PM or solenoid?

[schwee]

I'm building a linear motor employing two coils, arranged axially, about 1" apart, with a hollow rod passing through the coils. I'm planning on embedding a soft iron slug or permanent magnet in the center of this hollow rod, and then energizing each coil alternately to pull the rod back and forth.

I'm finding it very hard to get soft iron or electrical steel rod (like AISI 1002 or 1005) in the quantity (2) and size (.5" and .75" dia, 1" long) that I want. However, it's easy to find permanent magnets in this size and quantity. Can I just substitute a permanent magnet? Will it work as well?

 

[Clyde38]

Read the attached. .

http://www-cdr.stanford.edu/dynamic/linear_engine/eng_ref/electric_motors/motion1.pdf

[link

http://www.linkedin.com/in/clydehancock

]

[/url]

 

[dgallup]

You can easily get 1008 which will work nearly as well as 1005, even more common is 12L14 which works just fine in many applications. 12L14 is cheap, readily available and very easy to machine. It is not a "magnetic grade" material but it is the low cost material of choice in thousands of magnetic applications.

 

[FeX32]

If you use a PM don't forget about the back emf you will induce on the coils.


Fe