E-stop wiring and disconnect

[LincHawk]

I have a customer that is installing some new equipment. I will be installing a disconnect for the equipment. It’s 3 phase 208v and 3 phase 480v. They are required to have e-stops for the equipment.

What’s the best way to accomplish this?


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[augie47]

Separate e-stop for each piece of equipment or a common e-stop ?
If you are just stopping motors, an e-stop in the starter control ciruit is common. If you are dissecting ALL power and breakers are involved, shunt tip breakers might be an option.
We need a lot more detail for a realistic answer.

 

[LincHawk]

Running a feed to each piece of equipment. Obviously it needs a disconnect but they require a e-stop for each piece of equipment.


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[jim dungar]

Some people consider a simple mushroomhead pushbutton as an e-stop. Others require an e-stop circuit that disables all sources of power to a machine or process, including hydraulics and pnuematics. Still others demand an e-stop circuit with dedicated safety relays that perform self checking functions.

You probably need to ask more questions of the customer.

 

[tom baker]

If there is a control panel for each motor, then an e stop can ne added to that, can also have remote estops. Estops typically have a control relay wired to the button. A common estop for all equipment is. more involved

 

[LincHawk]

There is nothin there. I’m building this from scratch. So I need a disconnecting means and a remote e stop for each piece of equipment. So I guess building a control panel is the route to go?


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[Coppersmith]

Aren't e-stops wired in series with the stop button on the starter circuit. Of course, that just provides a stop. There is not emergency procedure performed like braking.

 

[jim dungar]

Aren't e-stops wired in series with the stop button on the starter circuit. Of course, that just provides a stop. There is not emergency procedure performed like braking.

A stop button may have some type of timing associated with, like a VFD needs to ramp down to zero speed or simply a motor coasting to a stop.
A true E-Stop should bring the machine to a screeching halt, with no intentional time delay, and may even require braking mechanisms.

I suggest looking at NFPA79 for a good listing of the various types of 'stopping' that might be applied to a machine.

 

[Jraef]

It seems as though you might be unsure how to implement an e-stop and just a disconnect. Although possible, it’s not probable. An e-stop is generally associated with a motor starter or controller. If you don’t have one, you will need to add one. If the machinery comes with a starter, you need to do is find the coil circuit and implement the e-stop there. There is a lot more to it than that, you need to discuss it with all of the stakeholders involved; not just the purchaser, but also the operators, production manager, safety officer, etc. having a safe workplace is not a flippant thing that they can dump responsibility for into you. Your job is to implement it, maybe design it if they have a stated procedure, but they are ultimately still responsible and must be involved.

 

[LincHawk]

It sounds like a motor starter is a good route to go with this. I would be getting approvals on what I ultimately do. I’m still gathering info to determine the best route to go with this. Safety is #1 priority always


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[tom baker]

I have done lots of motor control over 35 years, have built and purchased motor controllers. Compared to building a motor controller, purchasing is about the same price, as the fab shops get a better discount, you get a materials list, drawings, and most important, UL508 listing. In Washington, if the panel is not UL listed, the job stops.
There is a lot to consider, fuse, circuit breaker, NEMA,, IEC, so please consider getting a panel shop in involved due to the liability. Then you just run the feeders..

 

[SIE Electrician]

The machine typically has controls. What is the equipment?