Discuss Does a 20amp emergency stop button exist? in the UK Electrical Forum area at ElectriciansForums.net
No I think they require just a stopWelcome to the forum mate.
Who has asked for an "Emergency Stop Button"?
Has it got to be an "Emergence" stop button or just a stop button?
The reason why I ask is if you are fitting an "Emergency Stop Button" to a circuit you have to do a risk assessment to determine what category of Emergency Stop is required. There is a lot more to it than just bunging in a stop button.
No I think they require just a stop
Button for quick isolation. It’s for a training environment.
You are missing the point.
Just noticed you need 20amp, you may need to add a contactor.
Safe torque off (STO)Responding to the input signal from external equipment, the STO function shuts off power to the servo motor electronically using the internal circuit (shuts off through secondary-side output). This function corresponds to the Stop category 0 of IEC/EN 60204-1. | |
Safe operating stop (SOS)This function monitors the position of the servo motor not to deviate from the specified range. Power is still supplied to the servo motor during the SOS function. | |
Safe direction (SDI)This function monitors whether the servo motor moves in the command direction. If the servo motor moves in a different direction from the command direction, the STO function is executed. | |
Safe stop 1 (SS1)Responding to the input signal from external equipment, the servo motor starts to decelerate. After the set delay time for the motor stop is passed, the STO function starts. Monitoring the servo motor deceleration based on the motor deceleration rate is also supported. This function corresponds to the Stop category 1 of IEC/EN 60204-1. | |
Safe brake control (SBC)The SBC signals are outputted for external brake control. | |
Safely limited increment (SLI)This function monitors the travel distance of the servo motor not to deviate from the specified range. If the travel distance exceeds the range, the STO function is executed. | |
Safe stop 2 (SS2)Responding to the input signal from external equipment, the servo motor starts to decelerate. After the set delay time for the motor stop is passed, the SOS function starts. Monitoring the servo motor deceleration based on the motor deceleration rate is also supported. This function corresponds to the Stop category 2 of IEC/EN 60204-1. | |
| Safely limited speed (SLS)This function monitors the speed of the servo motor not to exceed the specified speed limit. If the speed exceeds the limit, the motor power is shut off by the STO. |
Safe speed monitor (SSM)The SSM signals are outputted when the speed of the servo motor is below the specified speed limit. | |
Safely limited torque (SLT)This function monitors the torque (or the thrust) of the servo motor not to deviate from the specified range. If the torque (or the thrust) exceeds the range, the STO function is executed. |
I'm not missing the pointYou are missing the point.
An Emergency Stop, depending on its use and risk assessment of its purpose may need to be far more than just a switch with a red button on the end of it.
Adding a contactor, can make the system less safe than a direct switch as you have no way of knowing if it is going to disengage when needed.
as above, there are different categories of emergency stop systems and it needs to be decided what category of stop system needs to be designed and installed.
If you have little knowledge of industrial control systems and emergency stop systems, you would be well advised to pass up the job for your own good.
YesSo it's for isolating the power to a training area?
You are missing the point.
An Emergency Stop, depending on its use and risk assessment of its purpose may need to be far more than just a switch with a red button on the end of it.
Adding a contactor, can make the system less safe than a direct switch as you have no way of knowing if it is going to disengage when needed.
as above, there are different categories of emergency stop systems and it needs to be decided what category of stop system needs to be designed and installed.
If you have little knowledge of industrial control systems and emergency stop systems, you would be well advised to pass up the job for your own good.
Sorry, but you are.I'm not missing the point
I'm aware of different types of emergency stop systems
But he said:
j_arney said:
No, I think they require just a stop
Button for quick isolation. It’s for a training environment.
Sorry, but you are.
A training environment may well bring in added risks that are not there in the normal working environment.
I.e. In the work environment, if you are to be working on electrical systems you should have a good grasp of safe isolation and testing procedures.
In training, mistakes happen and the idea of an emergency stop is a good one.
however, if the training risk assessment relies on the fact that an instructor can kill the power if a danger appears and therefore reduces or removes that danger.
IT MUST HAVE A REALLY GOOD CHANCE OF WORKING CORRECTLEY!!
we do not know what the risk assessment is or how serious it may be if the emergency stop button fails to function when required so we should not be advising on how to do it.
Yes you can get a bench saw switch, I'm sure there are others thoughAppreciate all the info, but I just wanted to know if you could get a 20amp stop button. Do you know the answer to that?
j_arney said:Sorry, but you are.
A training environment may well bring in added risks that are not there in the normal working environment.
