core saturation

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I was just thinking about core saturation and how it might be
detected/measured and I remembered something about current transformers
being ruined if they were allowed to saturate. Am I remembering
correctly? Previously I had been thinking that saturation was a
harmless event -- if currents were limited. Yes or no?

Thanks

 

[John Larkin]

I was just thinking about core saturation and how it might be
detected/measured and I remembered something about current transformers
being ruined if they were allowed to saturate. Am I remembering
correctly? Previously I had been thinking that saturation was a
harmless event -- if currents were limited. Yes or no?

Thanks

You can magnetize a CT by running it without a burden resistor, and
that will subsequently mess up low-current accuracy. But it's easy to
demagnetize it and fix it.

In an extreme case, I guess you could arc it over or something, but
that's not common.

 

[John Popelish]

I was just thinking about core saturation and how it might be
detected/measured and I remembered something about current transformers
being ruined if they were allowed to saturate. Am I remembering
correctly? Previously I had been thinking that saturation was a
harmless event -- if currents were limited. Yes or no?

Thanks

Core saturation is normally a reversible process.

 

[Rich Grise]

I was just thinking about core saturation and how it might be
detected/measured and I remembered something about current transformers
being ruined if they were allowed to saturate. Am I remembering correctly?
Previously I had been thinking that saturation was a harmless event -- if
currents were limited. Yes or no?

It doesn't ruin the transformer - it ruins the waveform and you get
an inaccurate answer.

And in a current transformer application, the primary current is limited
by the load itself, so that's certainly not a problem, but do pay
attention to that burden resistor!

Good Luck!
Rich