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this process is repeated (i.e. current is removed from winding T at 270° and applied to winding S)
the shaft will continue to rotate. By continuation of the scheme, rotation is continued.
DC Control
The electrical windings will be energized near the peak of the waveform, to obtain maximum
torque from the motor. This corresponds to applying power over 60° as shown in Figure 3.. Since
there are six (6) different commutation sections, this commutation scheme is sometimes referred to
as a 6-step control.
This yields an "average" back-EMF of:
=
K
E
RMS
π
3
Where K
is measured phase to phase (φ−φ)
E
^
(COS 2π - COS π )
K
=
—3 K
E
E
RMS
2π
^
=
3 K
E
π
^
K
= 0.955 K
E
E
RMS
Figure 3. DC Control
Application Notes
2π
3
^
Sin φ
K
E
2π - π
3
3
3
3
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(6)
(7)
(8)
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Troubleshooting
