# Reversing magnet polarity to increase/decrease Eddy currents?

I have a cast iron wheel with magnets around the inner radius as a braking mechanism. If I were to add additional magnets around the outer radius, would the amount of Eddy currents increase or crease if the polarity of the outer magnets was opposite?

EDIT:

Here's a diagram

where black circle, red and green rectangles depict the wheel, existing magnets and new magnets, respectively. The existing magnets have the S side facing the wheel. So my question is, if the green magnets have the N side facing the wheel, will Eddy currents increase or decrease? What if the S sides face the wheel? In fact, do the polarities of any of the magnet matter?

• Can you include a diagram? There are a few different ways to interpret this. – rob Sep 23 '18 at 6:32
• @rob Sure. I've drawn something up which I hope is understandable. – John M. Sep 23 '18 at 6:43
• If you increase the magnetic field in which the conducting wheel moves then this will increase the induced emf, the eddy currents and hence the braking effect. – Farcher Sep 23 '18 at 8:05
• Related question by same user : Increasing Eddy current induced within surface by attaching a magnet on surface – sammy gerbil Sep 23 '18 at 9:41

If the magnets in the two sets were facing each other (i.e., if green outer magnets were shifted to the $$6$$ o'clock position), it would be pretty obvious that, in order to increase eddy currents, the outer magnets would have to be installed with their north poles facing the wheel, so that the magnetic fields of the two sets boosted each other rather than canceled each other.
When the outer magnets are located as shown on the diagram (at about $$3$$ o'clock), the interaction of the magnetic fields of the two sets is not as significant.