Author Topic: Short-Circuit Protection of Relay, i2t Rating  (Read 880 times)

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Offline AltiTopic starter

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Short-Circuit Protection of Relay, i2t Rating
« on: May 10, 2020, 08:36:45 pm »
Whenever I want to use a thyristor or triac, the short-circuit protection is one of the parameters considered and i2t for fusing is given in every triac datasheet. Including survivability charts for Itsm. I know how to deal with that. Also contactors have the peak short-circuit current specified (in kA).

What about an electromagnetic relay?
I have an application where there might be a short circuit in a mains powered circuit that includes a relay in a loop. I imagine a scenario where the relay is already closed, bad luck happens and some other componet fails. This causes the current to increase in microseconds to some peak value. I am using a 80A2s fuse, this guarantees limited peak current (lets say 500A peak) and limited i2t (lets say 200A2s) but I just wonder if this is adequate for a closed 16A relay.. I do not intend to interrupt the short circuit with a relay but with a fuse, once the component that failed is fixed and fuse replaced, I expect this relay to continue operation, with some predictable lifetime reduction.

Any hints?

Relay example:
Schrack 41083 www
Link to datasheet.
« Last Edit: May 10, 2020, 10:16:15 pm by Alti »
 


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