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02/02/23 11:00:18

@lecture @IS @py7002

Windings of each stator affect the others (in terms of inducing voltage) not just the rotor.
If angular velocity of rotor and stator are the same, there is no change in flux, no torque.
In a single loop, you have a pulsating torque, can be smoothed by adding more loops (squirrel cage).
Slip speed is the speed of the magnetic field relative to the rotor.
ag stands for ‘air gap’.

By inducing current back into the stator.
At what frequency does the rotor induce current back into the stator?
- In the frame of the rotor, if magnetic field is ahead of you at 2Hz so 2 revolutions per second. If the rotor is rotating at 48 revolutions per sec, then in a non relative frame the induced current is 50Hz.
- Makes sense, in the stationary frame.
Equivalent circuit, for each winding.
Mutual interaction between windings, given by $L_{m}$ .
$R_{r}$ resistance of the rotor (aggregate).
Angle between $V_{s}$ and $I_{s}$ current in inductor is shifted $π /2$ from the voltage.
$P_{a g}$ power transferred from stator into rotor.
$R_{r}$ is losses in power in windings and the transfer of mechanical energy into the rotor.
The pedagogy is all over the place, like we’re doing this after just learning phasors with Dmcc.
$I_{r}$ is the current induced in the stator, by the rotating rotor.
$V_{s}$ is voltage drop induced in stator and $E_{a g}$
- Kirchoffs law apparentely. Work around first loop
Influence of rotor on stator is the main factor, under normal conditions (the right hand circuit in the equivalent circuit).
Vast majority of motors operate with frequency adjuster (as this can affect rotations of rotor).
Pushing frequency of mains, current induced goes down.
I hate when lecturers ask questions while not asking them.
Quick detour into how the steam engine powered the British empire in the 19th century.