INDIANA

Anyone familiar with the NFPA 79 standard for industrial machinery?

paul d.

hey , indy, maybe you could expand your question a little. sounds interesting already. paul

InControl

Somewhat.

MDShunk

I know that's where I go to look up E-stop information, but that's all I've ever used it for.

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Black4Truck

How is a e-stop different from a regular stop button?

MDShunk

It's got an "E" at the beginning.

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Black4Truck

Thanks Marc.. I figured I needed a "logical" person to explain it to me

Black4Truck

Let me ask this.. if it has been a regular stop all these years, why put an E in front of it now??

macmikeman

Not every (that also starts with an e) stop is an emergency. There is non emergency stops. They don't have an E in front.

INDIANA

I had the facilities guy at my plant tell me that the cord or flex conduit was over the "six foot rule" on some new machines we just installed and that he didnt like the idea of me grounding the transformers back to the building. This guy really pisses me off. Im not perfect and im sure you could find a mistake in something ive done. I try to do my electrical the best I can by the NEC. I had the safety guy order me a copy of the NFPA 79 and one for the facilities guy. I havent recieved the book yet but I do look forward to reading it so I can bust his butt on some of the comments he makes. As far as the NEC 70 goes I told him I didnt write it I just read it!!

TheRick

A Regular Stop is a stop button that stops the machine or process under "regular" conditions, possibly letting a conveyor belt or similar equipment run until empty, or some other portion of the process to complete before stopping.

An E-Stop or Emergency Stop is used in an Emergency situation, and stops everything in the system at once...generally only to be used in an emergency situation, as it may create issues with re-starting the process.

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Rick Boudreau
TASK FORCE SAFE INSPECTION TEAM LEADER
Tal Afar, Iraq
"fool-proof systems do not take into account the ingenuity of fools"

Black4Truck

Thanks Rick for that post.. NOW I understand

wirenut1110

Several things come to mind with an E-stop and a "normal" stop. Most machinery uses dynamic braking for e-stops vs. normal stop.

When you hit the stop button the machine will coast to stop. When you hit the E-stop it will/should stop within around 5 seconds or less through the use of dynamic braking. It is almost like slamming the motor(s) in reverse to stop a machine immediately. Chaps my ass when people would use the e-stop to stop a machine for a normal stop. It puts the equipment into so much shock.

Let's say you have nip rollers or the like on let's say a web machine, when you hit the E-stop, nip points,or any other locations where injury can occur, will reverse because the E-stop doesn't know what the issue is and will stop all nips, pressure, heat, etc. However when you hit the normal stop these points usually need to be manually open.
Most E-stops are NC maintained push buttons, cable stops. E-stops usually have an external push button(mushroom head for example) whereas a normal stop may just have a flush push button and may just be a momentary input to a plc.
That's all I can think of on the subject, hope it helps.

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Jim

leland

NFPA-79

Best I can find in there RE; flex conduit and cable; Is support methods and terminations at,on and in the machine/enclosures.

Length of conduit(flex) falls in NEC.

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"When one American is not worth the effort to be found, we as Americans have lost" (Rolling Thunder MA 1)

foxtek

In packaging equipment we call it a "Cycle stop". The machine comes to a known stopping point after completing the current cycle.
"E Sop" is an emergency stop. The machine comes to an immediate halt no matter what the cycle status is.

M

lectricboy

How is a e-stop different from a regular stop button?


Now that's funny, I don't care who you are.