Current transformers
Finn Hammer, Sat Feb 10 2007, 04:24PMAll,
I now have a Microsim simulation running, which reflects the behavior of a non-linear core. I want to use this to design a current transformer.
This transformer has a centertapped secondary, whereas the primary is just a conductor passed through the center of the toroid core.
Getting close to unity coupling between the 2 secondary windings seems probable, but what about the coupling from primary to secondaries?
Intuitively, it appears as unlikely that this coupling can become particularly high.
Anybody want to share on this topic?
Cheers, Finn Hammer
Re: Current transformers
Steve Conner, Sat Feb 10 2007, 04:41PM
Yes, the coupling between primary and secondaries depends on the permeability of the core, because the core will attract flux from the primary into itself. As a very rough estimate, if the permeability was 1000, the coupling would be 0.999. I think.
Steve Conner, Sat Feb 10 2007, 04:41PM
Yes, the coupling between primary and secondaries depends on the permeability of the core, because the core will attract flux from the primary into itself. As a very rough estimate, if the permeability was 1000, the coupling would be 0.999. I think.
Re: Current transformers
Finn Hammer, Sat Feb 10 2007, 05:23PM
Ok,
I wasn`t aware that the permeability mattered. I only thought it was a matter of getting the windings into close contact with each other.
In a Rogowsky coil, where the (relative) permeability is 1, what coupling is expected, then?
Cheers, Finn Hammer
Finn Hammer, Sat Feb 10 2007, 05:23PM
Ok,
I wasn`t aware that the permeability mattered. I only thought it was a matter of getting the windings into close contact with each other.
In a Rogowsky coil, where the (relative) permeability is 1, what coupling is expected, then?
Cheers, Finn Hammer
Re: Current transformers
WaveRider, Sat Feb 10 2007, 05:29PM
Keep in mind also that coupling will drop as the core saturates.
Coupling is very geometry dependent, so it's difficult to answer your question in a specific way... Certainly, multifilar windings enhance coupling. It is relatively easy to deduce from measurements, tho'...
WaveRider, Sat Feb 10 2007, 05:29PM
Keep in mind also that coupling will drop as the core saturates.
Coupling is very geometry dependent, so it's difficult to answer your question in a specific way... Certainly, multifilar windings enhance coupling. It is relatively easy to deduce from measurements, tho'...
Re: Current transformers
Finn Hammer, Sat Feb 10 2007, 10:06PM
I guess I am expressing myself badly.
I was thinking coefficient of coupling, not coupling.
Cheers, Finn Hammer
Finn Hammer, Sat Feb 10 2007, 10:06PM
I guess I am expressing myself badly.
I was thinking coefficient of coupling, not coupling.
Cheers, Finn Hammer
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