Winding a strong electromagnet

[Xaverius]

@ CapnHook,
             
                any luck with electrical steel?  My next step is to try Magnetic Metals, magmet.com...............

[Honk]

Hi all.

Just a small question.

I believe your'e going to pulse this electromagnets of yours.
Have you considered the influence of inductance while designing it?
This is of utmost importance if you want a fast response time, aka fast RPM:s.
You might want to keep the inductance below 50mH or less, if possible.
There is a trade of: Higher efficiency = Higher inductance = Slow current build-up = Slow electromagnet.

If you measure the inductance and resistance you can use this calculator to see
how long it will take to reach a certain current level (the desired amp-turns).
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/indtra.html#c2
It has helped me out tremendously.

[Xaverius]

Hi all.

Just a small question.

I believe your'e going to pulse this electromagnets of yours.
Have you considered the influence of inductance while designing it?
This is of utmost importance if you want a fast response time, aka fast RPM:s.
You might want to keep the inductance below 50mH or less, if possible.
There is a trade of: Higher efficiency = Higher inductance = Slow current build-up = Slow electromagnet.

If you measure the inductance and resistance you can use this calculator to see
how long it will take to reach a certain current level (the desired amp-turns).
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/indtra.html#c2
It has helped me out tremendously.

Yes, the higher the Inductance, the higher the reactance, and the lower the current and reduced Ampere-turns. Laminated steel and/or parallel-wired multiple coils should eliminate this problem.

[Honk]

My own findings does not show any way to eliminate the sluggishness of high inductance at high RPM:s.
A high inductance will force you to increase pulse voltage just to apply the charge time you desire.
The increased voltage x current = a lot more power. This is not comparable to static mode.
It's possible it'll work for you depending on the wanted RPM. I wish you the best of luck in your research.

[capthook]

An application specific question on electromagnet core:

An Adams motor design:
1. The rotor magnet is attracted to the EM core
2. Just before dead center, the EM is powered on just enough to NEGATE the attraction
3. The rotor/magnet travels past the EM due to inertia

How will the permeability of the core effect operation?  Or will it be the same no matter?

(a) the higher the permeability, the greater/sooner the attraction so the better the propulsion
(b) the higher the permeability, the greater the % of domains aligned by the rotor magnet, thus the greater power required by the EM to NEGATE the attraction.

So:
(c) No matter the core, (a) is relative to (b), so any core will be the same net result?
or
(d) a higher permeability core means NEGATING the attraction is easier/lower power?

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(non-annealed, cold-rolled, so don't even know how much better it might be without heat treating)
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??