iron cores, for my electromagnet motor ? (question).

[nitinnun]

i want to build my own home made induction motor.
using electromagnets only.


which of the following iron cores,
would be the strongest ?


1:
thick steel pipe.


2:
dozzens of "strands",
of steel wire,
bundled together into a "bar".

that looks like this, from the top:

      oooooo
     ooooooo
      oooooo


3:
a dozzen turns of steel wire,
wrapped into a "donut".
shaped like a donut that homer simpson might mindlessly consume.

with the wire coil,
wrapped around the outside,
of the steel donut.


4:
a dozzen turns of steel coil,
shaped like a solenoid wire coil.
with the magnet wire wrapped around its outside.

that looks like this, from the side:

        ====
        ====
        ====
        ====
        ====
        ====


5:
thin steel sheeting,
which is wrapped into a tube.


6:
thin steel sheeting,
which is wrapped into a "bar".


7:
thin steel sheeting,
cut into sheets.

the sheets stacked into a cube.
(and wrapped tightly together, by tape).

[SomedayIsle]

I'd go with the steel pipe for it's obvious multipurpose use.....


In case the infernal machine refuses your demands.

[z.monkey]

In case the infernal machine refuses your demands.

Confounded Technology!

Most motors use laminated sheets of soft iron for the magnet cores.

The sheets an be cut and stacked to accommodate the radius of the armature.

Tight clearances between the electromagnets and the armature is important...

Been there, done that...

[X00013]

http://search.nasa.gov/search/search.jsp?nasaInclude=magnet+motor&entqr=0&output=xml_no_dtd&sort=date%3AD%3AL%3Ad1&ud=1&site=nasa_collection&client=nasa_production&ie=UTF-8&oe=UTF-8&simple_start=&news_start=&images_start=&videos_start=&podcasts_start=&baynote_start=&baynoteOrGSA=baynote

[nitinnun]

i came up with a solution.


i will wrap magnet wire, around a flat piece of cardboard.
then wrap thin steel sheeting, around the magnet wire.

my reasoning is that i only need steel, where i need the magnetic field.
and i only need the magnetic field, close to the rotor.



i looked at a box fan motor.
the box fan motor had a steel core, holding the magnet wire.

but otherwise, little of the steel was contacting the rotor.
most of the magnet wire, wasn't even close to the rotor !



i suspect that ALL of the magnet wires magnetic field,
goes into the small amount of steel, which is contacting the rotor.

compared to having steel all around the coil.
and having the magnetic field wasted that way.