I.e. In the work environment, if you are to be working on electrical systems you should have a good grasp of safe isolation and testing procedures.
In training, mistakes happen and the idea of an emergency stop is a good one.
however, if the training risk assessment relies on the fact that an instructor can kill the power if a danger appears and therefore reduces or removes that danger.
IT MUST HAVE A REALLY GOOD CHANCE OF WORKING CORRECTLEY!!
we do not know what the risk assessment is or how serious it may be if the emergency stop button fails to function when required so we should not be advising on how to do it.
Thanks for your help. I think the contactor route will be better!Yes you can get a bench saw switch, I'm sure there are others though
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Yes you can get an emergency stop button that is rated at 20A,
however by fitting it you run the risk of being in court for corporate manslaughter or a number of other nasty legal challenges to your freedom.
in my opinion, after re reading what i have posted, i think the advice is sound.
you are of course free to take it on board and use it or ignore it.
Fair point, however I have never seen a training environment where the "training is wire up this spar pump"You are being ridiculous, you have no idea what he's switching it, maybe a spa pump for instance.
He simply asked if they did a 20 amp stop switch, and you accused me of missing the point, when in fact it was you who missed the actual question.
Fair point, however I have never seen a training environment where the "training is wire up this spar pump"
like I said, if the risk assessment deems it suitable then go ahead but i think it is a vital step that both you and the op are missing.
OP, has anybody done a risk assessment and if so, what stop category are you trying to design. also, is a single point of failure likely to bring a risk of significant harm to anybody?
I am done with this for tonight and my final thoughts are Simpley that on the face of it neither @mainline or @j_arney have the information and knowledge required to design a suitable safety system for this project.
As opposed to arguing the right and wrongs, what is your background.You have no idea what the project is ... and you deem it that neither me or the op have the knowledge required ???
Are you for real or is it that you can't stand the fact that you were wrong.
I also take umbrage at you saying I lack the knowledge when you have no idea what my background is.
I worked in electronics and programming for over 40 yrs before semi retirement and now work to suit mostly repairing various radio test equipment from all over the world, for 3 days a week i look after 21 cottages on a holiday complex mostly electrical.As opposed to arguing the right and wrongs, what is your background.
Love the workshop.I worked in electronics and programming for over 40 yrs before semi retirement and now work to suit mostly repairing various radio test equipment from all over the world, for 3 days a week i look after 21 cottages on a holiday complex mostly electrical.
Things like this but now more as a hobby
You have no idea what the project is
With all respect to the conversation, your premise of ridiculous is not founded by any of the posts, we simply do not have the info to make such accusations, if this is for course work then we don't permit direct answers only nudging but is this is real then we indeed need to question the context of his circumstances because this falls in a category that information is crucial to responses.You are being ridiculous, you have no idea what he's switching it, maybe a spa pump for instance.
He simply asked if they did a 20 amp stop switch, and you accused me of missing the point, when in fact it was you who missed the actual question.
a point that has been missed so far, unless i've missed it, is that a stop button is wired into the control circuit, so no way will it ever see a 20A load current.
This is why the op was asked what the stop button was for and advised that its not as simple as just wiring in a "stop button". would have been just easier to search on google for the 20amp switch, than ask on this forum, if there is no intent on taking advice or explaining what the job is.a point that has been missed so far, unless i've missed it, is that a stop button is wired into the control circuit, so no way will it ever see a 20A load current.
This is why the op was asked what the stop button was for and advised that its not as simple as just wiring in a "stop button". would have been just easier to search on google for the 20amp switch, than ask on this forum, if there is no intent on taking advice or explaining what the job is.
Yeah, but is an unusual request so quite rightly raised interest in what it was required for.That's what the op did, he said he basically just wanted to know if a 20 amp stop switch existed, as he couldn't find one.
I get the questions being asked concerning a risk assessment, but the op a number of times said that he just wanted to know if one existed and wasn't interested in anything else.
I'm sure if he is learning in a training environment, then the trainer will put him right.
If the op returns, then maybe he can explain the scenario.
That's what the op did, he said he basically just wanted to know if a 20 amp stop switch existed, as he couldn't find one.
I get the questions being asked concerning a risk assessment, but the op a number of times said that he just wanted to know if one existed and wasn't interested in anything else.
Dear mainline,I worked in electronics and programming for over 40 yrs before semi retirement and now work to suit mostly repairing various radio test equipment from all over the world, for 3 days a week i look after 21 cottages on a holiday complex mostly electrical.
