3380Views24Replies

# Earth Magnets vs Electromagnets?? Answered

I have an earth magnet/ neodymium magnet that is pretty strong as far as pulling power is concerned but would an electro magnet have more pulling force or power. Its a small enough earth magnet that fits in my pocket. Thanks. AL.

Tags:

## 25 Replies

How about combing the two. ( corrected an error )

Add a nib magnet to an electromagnet and suddenly you have more flux
a stronger force for less expended I2*R heating of electric power.

How to reduce the flux ?............ Just reverse the DC current flow..... A

alsports2000 (author)2011-07-24

ICENG, thats a very interesting concept but just how do you reverse the DC current? Also, what is a nib magnet?. Thanks.

iceng (author)2011-07-25
There are 5 steps and a you-understood  variable power supply.
There is NIB neodymium magnet with a strength of 12 MT magnet turns.
The color RED is magnetic South, color BLUE is magnetic North and WHITE
represents no magnetic polarity.
Each step shows a meter reading of the current that is flowing through the
six wire turns on the plastic coil bobbin.
The bobbin fits over a soft magnetic iron rod held in position with iron ends.
1. Step 1  nothing is happening.  Current is 0.0 Amp, no magnetic flux.
2. This Step we set the variable power supply to deliver6.0 amperes into the six coil wire turns.generating 6 x 6 = 36 MT of flux. Note the BLUE North and the RED South Electromagnet color designation.. Also note the 6.0 Amp meter reading and the current direction arrows Also note the flux lines representing the orientation of part of the magnetic field.  Finally observe the cut away round window is simply showing a soft iron rod in the center of the bobbin...
3. In this Step we do the extraordinary act of cutting out a segment of the iron rod and replacing it with the NIB magnet.  The magnet 12 MT gets added to the electromagnet 36  MT for a higher total of 48 MT magnet turns of  magneto-motive flux.  This increased flux is achieved at no additional current and therefore no additional I2R heating losses in the coil.  More flux with less energy and less heat...WONDERFUL. Finally observe the cut away round window is showing a NIB magnet  residing in between the soft iron rod in the center of the bobbin..
4. Now, what happens if we set the variable power supply to zero amperes at the coil ?  Well the magnet still delivers a magnet motive force of 12 MT not the zero OFF position we wanted.
5. In this final Step we reverse the direction of the variable power supply and increase the current to -2.0 Amp x 6 Turns = -12 MT negating the positive magnet of 12 MT resulting in a net total 0.0 MT flux.  The novel feature here is that we reduce the magneto-motive flux of the system
to zero for the very low two amperes a very low heating value.
In conclusion electromagnets can be made smaller with the same clamping
ability for less over all heating energy through the appropriate application of
NIB magnets in their Constitution.

A

alsports2000 (author)2011-07-25

That was Awesome Iceng, you are a master of magnetics. Thank you so much for the information and will take me a while to digest all of it but I will eventually duplicate your experiment. Thanks again. AL.

iceng (author)2011-07-26

This site might interest you.
The green is a magnetic window worth having........   A

PiyushJ5 (author)2015-09-30

iceng (author)2015-09-30

iceng

PiyushJ5 (author)2015-09-30

steveastrouk (author)2011-07-17

I don't see how this question is different from your last one. An electromagnet could be stronger, in the same space.

Steve

alsports2000 (author)2011-07-17

Thank you for taking the time to respond and I think what I am looking for is a comparison of pulling force or power from both and I don't know that an electro magnet is capable of this. Thanks. AL.

steveastrouk (author)2011-07-17

Like I said before, yes, an electromagnet can be very much stronger - but where will the power come from ?

newmyCF (author)2015-05-12

if you're comparing based on volume then in at least some of your calculations depending on the application, you'll be more realistic to add the volume occupied by the power source of the inductor, and if you add in time dynamics you see that it's impossible to match for certain scenarios. With servo-dynamics you can also make up for the inability of a fixed modify the force exerted to a given point. Also - you responded a few years ago -- pretty awesome how much stronger these things are getting right?? But you're obviously absolutely right about being able to match the field of a fixed magnet with that of an equivalently sized inductor if you ignore the size/volume of the power source, at least in most practical cases I can think of

64bitgenius (author)2011-07-16

it depends on the electro magnet, and on the neodymium magnet.

alsports2000 (author)2011-07-16

Thank you for taking the time to respond but the earth magnet I am referring to I can carry in my pocket: its a 1/2 by 1/4 by 2 inches long. I sandwiched it with two  pieces of metal so it could improve on the pulling power. I've seen videos of electro magnets here and what they all seem to do is pick up a paper clip. What exactly are electro magnets suppose to do??. THANKS. AL.

64bitgenius (author)2011-07-21

electromagnets vary in strength, and to put it simple, the more coils on it, the more magnetism, but the more resistance, and the more current, the higher the strength. I've built an electro magnet powerful enough to pull a good 6 steel razor blades. I made it with a 1/2 inch bar of iron, 150 coils with 20 gauge wire, and 12 volts dc at 1.5 amps for power. electro magnets are basically regular magnets, 'cept that when power is removed, the electro magnet does not have any pulling power. also, electro magnets are not always weak enough to only pull a paper clip; there was one electro magnet I forgot where and when, and the name, but it could levitate a frog O.o electro magnets are used everywhere, like in dc moters in an rc car, or rc boat/plane, or in a fan.

alsports2000 (author)2011-07-22

Thank you very much 64bitgenius for sharing your knowledge of electromagnets and I never doubted your intelligence of the subject but I would like to know how you handled the overheating aspect of your electromagnet??. Thanks. AL.

64bitgenius (author)2011-07-24

actually, the iron bar seemed to have dispersed a lot of the heat, and combined with the resistance of the wire, it didn't overheat, so i honestly don't know how I would handle overheating. You can prevent too much heat by either turning down the current, or add a resistor, though, but using those solutions would bring down the overall magnetism.

alsports2000 (author)2011-07-24

Thank you 64bitgenius for enlightening us/me with your response. I think my overheating problem is due to the size of the screw. Its a small 1 1/2 long and pretty narrow and a D battery is too much current for that small screw. I am going to duplicate what you did and see if it can hold off the overheating problem. ALL of you guys answers are the best answers anyone could ask for. Thanks again. AL.

seandogue (author)2011-07-17

lol, take a look at a refuse yard. They're used to pick up VERY heavy items. Rare earth have an advantage when it comes to size, but they cannot be turned on and off and are quite brittle, making them unsuitable for use in many applications. Electromagnets have a purpose but it's not always the same as that of a rare-earth magnets.

alsports2000 (author)2011-07-17

THANK YOU FOR RESPONDING. AL.

kelseymh (author)2011-07-17

What was wrong with the answers to your previous questions? Or are you just trolling?

You would need a pretty powerful electromagnet to equal that neodymium magnet you have.

alsports2000 (author)2011-07-17

Thank you for responding and I would have to agree with you on the advantages of an earth magnet. It never needs cooling either. Thanks. AL.

iceng (author)2011-07-16

Don't give up on military force generation
Very polite AL you are
More flux when answer value is unforced

lemonie (author)2011-07-16

No, stick with what you have.

L