... obtain their real values. On the other hand,
Equations (9.35) – (9.36) lead to the equivalent circuit in Figure 9.12.
Once the layer currents I
1
, … I
n
are known, the total losses in the bar ...
9.4. SKIN EFFECT IN THE END RINGS VIA THE MULTILAYER
APPROACH
As the end rings are placed in air, although rather close to the motor
laminated stack, the skin effect in...
... and testing for induction
machines
• Integral induction motors: induction motors with the PWM converter
integrated into one piece
1.3. INDUCTION MACHINES IN APPLICATIONS
Induction motors ... closed)
windings of the rotor. The interaction between the stator produced field and the
rotor induced currents produces torque and thus operates the induction motor.
As...
... conductors on the part of the machine not
connected to the grid (the rotor, or the mover in general), - the secondary. If the
windings on the secondary (rotor) are closed, a.c. currents occur in the ... phase. In both cases the winding
arrangement on the part of the machine the primary–connected to the grid (the
stator in general) should produce a traveling f...
... this
combination.
The insulation of the coil conductors (turns) is applied before inserting the
coils in slots. The coils are vacuum also impregnated outside the machine. The
slot insulation ... ………
The connections between the coils of a phase and the leads to the terminal
box have to be insulated. Also the binding cord used to tie down endwindings to
r...
... and the other side in the second layer. They are
connected observing the inward (A, B, C) and outward (A’, B’, C’) directions of
currents in their sides.
Connecting the coils per phase
The ... Having two current paths, the current in the coils is half the current at the
terminals. Consequently, the wire gauge of conductors in the coils is smaller and
thus the c...
... calculated for the fundamental airgap flux density.
This information prepares the ground to define the parameters of the equivalent
circuit of the induction machine, that is, for the computation ... r
m4
, (for the stator)
and r
m2
(for the rotor). Assuming that the radial magnetic field H is constant
along the circles r
m2
and r
m4
, the flux linkage equivalenc...
...
The airgap flux does not reach the other slotted structure (Figure 6.10a)
while the zig-zag flux “snakes” out through the teeth around slot openings.
In general, they may be treated together ...
rotor phases. In reality the flux in the rotor varies at Sf
1
frequency, while in the
stator at f
1
frequency. The amplitude is the same and, with respect to each other,
th...
... addition to the emf, there is only the stator resistance and leakage
inductance voltage drop.
Finally, as there is current (mmf) in the rotor, the emf E
1
is produced
concurrently by the two ... constitute the IM equations per phase reduced to
the stator for the rotor circuit.
Notice that in these equations there is only one frequency, the stator
frequency ω
1
, whic...
... constant under steady state and the machine behaves like a
synchronous machine with the torque dependent on the power angle δ (S = f
2
/f
1
= ct).
On the other hand, the frequency f
2
may be varied ... when the load torque decreases, to reduce the flux level in the machine
and thus reduce the core losses and increase the power factor and efficiency
while stato...
... order is a
multiple of the number of slots (10.12). The stator (rotor) mmfs may produce
harmonics of the same order either as sourced in the mmf or from the interaction
with the first airgap magnetic ...
The saturation coefficient K
st
in (10.40) refers to the teeth zone only as the
harmonics wavelength is smaller than that of the fundamental and therefore the
fl...