# Help with electro magnet

• May 13th, 2013, 08:03 PM
johnwashburn1
Help with electro magnet
i have a question hopefully someone can help me with. I need to construct an electro magnet that has a repelling force of 700-800lbs. the catch is that it cannot be larger than 5in in diameter length can be no longer than 24in. Is this possible? If so could you give me the size, number of wraps, and the required voltage to achieve this in short repetitive pulses.
• May 13th, 2013, 10:10 PM
Howard Roark
Quote:

Originally Posted by johnwashburn1
i have a question hopefully someone can help me with. I need to construct an electro magnet that has a repelling force of 700-800lbs. the catch is that it cannot be larger than 5in in diameter length can be no longer than 24in. Is this possible? If so could you give me the size, number of wraps, and the required voltage to achieve this in short repetitive pulses.

See here. You need to decide on one more variable, the permitivity of the core.
• May 14th, 2013, 12:03 AM
johnwashburn1
thanks so much for the reply. i may seem like an idiot but i am having trouble calculating, this is a theoretical EM, so what ever material would achieve the results will be what's used. I want to make this portable so lets say a car battery 12.6volts (est. 12amps). i guess i'm asking for a result and need some help getting to it. Use your imagination and tell me how to construct the EM. again thank you so much.:lol:
• May 20th, 2013, 12:15 PM
fizzlooney
Try here---www.rexresearch.com/mrmagnet/Non-Ferrous-Magnet.pdf. BTW magnets attract ferromagnetic materials not repel them . 700 lb pull will require a large one
• May 23rd, 2013, 12:38 PM
johnwashburn1
I want to push a permanent magnet with the EM, this would create a repelling force. the permanent magnet is 4 inches in diameter and about 3 inches thick.