## Polarity switching electromagnet

I wanna make an electromagnet to rapidly switch polarity back and forth. I hear the core should be made of laminated iron to avoid heat losses; is this correct? Where could I get one such core from, and is there anything else I should consider?
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 Well since power transformers are laminated and do switch polarity efficiently, I would suggest you look around for surplus, burned out or otherwise unwanted power transformers and take your parts from that. (you can use the copper wire if you can get it out in usable lengths.) AC electric motors have laminated cores also. You are familiar with the problems involved in driving an inductive device with a switched signal with a fast rise time? DC

 Quote by DarioC You are familiar with the problems involved in driving an inductive device with a switched signal with a fast rise time?
Eddy currents and heat losses? Is there anything else?

Recognitions:
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## Polarity switching electromagnet

 Quote by dorker Eddy currents and heat losses? Is there anything else?
In a circuit with inductance, current exhibits a reluctance to undergo any rapid changes. The more rapidly you try to make it change, the more stubborn it becomes.

The inductor equation, v=L.di/dt shows that if you want a high value of di/dt, you have to apply a high v.