CLASSIFICATION OF ELECTRICAL MACHINE
(a) motor
       1) DC motor
       2) AC motor
                    * synchronous motor
                    * induction motor
                                       # squirrel cage rotor   (the most common AC motor)
                                       # wound rotor           (for variable speed)
(b) generator

INDUCTION MOTOR
the synchronous speed of 50Hz induction motor :
poles per phase 2 4 6 8 10 12
rpm 3000 1500 1000 750 600 500

the synchronous speed (Ns) in rpm is given by :
                                       Ns = 120 f / p
                                       where f = frequency & p = poles per phase

BACK EMF
it is also called counter electromotive force ( cemf )
under construction !!

SOFT STARTING
Y :      higher V & lower I
Δ :      lower V & higher I
thus, always star then delta , just remember Star Buck @ Star Duck @ Why Duck ?
under construction !!

CLASSIFICATION OF NEMA MOTOR
under construction !!

INGRESS PROCTECTION
under construction !!

EXPLOSION PROOF
under construction !!

AC TO DC
under construction !!

DC TO AC
under construction !!

EARTHING
under construction !!

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