What is Litz Wire?
The term "Litz wire" is derived from the German word "litzendraht" meaning woven wire. It is contructed of individually insulated magnet wires either twisted or braided into a uniform pattern.
Litz wire sizes are often expressed in abbreviated format as follows:
N / XX, where N = the number of strands and XX = the AWG (American Wire Gauge) size of each strand. For example a typical size of litz wire might be expressed as:
"20/30" or 20 strands of 30 AWG. After the size follows the insulation and serving/jacketing options as will be described below.
Insulations:
Here we are describing the type of insulating enamel on each strand of magnet wire. The most common insulations for litz are *Single* & *Heavy* build Polyurethane-Nylon meeting the NEMA MW 80-C industry standard for magnet wire. Other insulations types & builds are possible so please inquire. You can find additional information on the various enamels available on our web site under:"
Twisting Tightness:
The standard twist configuration is 12 twists per foot (TPF) on most litz wires however non-std twisting is available on request. Sometimes the twisting is expressed as twist per inch (TPI). The maximum # of twists in a given length is limited by the size of the strands. Generally speaking, even in the smallest wire diameters, the highest TPF possible is 300 - 360 TPF.
Served vs Unserved:
Litz wire may be quoted as "SERVED" &
"UNSERVED". SERVED simply means that the
entire litz construction is wrapped with a
nylon textile or yarn for added strength and
protection. Another option is to have the
litz construction jacketed with FEP *TEFLON
(tm) or PVC instead of the nylon serving.
Typical teflon thickness is .005" wall up
to .015".
*TEFLON is a tradename of Dupont Corp.
Why Use Litz Wire?
Litz construction is designed to minimize
the power losses exhibited in solid
conductors due to "skin effect".
Skin Effect is the tendency of radio
frequency current to be concentrated
at the surface of the conductor.
Litz constructions counteract this effect
by increasing the amount of surface area
without significantly increasing
the size of the conductor. Generally
speaking, constructions composed of many
strands of finer wires are best for the
higher frequency applications.
Polyurethane-Nylon is the film most often
used for insulating individual strands
because of its solderability. However, you
may feel free to inquire about other higher
temperature insulations as well.
Frequency vs. AWG Strand Size
All Values in KHz
1 To 10.0 - 30 AWG
10 To 50.0 - 33 AWG
50 To 100.0 - 36 AWG
100 To 200.0 - 38 AWG
200 To 400.0 - 40 AWG
400 To 800.0 - 42 AWG
800 To 1600 - 44 AWG
1600 To 3200 - 46 AWG
3200 To 5000 - 48 AWG
