Saturable Reactors: Power Control with Permanent Magnets

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Saturable reactors, or magnetic amplifiers, control AC power by varying the saturation of the core around which the AC coil is wrapped. The discussion highlights that while saturation can increase power transfer in certain configurations, it also reduces energy transfer in transformers by diminishing the flux linking to the secondary coil. When a non-magnetic core is used with an AC coil and exposed to a permanent magnet, the expected behavior is a decrease in efficiency, similar to holding a magnet up to a transformer, which disrupts its operation. The B-H curve illustrates that as saturation occurs, the relationship between magnetic flux density and magnetizing force becomes non-linear, leading to reduced energy transfer. Overall, the effectiveness of magnetic amplifiers depends significantly on the core material and its saturation level.
Jdo300
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Hello,

I've been doing some research into antiquated Magnetic amplifiers. From what I understand, one can use a mag amp to control the power of an AC field by varying the saturation level of whatever core the AC coil is wrapped around (basically). I know that this can be accomplished by using a type of transformer where the control coil is pulsed with DC at varying levels to control the AC coil.

My question is that if it is the magnetic field that controls the power level of the AC signal, and the more saturated the core, the more power can get through. What would that same AC coil do if you wrapped it on a non magnetic core and exposed it to a magnetic field from a permanent magnet placed in close proximity to the coil?
 
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I'm not familiar with mag amps per se, but when you saturate the core of a transformer, you reduce the transfer of energy from primary to secondary, not increase it. Look at the B-H curve for magnetic material...As you get into saturation, the B does not increase in proportion to H anymore. It increases more slowly. That will reduce the flux linking to the secondary coil, compared to what you would get if the material were not saturating.

If you hold a magnet up to a transformer, the transformer does not work well at all.
 
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