inductance of a solenoid with ferrite rod core

Similarly for smaller E-I or U-I cores the assembly can be carried out such that the gaps are staggered every other lamination. 25) For large power transformers the laminations are cut in a specific way to accommodate such overlapping.

If a transformer core is made of laminations, then they are cut and assembled in a way as to stagger the gaps, to minimise any localised effects. Through the increase of magnetising current.

The air gap lowers the total inductance of the primary winding and causes an increase in apparent power 25) All these factors impact efficiency of energy transformation. Laminations in larger transformers are overlapped to distribute the air gap 24) by United States Patent and Trademark Office, Public DomainĪny air gap in the magnetic core increases leakage inductance and stores additional energy, which needs to be cyclically transferred or dissipated. Such cores are usually more expensive (either in initial production or further coil winding) than alternative technologies with a single gap. The fringing effect and leakage flux is greatly reduced, which is especially important for high-frequency applications. The resultant effective permeability is much lower, but the air gap is uniformly distributed throughout the whole material. There are magnetic materials, which are made from small particles (mostly based on powder iron, sendust or moly permalloy powder) bound together in such a way as to contain certain percentage of non-magnetic volume in them. The distribution of air gap can be also extended even further. In order to reduce the flux fringing effect and the losses associated with it, in some inductors the gap is distributed into many smaller gaps. In such case a so-called “ air core” is used, where the windings are supported by a non-magnetic structure, and the whole magnetic circuit is effectively one big air gap. In some cases the currents are so high that it is very difficult or cost prohibitive to design the inductor with a magnetic core. The magnetic field lines must close through the surrounding air (outside of the winding), so the length of the air gap is comparable with the length of the rod.

For instance, a common design for electronic chokes is to place a winding on a magnetic rod. If operation with high currents is required then the air gap might be very large, so that the magnetic circuit is quite “open”.

Inductance of a solenoid with ferrite rod core