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1.5T DC Magnet design advice

1.5T DC Magnet design advice

(OP)
I am developing a design for a DC Electromagnet being used as an electromagnetic brake. Here is a picture of my design that is modeled in FEMM. I would like some advice to see if there were some modifications I could make to increase my flux density between the pole tips. I am using 1018 Steel and both windings are currently designed with 14 AWG at 255 turns and a current of 100A. This will be a pulsed magnet with a very low duty cycle, less than 1/2 seconds. Unless I can find a better quality steel such as 1008 or 12L14 for the same price and stock size, I am stuck with 1018 for now. So far in my design the magnet is 5 inches high, 5 inches wide, and will be 12 inches in length. The pole gap can't be smaller than 1/2in.

We are looking to have a maximum field strength on the order of 1.5T between the pole tips. However with 14 AWG this would require me to use a at least a 170VDC power supply connected to a capacitor bank to provide the high pulsed current, since I would need to pulse nearly 100A through the windings. So far I have experimented with 16AWG and 18AWG. Though I would be using less current, the increased number of windings and increased resistance make things even more prohibitive due to the need for much higher voltages. Is there a way I can alter my design - either the windings or the magnet geometry so that I wouldn't need to use as much current?

Here is a picture of my model on FEMM 4.2




RE: 1.5T DC Magnet design advice

increasing turns or current, and changing to 1008, cannot help much to get you a higher flux density at the gap. 255 turns, 100A for such an electromagnet can give you an exciting field of about 1000 Gs (Oe). This field can almost saturate any of your pole pieces.
if you cannot decrease the gap, the only option i can think of is to redesign the circuit. you need at least to design a returned flux path to decrease the flux leakage

RE: 1.5T DC Magnet design advice

I appologize for saying that increase in A.N cannot help to increase B.

The H field i calculated was about 1000Oe, under which the permeability of the core material will be low at about 20. If ignoring the reluctance of the core, the B field, using N.A = 25500, air gap =.5'', area = 5x5 Sq. inch, was about 2.5T!

However, due to low permeability, the reluctance of the core is comparable to the air gap, or even larger. we can not ignore the relutance from the core material. So increasing the area of core at the coil (not the area of air gap) and decresing the path length will effectively decrease the total reluctance, and therefore, the flux density will be increased.

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