0.3mm Color (Green, Red, Purple) Enameled Wire for Decoration
| Enameled Type | Polyester | Modified Polyester | polyester-imide | Polyamide-imide | polyester-imide /Polyamide-imide |
| Insulation Type | PEW/130 | PEW(G)/155 | EIW/180 | EI/AIW/200 | EIW(EI/AIW)220 |
| Thermal class | 130, CLASS B | 155, CLASS F | 180, CLASS H | 200, CLASS C | 220, CLASS N |
| Standard | IEC60317-0-2 IEC60317-29 MW36-A | IEC60317-0-2 IEC60317-29MW36-A | IEC60317-0-2 IEC60317-29 MW36-A | IEC60317-0-2 IEC60317-29 MW36-A | IEC60317-0-2 IEC60317-29 MW36-A |
Magnet wire or enameled wire is a copper or aluminum wire coated
with a very thin layer of insulation. It is used in the
construction of transformers, inductors, motors, generators,
speakers, hard disk head actuators, electromagnets, electric guitar
pickups and other applications that require tight coils of
insulated wire.
The wire itself is most often fully annealed, electrolytically
refined copper. Aluminum magnet wire is sometimes used for large
transformers and motors. The insulation is typically made of tough
polymer film materials rather than enamel, as the name might
suggest.
Type
Like other wire, magnet wire is classified by diameter (AWG number,
SWG or millimeters) or area (square millimeters), temperature
class, and insulation class.
Cross-sectional view of AWG33 magnet wire taken using a scanning
electron microscope
Breakdown voltage depends on the thickness of the covering, which
can be of 3 types: Grade 1, Grade 2 and Grade 3. Higher grades have
thicker insulation and thus higher breakdown voltages.
The temperature class indicates the temperature of the wire at
which it has a 20,000 hour service life. At lower temperatures the
service life of the wire is longer (about a factor of 2 for every
10 °C lower temperature). Common temperature classes are 105 °C,
130 °C, 155 °C, 180 °C and 220 °C.
Insulation
Although described as "enameled", enameled wire is not, in fact,
coated with a layer of enamel paint or vitreous enamel made of
fused glass powder. Modern magnet wire typically uses one to four
layers (in the case of quad-film type wire) of polymer film
insulation, often of two different compositions, to provide a
tough, continuous insulating layer. Magnet wire insulating films
use (in order of increasing temperature range) polyvinyl formal
(Formvar), polyurethane, polyamide, polyester, polyester-polyimide,
polyamide-polyimide (or amide-imide), and polyimide. Polyimide
insulated magnet wire is capable of operation at up to 250 °C. The
insulation of thicker square or rectangular magnet wire is often
augmented by wrapping it with a high-temperature polyimide or
fiberglass tape, and completed windings are often vacuum
impregnated with an insulating varnish to improve insulation
strength and long-term reliability of the winding.
Self-supporting coils are wound with wire coated with at least two
layers, the outermost being a thermoplastic that bonds the turns
together when heated.
Other types of insulation such as fiberglass yarn with varnish,
aramid paper, kraft paper, mica, and polyester film are also widely
used across the world for various applications like transformers
and reactors. In the audio sector, a wire of silver construction,
and various other insulators, such as cotton (sometimes permeated
with some kind of coagulating agent/thickener, such as beeswax) and
polytetrafluoroethylene (Teflon) can be found. Older insulation
materials included cotton, paper, or silk, but these are only
useful for low-temperature applications (up to 105°C).
For ease of manufacturing, some low-temperature-grade magnet wire
has insulation that can be removed by the heat of soldering. This
means that electrical connections at the ends can be made without
stripping off the insulation first.
