# There's a lot of information online about increasing the strength of an electromagnet with more turns, different cores, etc, but not much about factors in the power supply that affect the strength of the magnet. I've got a commercial electromagnet rated for 12VDC that's supposed to produce 200 lbs of pull. What factors in the power supply will maximize this magnet's strength?

There's a lot of information online about increasing the strength of an electromagnet with more turns, different cores, etc, but not much about factors in the power supply that affect the strength of the magnet.
I've got a commercial electromagnet rated for 12VDC that's supposed to produce 200 lbs of pull. What factors in the power supply will maximize this magnet's strength?
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Bryant Liu
Perhaps the first thing to say is that your power supply should provide dc (direct current), though it need not be 'smooth' dc. Electromagnets don't usually work as well on ac (alternating current).
If the electromagnet itself is not to be redesigned, the only thing you can do to increase its strength is to increase the current through it. The current is proportional to the voltage (potential difference) that you apply (Ohm's law). The relationship is: current = voltage divided by electromagnet's resistance. For example if the electromagnet's resistance is 4.0 ohm, then for an applied voltage of 12 V, there will be a current through it of 3 A (3 ampere).
If you increased the applied voltage, the current would go up proportionally, and the electromagnet might – see last paragraph – pull more strongly. But there would be another consequence. More heat would be generated in the coils of the electromagnet. Suppose that you increased the voltage from 12 V to 18 V (that is by 50 %). Unfortunately the heat generated per second would go up by 125 %. [A formula for heat generated per second is voltage squared divided by resistance.] This could cause problems, even danger. It may well be that the 12 V was chosen by the manufacturers as the maximum safe voltage.
There is another point that's just occurred to me. Beyond a certain current (which may or may not be the current you get when 12 V is applied) increasing the current further will not increase the electromagnet's pull significantly. This is when the iron (or iron alloy) core of the electromagnet cannot be magnetised more strongly, an effect called 'magnetic saturation'.
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Yair Valentine
The strength of an electromagnetic field scales as (number of turns) x (number of amps). The effectiveness of the electromagnet at lifting things has to do with the layout of the pole pieces that "focus" the field into the region of space in which you want the lifting effect to be concentrated. Both ampere-turns and the pole piece design are important.