Re: Electromagnet: Current or Voltage??


"Randy Gross" <aaawelder@xxxxxxxxx> wrote in message
news:xn0e6vr9x4lrac001@xxxxxxxxxxxxxxxxxxxxxxxxxx
> John Popelish wrote:
>
> > Randy Gross wrote:
> > > John Popelish wrote:
> > >
> > >
> > > > By power, I assume you mean flux.
> > >
> > > jpopelish@xxxxxxxx
> > >
> > > Yes. I'm looking to get maximum flux density. The electromagnet will
> > > only be used in a 12 vdc momentary burst so I need maximum
> > > capability in an instant for an instant.
> >
> > I'm not familiar with that measure of time, ;-)
>
> Sorry about the ambiguity.
>
> > Can you put any number on how long an instant is? I don't understand
> > if we are talking about a second or a nanosecond.
> >
> > > The width of the coil, including Iron core, is one inch. The length
> > > can be up to one inch. I have 18 awg. magnet wire to wind the coil.
> >
> > If you can explain more about what you need this flux for, I could
> > make better suggestions. After that it is a matter of writing and
> > solving an equation.
> jpopelish@xxxxxxxx
>
> This is an experiment in Torque.
>
> I'm building a motor from a different point of view. Instead of
> rotating the coil in a magnetic field, I'm mounting the magnets
> (1"x1/8" NEO disks) on the rotor and spinning the magnetic field.
>
> I want to use the coils, mounted in planetary fashion, like spark plugs
> in an engine with an adjustable "distributor" (armature) for energizing
> the coils mounted on the rotor. When the rotation of the magnets reach
> approximately 75 degrees to the coils, The coils (electromagnets) will
> energize wrenching the magnets toward 90 degrees but will de-energize
> before the poles try to cog on each other.
>
> At this time, I have no Idea what the RPMs will be so time for me is a
> best guess. I'm thinking low milli for about 13 degrees of rotation.
>
> The adj. feed is to time for maximum torque and to compensate for my
> shortcommings;-)
>
> rg

So, you are reinventing the permanent magnet DC motor??? In a traditional DC
motor, the communtator does the switching to direct the current to the
appropriate winding as it passed the magnets. What you have described sounds
similar to this. In a brushless DC motor, the switching is accomplished by
transistors or FETs turned on and off by hall effect or optical means as the
magnets or coils pass each other. It doesn't matter which moves, the coils
or the magnets. Motors have been built both ways, rotating coils and
rotating fields. The important thing is the magnetic path, it's reluctance
and the air gap. Get a book on motor design and study how they work, you'll
save your self a lot of frustration and avoid reinventing what was done 100
years ago.
Bob


.

Relevant Pages

  • Re: Electromagnet: Current or Voltage??
    ... you are reinventing the permanent magnet DC motor??? ... >> the current to the appropriate winding as it passed the magnets. ... the coils or the magnets. ...
    (sci.electronics.basics)
  • Re: Electromagnet: Current or Voltage??
    ... you are reinventing the permanent magnet DC motor??? ... >>> the current to the appropriate winding as it passed the magnets. ... >>> or coils pass each other. ... >>> coils and rotating fields. ...
    (sci.electronics.basics)
  • Re: Applying an accurate tension on a line being reeled in
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  • Re: rotating magnetic field
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