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Fiber covered wire provides good mechanical properties,
chemical resistance and long term dielectric strength. Its insulation
value is derived to a large degree through greater separation of the conductors.
A fiber of textile serve is treated with a conductive substance and applied
as a braid, or more often as a spiral wrap. Fibers serves are used for
applications requiring extreme limpness, flexibility and long flex-life.
Many conductors utilize both film and fiber servings for a superior insulation
for specific applications. The recommended maximum operating temperatures
listed below are based on using these fiber insulations as secondary insulations
for film insulated litz wire.
| COTTON |
105°C |
Advantages
An inexpensive serving, cotton has good abrasion resistance.
Size range: 8-40 gauge. |
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Limitations
Poor space factor, non-solderable.
|
| SILK |
105°C |
Advantages
Silk has a good space factor as well as good abrasion resistance and
flexibility. It is slightly better than nylon for applications requiring
a minimum fiber wall.
Size range: 20-44 gauge. |
|
Limitations
Non-solerable, more expensive than other fibers.
|
| NYLON |
130°C |
Advantages
Nylon has a good space factor, excellent abrasion resistance, and
is solderable. It will not support combustion.
Size range: 3-44 gauge. |
|
Limitations
Not recommended where a minimum fiber wall is required.
|
| DACRON |
155°C |
Advantages
Dacron provides good abrasion resistance, solderability, and a slightly
higher maximum operating temperature than nylon.
Size range: 8-40 gauge. |
|
Limitations
Better space factor than cotton or fiberglass, but poorer than silk
or nylon.
|
| HIGH TEMPERATURE
NYLON (NOMEX™) |
250°C |
Advantages
This insulation has a good space factor and provides outstanding thermal
and chemical stability at high temperatures. It will not melt or support
combustion.
Size range: 8-40 gauge. |
|
Limitations
Non-solerable, more expensive than other fibers.
|
| FIBERGLASS |
260°C |
Advantages
Fiberglass provides good electrical properties at high temperatures.
Size Range: 8-40 gauge. |
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Limitations
Poor space factor, non-solderable.
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