Armature winding of synchronous machine either delivers 3 phase a.c source or its supplied by 3 phase a.c source and the field winding is energized from dc source. As in other rotating machine the emf induced in synchronous machine is motional emf so there must be relative motion between the conductors and magnetic field. Emf […]


Induction Motor Even if the machine is lossless we cannot ignore the electrical portion of airgap power which When we subtract friction and windage losses from the developed power then we obtain the shaft power. In Induction machine we do not merge core loss and mechanical loss as rotational loss because there location inside the […]


MMF Balancing In an Induction machine due to air gap between stator and rotor the magnetizing current drawn by the Stator is must be higher as compare to magnetizing current drawn by the transformer. hence  So usually we ignore   and only consider in the shunt branch. The magnetizing Reactance of a Induction motor is […]

ROTOR (Equivalent Circuit)

Under running condition the rotor frequency is scaled by a factor of “s” due to which all the parameters that are directly proportional to frequency such as emf and reactance also scaled by a factor of “s”. We considered the resistance to be independent of the frequency hence the rotor resistance remain same under standstill […]


In Induction machine both the stator and rotor winding carry current and produce flux due to which the resultant air gap flux is obtained by sum of the flux of the 2 winding and this resultant flux is responsible for inducing an e.m.f in stator as well as rotor winding. In an Induction machine rotor […]


When an Induction motor is supplied by 3 phase AC source on the rotor side and the stator terminals are short circuited through resistances the Induction motor is called as Inverted Induction motor or rotor fed Induction motor. This configuration is only possible for Slip ring Induction motor (SRIM) and not for Squirrel cage Induction […]


Induction Motor Speed of Stator magnetic field = Ns Speed of rotor = Nr Slip, S = (Ns-Nr) / Nr As the stator magnetic field rotates at Ns and the rotor rotates at Nr in the same direction the relative speed of magnetic field with respect to conductor is Ns-Nr In case of Induction motor […]

Rotor Construction Of an Induction Motor Squirrel Cage Rotor

Silicon steel is used for stator as well as rotor construction and in rotor as well as stator it is laminated to reduce eddy current losses. The stator frequency is generally higher then rotor frequency hence to reduce eddy current loss we make use of thinner lamination in stator and thicker lamination in rotor The […]


Application of Chopper Speed control of DC Motor. Positional control in robotics. Regulated power supply (SMPS). Input to Inverter. Solar Power Converter. Step Down Chopper CH: – fully controlled switch Operation: – Periodic Time period: – T Duty cycle: – Ton/T Ton = DT CH: – ON           Vo=Vs CH: – OFF          Io=0/Vo=0 Buck Converter S1 […]


The elements lie in d-block or f-block of periodic table and they have large number of unpaired electron which contribute to spin dipole moment so they have large dipole moment and are strongly magnetized. Example:- Fe, Co, Ni, Gd, Dy Since ferromagnetic material is a strongly magnetized the magnetic field line converge when they passed […]