Off-the-shelf electromagnet with deterministic pole

Question

I looking to buy an electromagnet (12v) and there are a lot of them out there on amazon and ebay in all kinds of size and shapes -some are round, some are rectangle, etc. However, in my application, it's important that I have a positive side of the magnet facing out when the current runs through the electromagnet. In my application, I'm utilizing the repel effect of two magnets where another piece has a permanent magnet with positive side facing out. So the goal here is that when the electromagnet is energized, we have a force that pushes the two magnets away from each other.

For example, in this picture with this DC electromagnet, is it as easy as changing the polarity of positive and negative to get, say the positive side on its face? The specs that I ready don't mention anything about that. Thanks in advance.

Answer 1

To change the polarity of the magnetic field, all you have to do is change the polarity of the input current.

However, what you've shown there is a 'pot' magnet, with both poles on the same face. If you want to set up repulsion between two magnets, you'd do better with solenoids, that have a pole at each end. The geometry will be easier, as pot magnets really need to be axially aligned and have similar sizes to repel. Otherwise you end up attracting the metal of the outer shell, regardless of what the inner pole is doing. With a pole at each end, you can use very different sizes, use in conjunction with permanent magnets, use off axis, it's much easier.