Machinery Safety 101

Testing Emergency Stop Systems

This entry is part 11 of 16 in the series Emer­gency Stop

I’ve had a num­ber of ques­tions from read­ers regard­ing test­ing of emer­gency stop sys­tems, and par­tic­u­larly with the fre­quency of test­ing. I addressed the types of tests that might be needed in…

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Safe Drive Control including Safe Torque Off (STO)

Graph illustrating STO Function
This entry is part 12 of 16 in the series Emer­gency Stop

Ed. Note: This art­icle was revised 25-Jul-17 to include inform­a­tion on safe stand­still. Safe Drive Con­trol includ­ing STO Motor drives are every­where. From DC vari­able speed drives and index­ing drives,…

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Emergency Stop Failures

This entry is part 13 of 16 in the series Emer­gency Stop

I am always look­ing for inter­est­ing examples of machinery safety prob­lems to share on MS101. Recently I was scrolling Reddit/r/OSHA and found these three real-world examples. Broken Emer­gency Stop But­tons The…

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Emergency Stop Pull-Cords

This entry is part 15 of 16 in the series Emer­gency Stop

This art­icle was updated 2020-06-13, adding links to the Rock­well Auto­ma­tion and Schmersal pull-cord data, and on 2019-04-26, adding spe­cif­ic details related to IEC 60947 – 5‑5 [7]. When it comes to…

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Can Emergency Stop be used as an “on/off” control?

Emergency Stop Button
This entry is part 16 of 16 in the series Emer­gency Stop

Every couple of months I get an email ask­ing me if there is any reas­on why e‑stop func­tions can­’t be used as the primary power con­trol (on/off but­ton) for machinery. Fol­low­ing…

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More E‑Stop Questions

This entry is part 17 of 16 in the series Emer­gency Stop

Here are some more ques­tions I’ve been asked regard­ing emer­gency stop require­ments. These ones came to me through the IEEE PSES EMC-PSTC Product Com­pli­ance For­um mail­ing list. Primary Sources There…

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