|
|
Nitinol Wire
"muscle wire"
Page 7
INDEX
NITINOL wire.
Opto-coupler, globe, motor,
INTRO
NITINOL WIRE
Nitinol wire is a very interesting output device or INDICATOR.
It is a wire that DECREASES in length when a current flows through it. This is
opposite to thermal expansion, where heating create an expansion. IN this case
heating creates a contraction about 100 times greater than normal expansion.
Current
through the wire produces heat and the amount of current must be carefully
controlled (limited) so that the wire does not get too hot. The wire is only
allowed to rise to a temperature to produce approx 6%
reduction in length.
There are a number of comments about this wire. It is very expensive
($xx per metre) and the speed of activation is about 1second for contraction plus approx
1second for the wire to cool and return to its original
length.
The other limiting factor is the need for a force to return it to its original
length. It does not return by itself.
The wire we use for the experiments is 0.004in (4 thousands of an inch) in
diameter. It produces a force (lifting power or pulling power) of xxxgm.
The force required to return it to its original length is xxxgm. If this
returning force is present all the time, the effective output force is 65gm -
25 = xxxgm.
If you have an application that meets these requirements, this project can be very impressive.
We have produced a 3-page technical article on NITINOL
wire with a list of suppliers, applications and complete technical details.
NEXT
|
|