Power Generated by a Toroidal Current Transformer

[z0dE]

I'm building various current transformers for a project at work and having trouble finding out what the best core material is to generate the most power from a 7kV power line using inductance. I have seen that Silicon-Steel provides the greatest flux density saturation but have heard that some ferrite cores can generate much higher power output levels. Now comes the greatest problem, the core total weight must be less than .5 pounds.

Can someone point me in the right direction?

 

[berkeman]

Do you mean like from a 50/60Hz power line? I don't think you would use ferrite for that -- ferrites are typically used for high frequency transformers, because it is not practical to use steel layers that would be thin enough to prevent significant eddy current losses.

Probably whatever is used in typical AC mains power transformers would be the best. What materials are used in power company transformers? (I don't know offhand, but could probably find it with a wikipedia.org or google search)

 

[z0dE]

Do you mean like from a 50/60Hz power line?

Right, looking around at some manufacturers, I found that a 3% composition Si-Fe is quite good for that but also so is a 50% Co-Fe composition. Would there be any excessive heat to worry about when selecting a core material or casing material coming from a 7kV line, if I were to step it down to about 10.0 V, I know the ~60A primary current will be significantly higher in the secondary but will it be too much heat for the transformer to operate effectively?

 

[berkeman]

I'm probably not going to be of much help on this one. But the total heat will be the sum of the resistive wire losses (7kV down to 10V?) and the eddy current losses in the laminated core.