# Inductor Question

#### woody

I have a 70mh 2A inductor. Could I remove about 1/2 of the windings thus
lowering the inductance to about 17.5 mh and increase the Amp rating to
3A or more ? This would be for a choke input suply where I need a minimum
of 3A and 7 mh so should this work ?

#### newvirus2008

Yes, H = NI / l, so decreasing N while increasing I (by the same amount) keeps H (and B) the same. However, increased ampereage also requires an increased wire thickness, so you may have to rewind for J = 3A / sq mm (typical). If J is already satisfied (or the 3A is not continuous), then you just need to adjust the turns, and that's it.

Thanks

#### Mark Tillotson

I think 2.7A is practical - you've reduced R by a factor of 2, so can increase I by √2 for the same wattage, but a smaller winding has somewhat less surface area to lose heat through, so perhaps 2.7A is going to cause the same heating?

The other reason for a current rating is saturation, reducing the turns by 2 allows doubling the current if that's the only reason, but we'd better assume power dissipation also matters.