Things like this but now more as a hobby
Thanks for the kind wordsDear mainline,
I gather Gibsons jigsaw company are looking for a suitable picture to continue their ‘workshop‘ category of puzzles.
Thank you for the great photos of your lab bench. It clearly is a place where work is indeed done.
Regards
Marconi
View attachment 99430
Fair point, however I have never seen a training environment where the "training is wire up this spar pump"
like I said, if the risk assessment deems it suitable then go ahead but i think it is a vital step that both you and the op are missing.
OP, has anybody done a risk assessment and if so, what stop category are you trying to design. also, is a single point of failure likely to bring a risk of significant harm to anybody?
I am done with this for tonight and my final thoughts are Simpley that on the face of it neither @mainline or @j_arney have the information and knowledge required to design a suitable safety system for this project.
Hey
Im back and done the job. In the end I had a 6amp circuit feeding the stop button then the coil and 20 amp circuit supplying a socket via a rotary isolator and contactor.
I hope you have not seen my comments as either negative or condescending.Hey
Im back and done the job. In the end I had a 6amp circuit feeding the stop button then the coil and 20 amp circuit supplying a socket via a rotary isolator and contactor.
So you had a stop button and rotary isolator switching the socket on and off. I was asked to do this for a colleague at one of our sites and have no idea what he intends to do with this system. He’s designed it, he’s an engineer and I haven’t asked any questions. I can totally understand the repercussions from making mistakes in certain working environments and appreciate all the feedback. I’m on this forum to hopefully learn a bit, but sometimes there’s no need for some of the negative/ condescending replies.
Then one MCB safely isolates the lot. It sounds as though you'd have to turn off two MCB's for everything at the contactor to be safely isolated?
If this is paid work and invoiced you better have a paper trail of proof to who designed it and takes responsibility otherwise it still falls at your feet, imagine is someone is injured or worse, do you expect them to put their hands up to possible dangerous installation practices or point the finger at you showing your invoice.
If you are invoicing it it would be an idea to make it part of the invoice declaring no responsibility for design or safety making it clear it was requested, this would not remove you from and possible legal action because unless you have a full paper trail to this the responsibility lies on you to assess any requests meet standards applicable, so tread carefully I
i did consider that option, I don’t regularly install contactors and seen it done that way a few times before. Will take on board thoughThis is intended as a constructive comment. Where possible I would have fused down the 20 amp circuit for the coil. Then one MCB safely isolates the lot. It sounds as though you'd have to turn off two MCB's for everything at the contactor to be safely isolated?
A Mcb does not provide safe isolation, especially on a TT earthing system
After all, we wouldn't want the OP thinking that It's OK to do so he could end up killing someone
Have a look for a NVR switch (No Volt Release) they are on most woodworking machines that can cary high loads, this one is rated at 18amp: Axminster Workshop KJD17B NVR Switch 230V 1ph - https://www.axminstertools.com/kedu-kjd17b-nvr-switch-230v-1ph-102532?queryID=caac039e86bf11f04a93756c659eea3eI’ve been asked to provide an emergency stop button for a circuit rated at 20amps. I’ve never installed one before and only really found 10amp buttons at my local wholesaler. I can put a contactor in, no problem but was just interested to see if you can get them?
Yes I get the " I wasn't meaning safe isolation when I said safely isolatedI think you know my point was really about multiple sources of supply.
( I'll take your point that an MCB isn't always suitable for isolation. It isn't as simple as saying it never is though - after all if that were the case it wouldn't appear in table 537.4 with a "Yes". )
And to be clear, I wasn't meaning to refer to "safe isolation" in the sense of the procedure to ensure it is safe to commence working. I said "safely isolated", maybe unwise words but I meant there are two things to turn off not one, a trap for the unwary and reg 537.1.2 could be worth considering.
Have a look for a NVR switch (No Volt Release) they are on most woodworking machines that can cary high loads, this one is rated at 18amp: Axminster Workshop KJD17B NVR Switch 230V 1ph - https://www.axminstertools.com/kedu-kjd17b-nvr-switch-230v-1ph-102532?queryID=caac039e86bf11f04a93756c659eea3e
Its not nvr but looked the same at first glance #13Can't find any reference to an NVR at the beginning of the thread, can you post a link?
It was in relation to does a 20 amp stop switch exist.An NVR has an additional level of protection, and that link is to a unit that is not available, so not much use to the OP.
Reply to Does a 20amp emergency stop button exist? in the UK Electrical Forum area at ElectriciansForums.net
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