Recent content by EddieP

Thanks Lnewqban, I appreciate your answer. The vacuum would be ideal, but it is an extra step I am trying to avoid if I can. With regards to the oxidation, I should have said the material in question is actually a graphite powder. Sorry, I overlooked mentioning that. It seems that graphite...

A cylinder contains a powder made up two substances - spherical grains of metal and spherical grains of plastic. In between the grains are voids, so that the cylinder is made up of 75% powder grains and 25% air. The cylinder is oriented vertically. It is sealed at the bottom and open at the top...

I am interested in the potential for air bubbles in a plastic structure to expand with heat, and put pressure on the plastic surrounding the air bubble. In this case the plastic structure is formed by melting a thermoplastic powder. In between the grains of powder are voids with air in them. As...

Please excuse me if this is a very basic question, but I am just hoping someone can enlighten me on something. I am using the program FEMM to simulate a transformer. Unfortunately, I am unable to find data on the BH Curve of the material I’m using for the core, and I am worried that my...

Hello Hesch, Thanks very much for your answer - it was a great help. I used the formula EMFrms = 4.44 * f * N * A * B to compare two transformers, one that was 80% the size of the other - 80% of the core cross section, and 80% the number of turns in the coil (same wire cross section, same...

Hello, I am wondering if anyone can help me with the following question. I want to find out how the size of the core in an inductor influences the current induced in the secondary coil, and whether a smaller core is more efficient if efficiency is defined as inducing the highest current in the...

I am trying estimate the approximate value in gauss of the magnetic field of a magnet I have based on its pull force, and I am wondering if anyone can comment on the validity of my method. I have tested the pull force of my magnet by weighing the heaviest object it can hold. I have also found...

I was wondering if I could ask a question on the magnetic field surrounding a current-carrying wire, and how this field might change with the presence of other, ferrous materials nearby. I have been using this web page http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magcur.html#c3 to...

I am interested in calculating the magnetic field around a wire. Using the formula found here http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magcur.html#c3 I can calculate that B = (μ0*I)/(2*pi*r) Where I equal current in Amperes, and r equals distance from the wire in meters. This gives...

Suppose I have a plastic tube about 70% full with magnetic powder, with a copper coil solenoid around the cylinder. By "magnetic powder" I mean each particle is actually a tiny permanent magnet with its own magnetic field. - like you can see in this video When there is no externally applied...

I have a question about magnetic repulsion. Suppose I have a permanent magnet (axially magnetized) placed on top of the iron core of an electromagnet. I want to switch on the elctromagnet to repel the permanent magnet. (Please assume the permanent magnet is contained in some kind of tube that...

I am trying to calculate the magnetic field (in tesla/gauss) of an iron core electromagnet that is very small and has very few windings. For example 12 windings over 0.003 meters. I know this is not going to produce a very strong field, but I would like to pulse a strong current through the coil...

I am interested in calculating the magnetic field strength produced by an electromagnet with a core shaped like an O that forms a closed magnetic circuit, shown in the attached image that can also be seen here -...

I am 36. Never really studied much Science and zero Physics. I am trying to educate myself, and I am also interested in designing electromagnets and other things. I will try my very best not to post ignorant questions. I always research thoroughly before posting . Thanks everyone