Induction Motor Slot Combinations Rules to Predetermine Crawling, Vibration, Noise and Hooks in the Speed-Torque Curve

Reduced-Order Model of Rotor Cage in Multiphase Induction Machines: Application on the Prediction of Torque Pulsations

“…As seen in Figure 2, each space harmonic "k" is projected on a cell represented by M kαs,rβ s,r (θ) (Equation (18)), which can be a two-by-two matrix, a two-element vector or a scalar, depending on the rules described below:…”

“…In fact, the induction machine is characterized by complex harmonic interactions due to the squirrel cage rotor structure, if this one is not well-designed dangerous phenomena could occur, especially torque ripple and mechanical vibrations. For the three-phase machines several design rules have been developed [2,18]. It must be mentioned that in the case of a three-phase machine, only one stator current harmonic is used to produce torque, which is not the case for a multiphase machine.…”

Calculation of the influence of slot geometry on the magnetic flux density of the air gap

“…However, this work will consider the empirical expression (3) proposed by Langsdorff for comparison of analytic results [10].…”

“…On double slotted air gaps, the Carter's factor is defined by the product of the rotor Carter's factor, cr k , and the stator Carter's factor, cs k . In this case, cr k and cs k are independently calculated using (1) and  is determined by equation (2) or (3) [1], [5], [6].…”

“…AGNETIC circuits of rotating machines are briefly composed by its ferromagnetic parts (rotor and stator) and air gap [1]. Thus, analytic equations and numerical method simulation are both used on magnetic circuit design process to determine parameters such as torque and machine excitation current [2], [3]. Magnetic flux distribution on air gap has great influence on machine performance because the most part of magnetic energy distribution is contained in air gap domain [1], [4].…”