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Yaskawa Sigma Motors: 1/2 to 1/3 the physical
size and weight of non-sigma brushless motors.
- More torque
- Better efficiency
- 300% Rated torque for 3 seconds
- Higher
angular acceleration rates
- 2,000,000 hours MTBF
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How Yaskawa Engineered a Better Servo
Motor. |
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Older Style motors: Older style motors were wound with a needle, which required space
for the needle to travel and resulted in an inexact
winding. Only
40% of the slot was filled with copper.
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High Density Windings:
With Sigma Technology the motors have segmented
stators. Each
stator segment is wound separately and very precisely.
This results in a 70% space-fill factor. |
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Encapsulated Motor
Core: Because there is a higher density of wire, cooling
becomes critical. To increase heat dissipation in the
windings, the winding air gap is filled with a
heat-conductive resin. |
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Neodymium-iron-Boron (NdFeB) rotor
magnets:
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Reduction in the End
Turns: End turns are where the wire crosses over the
pole from one slot to another. Sigma Technology has shorter end turns leading to
smaller size and higher efficiency.
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Larger output shaft: Designed for machine tool industry these motors come
standard with a larger diameter output shaft.
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Improved
Roundness:
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Inside
the stator the bore is round to 0.001”
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The tighter specification is due partly to the fact
that the smaller motor segments are easier to machine,
and control quality on then a larger one piece stator.
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This specification allows for a smaller air gap. (which
reduces cogging)
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300% Rated torque for 3 seconds: The small size and
more efficient motor results in higher torques for longer periods of time. This higher
torque results in a faster acceleration rate: Thus the
more efficient trapezoidal motion profile can be used more
often.
Note:
Most manufactures can only maintain this higher torque
for a few milliseconds.
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Reliability and Quality: Based on field performance Sigma motors have an
incredible 2,000,000 hours MTBF. |
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Deming Application Award: Because of the outstanding achievements in quality
control, Yaskawa won the prestigious
Deming Application Award in 1984 after four years of
rigorous effort.
Today
Yaskawa remains the only company in the world, in its
field, to earn and maintain this award.
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