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I am currently working with software for a safety relay and during my work I started to think about how much time it takes for a relay to switch.

The relay and it's data sheet I am using can be found here: http://www.digikey.com/catalog/en/partgroup/sr2m-schrack-series/960

Can somebody help me understand how to calculate the time for this relay to toggle when it has maximum current load (6A)? Considering the worst case scenario.

I suspect that the parameter "Frequency of operation, with/without load 6/300min-1" have something to do with my question but I can't understand it.

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I assume you mean how long will it take the relay to open and interrupt power to its load. I'm not sure if that 300/minute spec holds the answer to the question, but it does suggest an upper limit of maybe 100 ms. In practice it depends quite a bit on what kind of coil suppression is used. For more info see: http://www.cbxelectronics.com/pdf/app-notes/app-note1.pdf

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The "frequency of operation" specification doesn't have anything to do with how fast the relay operates; it's only related to the contact lifetime under various operating conditions.

The datasheet doesn't give any data related to the speed of operation. You'll need to talk to an applications engineer from the manufacturer, since it depends very strongly on things such as drive level, spring strength (and its tolerance), coil inductance, etc.

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The frequency of operation is indeed what you need. You should read it as 6 cycles per minute with load, 300 cycles per minute without. So at 6A switching on+off should take at least 10 seconds (1/6 of a minute).

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  • \$\begingroup\$ I think you misunderstood the question. \$\endgroup\$ – Dave Tweed Nov 11 '13 at 16:15

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