do have color-coded wiring. The color-coded wire in
NAVEDTRA 10563. For more detailed information on
hand-wrapped assemblies offers an advantage because
wire-wrap tools and techniques, refer to MILSTD
each wire is distinctive and fewer errors are likely to
1130B, Notice 2, of 20 July 1983, C o n n e c t i o n s ,
result.
Electrical, Solderless, Wrapped.
TECHNIQUES
PRINCIPLES
The techniques of wire wrapping are simple. Simply
The principles behind wire wraps are simple. For
s t a t e d , the process involves coiling a special
proper conduction to occur between two metals, the
solid-conductor insulated wire tightly around a pin.
oxide coating that has formed on both surfaces must first
Although the process is simple, you must use skill and
be penetrated. Remember, the pins used in wire wraps
judgment to perform the steps correctly. Refer to figure
are squared off. They have cornered edges that will
5-17 as you read the following paragraphs.
penetrate the oxide coating of the wire when it is
properly wound on the pin. The edges will also lose their
Using Correct Procedures
oxide coating when they penetrate the surface of the
wire. The junction formed is strong, gastight (tight
Your first step in wire wrapping is to determine the
enough to seal out gases, in addition to liquids), and
correct gauge of wire you need to perform the job. Strip
resistive to corrosion.
MATERIALS
For wire wrapping, a special solid-conductor
insulated wire is required. This type of wire allows the
coil to form tightly about the pin and remain that way
without noticeable slippage. The wire is a composition
of a silver alloy with a copper coating. Silver offers an
advantage in that its oxide is almost as conductive as the
metal itself. The insulation material used on the wire is
usually Teflon or Meline. Teflon offers the advantage of
very high temperature stability and ease of cutting (for
stripping by automatic machinery). Teflon, however,
also has the undesirable trait of "cold flow." Cold flow
results when the insulation gradually reduces or wears
away at a point of pressure. When Teflon-insulated wire
is in contact with a pin and cold flow occurs, an
intermittent short may occur at that point. Meline
withstands continued exposure to pressure much better
than Teflon. Although Meline is more resistive to cold
flow, it does not have the high-temperature stability of
Teflon. Because of the cold flow problem, however,
Meline has become more widely used.
TOOLS
Some ships will have wire-wrap kits for you to use.
Other ships may require you to use certain hand tools
a u t h o r i z e d for wire-wrapping procedures. Several
useful tools, as well as the techniques for using them,
have been developed for doing wire wraps. The tools
shown in figures 5-17 through 5-19 provide limited
examples. For a basic source of wire-wrap tools, refer
to Gas Turbine Systems Technician (Electrical) 3/Gas
Figure 5-17.--Basic wire-wrap procedure.
Turbine Systems Technician (Mechcmical) 3, Volume 1,
5-15
