Phase-protection fuse

[Moskoskos]

Hi.

I'm currently working as an apprentice within automation engineering.

It has come to my attention that there are a lot of different fuses and motor-protectors in this profession, and I don't even know the half of it.
So I'm wondering if anyone of you might be able to help me with a question.

I'm wondering how a phase-protection fuse works.
My translation might be wrong but I'll try to explain.

The fuse I'm talking about is not protecting against overload/over current or short-circuit. Its basically "monitoring" all the phases and if one of them were to disappear the fuse would automatically disconnect.
I've read that the differential between the phases should be 0V or within a specific voltage given.

Anyone whom may clarify?

Regards
Atle.

Also, if anyone got time it would help alot if anyone explained how a under-/over-voltage fuse works.

 

[jraef]

That yould not be a "fuse", a fuse is something that melts and is not resttable.

You want what is called a Phase Monitor Relay. Search on that tewrm.

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[magoo2]

There have also been some triggered fuses where all 3 fuses would operate for any type of fault condition. It might even work for loss of voltage but I don't remember if it did. I think Phoenix Electric did some early development with this concept.

 

[Moskoskos]

Aha.
I'll look into that.

Thank you for the quick replies