (of a thin hysteresis loop with high remanence and small coercive force). Construction of Reluctance Motor Rotor 1- Notch-Type Rotor • “Notch” areas are of “High-Reluctance” • “Pole” areas are known as “Salient” Poles • Number of salient poles must match the number of stator poles Figure (2) 2- Flat and Barrier Slot Rotors Figure (4) Principle of Operation When a piece of magnetic material is free to move in a magnetic field, it will align itself with the magnetic field to minimize the reluctance of the magnetic circuit. To put it another way the piece will orient itself towards the magnetic pole creating the field. The torque on the rotor created in this way is called the reluctance torque. Figure (5) • Rotor accelerates towards synchronous speed • At a “critical” speed, the low- reluctance paths provided by the salient poles will cause them to “snap” into synchronism with the rotating flux. • When the rotor synchronizes, slip is equal to zero • Rotor pulled around by “reluctance torque” • Figure (6) shows the rotor Figure (6) synchronized at no load.
no reviews yet
Please Login to review.