Everything posted by eointremont
Danijel, Thanks for the tip; I was actually intending to only use passive cooling which means I'll take your advice and add more turns to the core. Question, is it recommended to wind over the first layer of coils (the coils I have are enameled, so electricity shouldn't travel through the second layer of winding)? Would the net magnetic field just be amplified? Have you also worked with an e shaped iron core? I extracted mine from a microwave transformer and removed the base. Winding around the middle section is a little tricky, especially if I want to get a tight and compact wound. This is due to the geometry of the core being rectangular rather than circular. Just wondering if you have any suggestions on winding on an awkward shape like this and also if there are any "adhesives" (for a lack of better word) for the coils so that they don't come undone. Picture is attached for a better visual (note that this winding is not the finished product, I'm still trying to figure out how to keep the wounds tight and compact like you stated). Thanks!
Thanks for your answer. I'll check out Femm as I know it'll be helpful in the near future. Actually, I can fit about 80 turns of wire, but I chose 1" or 2.54cm as the height of the core. I could always use more turns, but I was wary about overheated the wire as you mentioned. I got 74A of current by using Ohm's law - 30V divided by 0.405ohms. Not sure if I had done that correctly, but I guess it wouldn't really matter since the max the power supply would give is 10A anyways. I'm simply using liquid nitrogen for cooling the superconductor. So far I've only tested it on permanent magnets and it works, but I want to experiment with an electromagnet that I can control the magnetic field strength (basically the current). This also had me thinking about the risk of electricity conducting through the condensing water vapor caused by the cooled superconductor. Basically, the concept should be the same; if the superconductor levitates with a permanent magnet, it could surely work with an electromagnet (DC current). It's just I'd like to make sure things are safe and effective before investing in buying more materials (such as the power supply, which I haven't bought yet). Are you familiar with overheating of wires? Any tips on cooling? Thanks! I'll check this experiment out. Very helpful!
Hello all! I'm designing an experiment of using a variable voltage power supply (0-30V, max 10A) to power magnetic copper wires wrapped around an E shaped iron core. The wire has a resistance of 0.000533 ohms per cm, the diameter of the wire is 0.065cm, the iron core's dimensions are 2.54x3x6.5 cm3. From the calculations, I found that it takes roughly 40 'turns' of the wire around the core; this is in total 760cm of wire length (minus the wire length between the core and the power supply). The total resistance I found in the coil would be 0.405 ohms. From Ohm's Law, I would get around 74A of current from this setup. Questions: 1. To calculate the magnetic field of a point above the iron core, would I use B=mu*(N/L)*I? Or is this only for the center of a solenoid? 2. The max current running through the wire is 10A. Based on the setup, I'm wondering if this is sufficient to produce a "strong" magnetic field. To find out this strength, would I need to find out the magnetic field, and then its corresponding force at a certain point? 3. The experiment is for maglev purposes actually; I have a superconductor that I'd like to try to see how variable voltage can change the distance between it and the iron core. With this in mind, would my calculations also require a force diagram of the weight of the superconductor and the magnetic force and then I'd be able to find the distance between them at a certain voltage? 4. Finally, I am very new to electricity and would like a lot of feedback on the setup and most importantly safety tips. Any feedback is welcome. Thank you!