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 Cost
Reduction
Thermoplastic encapsulation enables cost reduction
vs. alternative methods of construction. Manufacturing cycle times and work-in-process
are dramatically reduced, and significant numbers of components are typically
eliminated. As an example, Encap often incorporates mounting and termination
features directly into the encapsulated design. High capital cost operations
such as trickle varnish are eliminated, as well as steps such as taping,
tying, machining, and curing.
Thermal Dissipation
Encapsulation with standard thermoplastics typically leads to hot spot temperature
reductions relative to open systems, due to the inherent thermal transfer
advantages of conduction relative to convection. Use of a thermally conductive
plastic can provide even greater thermal benefits. Key to this behavior
is the intimate contact with wound components enabled by encapsulation.
For reference, air has a thermal conductivity of approximately 0.01 W/m
K, and standard thermoplastics are 0.1 to 0.35 W/m K. Thermally conductive
polymers can be tailored to values from 0.5 W/m K to 50 W/m K.
Reductions in thermal rise translate to:
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Increases in torque and power |
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Movement to lower UL thermal classes |
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Ability to downsize components |
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Faster electrical response times |
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Longer life components |
Vibration Damping
Thermoplastic encapsulation of components enables
the design of a system with improved acoustic and vibratory characteristics.
When encapsulating, a new structure is produced with characteristics very
different from the previously separate components. The resonant frequencies
of this
unified structure can then be controlled and shifted using a proprietary
process control technology and by the tailoring of the encapsulant stiffness
and loss factor properties.
Encap has designed components such that encapsulation
enabled peak vibration reduction exceeding 5 decibels. Encapsulant properties
are modified for the specific system requirements, with polymers developed
ranging from ultra stiff composites to flexible thermoplastic elastomers.
CTE / Tighter Tolerance
Thermoplastic encapsulation facilitates the
construction of electromagnetic devices with greatly improved tolerances.
By eliminating multiple components, stack up tolerances are drastically
reduced. For example, Encap has used this approach in locating motor bearings
directly off encapsulated stators, thus eliminating end brackets and associated
components. Reduced air gaps are also made possible.
Thermoplastics have been developed with coefficient
of thermal expansion (CTE) approaching that of steel. Other materials were
developed to match the CTE of copper inserts, allowing for significant advantages
in hermetic sealing of encapsulated components. Low CTE combined with process
technology enables molding of parts with extremely tight tolerances, in
some cases superior to that of machined metal components.
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