Electromagnet Question

[mondrasek]

All,

I'm looking for an answer to this question:

If one is to energize any electromagnet (you pick the specs) for 1 msec, what is the power consumed by the electromagnet?

vs.

If one is to energize the same electomagnet for 1 msec, but this time, with a permanent magnet (you pick the specs) in close proximity such that the permanent magnet N pole is facing the electromagnet N pole so as to repel the permanent magnet, what is the power consumed by the electromagnet?

Sorry if this is known information.  I've not been able to find it and my experimental measurement capabilities are severely limited.

Thanks in advance!

M.

[Honk]

I totaly depends of the coil inductance, voltage applied and what amp turns you want to reach.
Amp turns is responsible for the magnetic flux strength. It's simply the number of turns times the applied current.
If your electromagnets is e'g 80mH 1000turns and 5 ohms then it will take you 1ms to reach 10 amps when 826V is applied.
Be aware of the peak power going into the coil at fast transients, in your case it comes to 10A * 826V = 8260 Watts.
If you just use 50V and let the resistance of the coil limit the current it will take you 0.2 sec (200ms) to reach 10 amps.
The peak power at 50V is just 500 watts but it occurs during a much longer time period and uses more average power.

This is where you calculate the respons time of a coil or an electromagnet for that matter.
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/indtra.html#c2

[Xaverius]

Hi Mondrasek, if you use an electromagnet rated at .01 Henry (10mh) with a coil resistance of 5 ohms and an applied Voltage of 10 volts, then at 1ms the power consumption would be 20 watts.

If the electromagnet is energized in proximity to a permanent magnet in repulsion the power consumption should be slightly more, maybe 21 of 22 watts.  When a magnetic force (the permanent magnet) is moved away from a coil of wire(in this case caused by repulsion) it generates electricity, so the power level rises, although only slightly.

[mondrasek]

Thanks guys.  Good info.

So, say one is to take a cylindrical electromagnet with opposite pole configuration.  Set it with the North pole facing up and uncharged.  Place a perminant magnet on top so that it's North pole is down and it is in contact with and in attraction to the ferous core of the electromagnet.  When you apply an electric source to the electromagnet it should repel the perminant magnet.

How much power is required to break the attraction of the perminant magnet to the electromagnet core?  How is the power of the electromagnet related to the strength/size of the perminant magnet? 

If two perminant magnets are forced together in a vertical arrangment so as to repel, and then the top magnet is released, it will accelerate upwards to a height much greater than where it will eventually settle and hover over the bottom magnet.  Can the electromagnet/perminant magnet arrangement be made to act the same?  What is the relationship of the power consumed by the electromagnet to the strength/size of the perminant magnet to create this equal opposing force?  Does the fact that we must first break the attraction require more power to the electromagnet than if there was not the attraction?  Does the acceleration of the perminant magnet away require more power to the electromagnet due to the fact that the perminant magnet is moving through the electromagnet field?  Or will the electromagnet field generate outwords from the center of it's core and drive the perminant magnet away so that the two fields never overlap?

Thanks again for your input.

M.

[mscoffman]

Thanks guys.  Good info.

So, say one is to take a cylindrical electromagnet with opposite pole configuration.  Set it with the North pole facing up and uncharged.  Place a perminant magnet on top so that it's North pole is down and it is in contact with and in attraction to the ferrous core of the electromagnet.  When you apply an electric source to the electromagnet it should repel the perminant magnet.

How much power is required to break the attraction of the perminant magnet to the electromagnet core?  How is the power of the electromagnet related to the strength/size of the perminant magnet? 

If two perminant magnets are forced together in a vertical arrangement so as to repel, and then the top magnet is released, it will accelerate upwards to a height much greater than where it will eventually settle and hover over the bottom magnet.  Can the electromagnet/perminant magnet arrangement be made to act the same?  What is the relationship of the power consumed by the electromagnet to the strength/size
of the perminant magnet to create this equal opposing force?  Does the fact that we must first break the attraction require more power to the electromagnet than if there was not the attraction?  Does the acceleration of the perminant magnet away require more power to the electromagnet due to the fact that the perminant magnet is moving through the electromagnet field?  Or will the electromagnet field generate outwords from the center of it's core and drive the perminant magnet away so that the two fields never overlap?

Thanks again for your input.

M.

These are good questions mondrasek. The electromagnet and the permanent magnet are interchangeable in their effects, you obviously
have to "fund" the solenoid with external energy. Field strength is measured in Gauss. A permanent magnet located near an electromagnet
will effect the current required due to higher inductance but only when the inductors field in changing, not when it is a constant. A moving
magnet in the field of inductor will induce a voltage that either adds to or subtracts from the voltage already on the inductor - that is
exactly the "generated" current. Whether the magnet is attracted to an off inductor depends on whether you use a ferrous core inside
the inductive coil to focus the magnetic flux. The magnet will be attracted to the core material but not to the inductor wire itself.
If you have a inductive coil of wire with no core switched off with no load resistance => no letnz law braking recirculation current will
occur in the wire.

If you want to know comparable Gauss between a permanent magnet and an electromagnet you need what is called a nonograph of the magnetic field strength as a function of diameter and length of the solenoid you can Google for them.  The strength is dependent on a lot of variables. A nonograph is like a multidimensional graph where  diameter, length, number of turns, gauge of wire resistance of the particular kind of wire, applied voltage ect.

A much better approach may be to do an experiment! With some regular insulated hookup you can wind a one layer solenoid
on a glass tube or a sawed off nail. Nails are not the greatest core material, Bedini SGS suggests welding rods. Put some
current through the solenoid in series a wire wound resistor or rheostat variable resister and see what it can do. Power equals
voltage times amperes. If you need some more Gauss power, then wind on some more wire turns. Make sure your solenoid doesn't
overheat. It's actually better to build your overunity machine out of solenoids first as they are completely adjustable, even though
they require DC current. Afterwords one can translate the fixed current solenoids to permanent magnets and things should operate
the same way.

I have an electronic circuit in mind that can run a Clanzer like overbalanced Wheel with solenoids wound around those eight
glass tubes. Once the wheel is turning it would be much easier to add external magnetics and watch the wheel's rpm to keep
it's power high as you go, while switching off each electronic sector as you add external magnets. If you add adjustable solenoids
first it seems almost certain one could achieve a working wheel, even though it might be very touchy dependent on field strength.
I think it makes more sense to tune a operating wheel then it does to try to make a non-operating wheel operate very close to unity.
I will post the circuit's flow diagram here once I have generate it. The hardest part is that one will need a slip-ring mechanism to get
dc current to the circuit board rotating with the center of the wheel.

:S:MarkSCoffman