Post by antigua on Feb 20, 2017 21:07:39 GMT -5
There was a discussion about neodymium saturating steel cores to the point of lowering inductance over on the TDPRI forum; and since this is a good investigation into the working of pickups, I'm reposting my contribution here, lest it get lost in the ether at TDPRI...
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The pickup with steel six cores shows 3.961H @ 120Hz:
With six neodymium bottons over the slugs the inductance showed 3.960 when I took the picture, but this number bounces around by +/-3 mH as I jiggle the wires, so the inductance is effectively the same, and so they must not be saturating the core.
But then I stuck a giant neodymium over the pickup, one that has many more times the flux density of the buttons, and the inductance drops to 3.269 henries, so it does appear that the larger neos saturate the core somewhat:
Note that with no steel cores at all, the inductance drops below 2 henries, as this is a typical Strat pickup with about 6k ohms worth of windings. At 3.269 henries, this pickups still has far more inductance than one with air cores, or even one with AlNiCo cores, so the core is not saturated to the extent that it performs like air. I do not know whether this means there is only partial saturation, or if a partial loss of inductance is to be expected (relative to air core) when a core reaches complete saturation.
~~*~~*~*~*~
The pickup with steel six cores shows 3.961H @ 120Hz:
With six neodymium bottons over the slugs the inductance showed 3.960 when I took the picture, but this number bounces around by +/-3 mH as I jiggle the wires, so the inductance is effectively the same, and so they must not be saturating the core.
But then I stuck a giant neodymium over the pickup, one that has many more times the flux density of the buttons, and the inductance drops to 3.269 henries, so it does appear that the larger neos saturate the core somewhat:
Note that with no steel cores at all, the inductance drops below 2 henries, as this is a typical Strat pickup with about 6k ohms worth of windings. At 3.269 henries, this pickups still has far more inductance than one with air cores, or even one with AlNiCo cores, so the core is not saturated to the extent that it performs like air. I do not know whether this means there is only partial saturation, or if a partial loss of inductance is to be expected (relative to air core) when a core reaches complete saturation.
