Demonstrative Video
SECTION 01
Equation of Induced EMF
\[\begin{array}{cl}
Z= & \mbox{No. of conductors}=2T=2\times \mbox{No. of turns per
phase}\\
P= & \mbox{No. of poles}\\
f= & \mbox{frequency in Hz}\\
\Phi= & \mbox{flux/pole in webers}\\
K_{d}= & \mbox{distribution
factor}=\dfrac{\sin\left(m\beta/2\right)}{m\sin\left(\beta/2\right)}\\
K_{p}= & \mbox{pitch factor}=\cos\left(\alpha/2\right)\\
N= & \mbox{rotor rpm}
\end{array}\]
In one revolution of the rotor (i
In one revolution of the rotor (i.e. 60/N second) each stator conductor is cut by a flux of \(\Phi P\)
- Then,\[\begin{aligned} d\Phi & =\Phi P\\ dt & =60/N \end{aligned}\]
- Avg. emf induced per conductor\[\begin{aligned} & =\dfrac{d\Phi}{dt}\\ &=\dfrac{\Phi PN}{60}\\ & =\dfrac{\Phi P}{60}\times\dfrac{120f}{P}\\ & =2f\Phi \end{aligned}\]
- For Z-conductors in series/phase, Avg. emf/phase\[=2f\Phi Z=4f\Phi T\]
Equation is for full-pitched and concentrated coils
- R.M.S value of emf/phase\[=1.11\times4f\Phi T =4.44f\Phi T\]
Equation is for full-pitched and concentrated coils.
- Actually available voltage/phase\[= \boxed{4.44K_pK_df\Phi T}\]
Key Concepts
- \(K_p = \cos \left(5\alpha/2\right)\)\(5^{th}\)degrees (electrical) for the fundamental flux wave, then for different harmonics If the short-pitch angle or chording angle is\[\boxed{K_p = \cos \left(n\alpha/2\right)}\]
- Similarly, distribution factor for different harmonics\[\boxed{K_{d}=\dfrac{\sin \left(n \cdot m\beta/2\right)}{m\sin \left(n\beta/2\right)}}\]
- Frequency is also changed.\[\boxed{f_n=nf}\]