class: center, middle # EE-362 ELECTROMECHANICAL ENERGY CONVERSION-II ## Ozan Keysan [ozan.keysan.me](http://ozan.keysan.me) Office: C-113
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Tel: 210 7586 --- # Review: -- - ## Distribution Factor (\\(k_d\\)) - ## Pitch Factor or chording factor (\\(k_p\\)) --- # Distribution Factor ## \\(k_d = \dfrac{sin(q \dfrac{\alpha}{2})}{q sin(\dfrac{\alpha}{2})}\\) ## \\(q\\): Number of coils ## \\(\alpha\\): Angle between each coil --- #Pitch Factor (or Chording Factor) ## Voltage in a short-pitched coil is less than a full-pitched coil # \\(k_p = sin(\dfrac{\lambda}{2})\\) # \\(\lambda\\): Coil-pitch in electrical degrees --- # Pitch and Distribution Factor for Harmonics ## For harmonic number n: ## \\(k_p(n) = sin(\dfrac{n\lambda}{2})\\) ## \\(k_d(n) = \dfrac{sin(q n \dfrac{\alpha}{2})}{q sin(\dfrac{n\alpha}{2})}\\) --- # Winding Factor: ## is the combination of distribution and pitch factor #\\(k_w = k_d \times k_p\\) ## gives an idea about the magnitude of the coil voltage (or MMF) compared to concentrated and full-pitched winding. --- # Example: ## Assume a 2-pole 3-phase stator winding in a 12 slots machine. -- ## Plot the developed winding diagram assuming a 5/6 pitched coil. -- ## Not possible to achive in single layer: ## Solution: Use double-layer winding --- # Example cont.: ## a) Calculate the span angle of the stator coils, and the corresponding pitch factor. -- ## b) Calculate the distribution factor. -- ## c) Repeat the same for the 3rd and 5th harmonics --- # Example -- ## 3-phase, 4-pole AC machine has the following winding distribution: -- - ## double-layer, full-pitched in 24 slots -- - ## Number of series turns per phase is 80. -- ## a)Plot the winding diagram in a developed graph. --- ## Assume the rotor is a 4-pole permanent-magnet rotor that produces sinusoidal air-gap flux density and the flux produced per-pole is 0.03 Wb -- - ## b) Calculate the RMS value and the frequency phase voltage(open-circuited) of stator winding, when the rotor is rotating at 1500 rpm CW. --- ## c) Now a cylindrical rotor with 12 slots replaces the PM rotor. ## Plot the winding diagram for single layer, full-pitched 3-phase rotor. --- ## d) Now, the rotor is supplied from a source with unknown frequency. ## In order to generate 50 Hz voltage in the stator, what should be the frequency of rotor currents: -- - ## i) when the rotor is stationary -- ## ii) when it is driven in the CW direction at 1500 rpm. --- ## You can download this presentation from: [keysan.me/ee362](http://keysan.me/ee362)