3 Phase, monitor phase rotation? Optocoupler maybe.

Forums › Home Workshop DIY › 3 Phase, monitor phase rotation? Optocoupler maybe.

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MrJohn

77 posts

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#3025306 21-Jan-2023 21:16

tweake:

i think the guys are being a bit picky. tho i understand the concern with custom made HV gear.

custom HV gear needs tick from sparky as per any HV install and that will depend on the sparky. low voltage such as sensors no such requirements. ie if sparky installs VSD, you can wire any low voltage control circuit to your hearts content.

I am not proposing to make any HV gear but our friend seem convinced that I was inherently unsuitable to plan this job.

MrJohn

77 posts

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#3025308 21-Jan-2023 21:24

Clima:

I have skimmed through this but don't remember any mention of how the mis-alignment is being measured.The purpose of all this is to prevent it going too far so how is it being measured. This surely is the key and will be needed as it is the basis of any solution.

Mis-alignment is indicated by the rail running close to the wheel flange. Close to the flange on the inner side of the wheel indicates this end of the gantry is lagging, running close to the outer flange indicates this end of the gantry is leading. There will be one induction sensor close to the flange on each side of the wheel. Only one wheel needs to be monitored.

When mis-alignment is detected the appropriate motor will be paused.

Clima

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#3025316 21-Jan-2023 23:50

Not sure of the mis-alignment logic. I think it depends on direction of motion and where you mount the induction sensors. May need some precision rails to ensure a consistent spacing. The mounting of the sensors is critical to ensure reliable operation and their protection. They are the key element.

Also wondering why the need to sense the rotation. Presumeably there are Open/Close (or whatever) buttons to control the operation. The state of the buttons , or related state relays, will determine the direction of rotation and can therefore provide directional input to the controller.

MrJohn

77 posts

Master Geek

#3025335 22-Jan-2023 07:58

Clima:

Not sure of the mis-alignment logic. I think it depends on direction of motion and where you mount the induction sensors. May need some precision rails to ensure a consistent spacing. The mounting of the sensors is critical to ensure reliable operation and their protection. They are the key element.

Also wondering why the need to sense the rotation. Presumeably there are Open/Close (or whatever) buttons to control the operation. The state of the buttons , or related state relays, will determine the direction of rotation and can therefore provide directional input to the controller.

Precision rails would be nice but unlikely in these cattle yards.

Sensors will be near the wheel flange and when the rail gets within say 5mm the correction will be initiated by pausing the motor on the end of the gantry that is ahead.

Obviously the selection of which motor to pause requires 'knowledge' of gantry travelling direction and we can get that from knowing the phase sequence at that time.

Yes, there are buttons for start, stop and direction of gantry travel but they are some distance (50 maybe 100 metres) away and in a system designed and built by someone else and best not interfered with unless necessary.

There is an electrical box on the gantry and direction information may be assessable in there but again I would not want to open that for the same reasons as opening the remote control panel.

Volt

43 posts

Geek

#3025355 22-Jan-2023 09:36

I haven't read the entire thread but it sounds like you are talking about a Reporoa Gate or similar rectangular yard backing gate?
These usually are manufactured with their own control system, is there any reason why you want to make your own?

MrJohn

77 posts

Master Geek

#3025356 22-Jan-2023 09:38

It is an existing gantry and gates, 10+ years.

SomeoneSomewhere

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#3025429 22-Jan-2023 11:35

gregmcc:

MrJohn:

Ah yes, which black box gives you concern (assuming you are confident in telling me)? The Arduino, the tracking sensor, the low voltage power supply or the phase sequence detector?

Anything that connects to low voltage in NZ requires a SDoC, will your build come with this mandatory document? - I doubt it, next hurdle will be finding an electrician who would be willing to take responsibility without the SDoC

I think the confusion here is that 'low voltage' means 50-1000VAC/120-1500VDC. Below that is extra-low voltage. The LV>ELV power supply would need to be certified and suitably installed, but that's a pretty easy criteria to meet.

As for 'industrial lego', I would normally consider that to be assembling equipment from commercial, off-the-shelf parts, like the phase sequence relays, PLCs, contactors, power supplies etc listed. Connections made using suitable certified wire/cable, using screw or spring terminals and able to be put together by an electrician that can read a controls wiring diagram (annoyingly few). Parts that operate at LV (not ELV) would need certification.

Even for the ELV gear, I generally wouldn't want custom PCBs, or Arduinos involved, and I'd want proper industrial-grade potted induction sensors, not just a PCB assembly from Adafruit hot-melt glued to a bolt. That's mainly a reliability and professionalism thing.

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Trade NZ and US shares and funds with Sharesies (affiliate link).

MrJohn

77 posts

Master Geek

#3025431 22-Jan-2023 11:59

Thanks for your, and other's, interest in this project from which I have gained a lot but as it stands now I have abandoned this project there being just so much stacked against it.

I must also keep in mind that no matter what I proposed if the inspector on the day did not like the colour of my tie that would be the end of it.

There is a somewhat interesting page here:- https://www.industrialshields.com/programmable-logic-controllers-based-on-arduino-raspberry-pi-and-esp32-20220909-lp

insane

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#3025488 22-Jan-2023 14:41

MrJohn:
Thanks for your, and other's, interest in this project from which I have gained a lot but as it stands now I have abandoned this project there being just so much stacked against it..

My old boss once quoted me this when a particular project faced seemingly endless opposition.

It is not the critic who counts; not the man who points out how the strong man stumbles, or where the doer of deeds could have done them better. The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood; who strives valiantly; who errs, who comes short again and again, because there is no effort without error and shortcoming; but who does actually strive to do the deeds; who knows great enthusiasms, the great devotions; who spends himself in a worthy cause; who at the best knows in the end the triumph of high achievement, and who at the worst, if he fails, at least fails while daring greatly, so that his place shall never be with those cold and timid souls who neither know victory nor defeat. -
Theodore Roosevelt

Unfortunately all too often it's easier to rubbish an idea than to encourage the dooer. I look forward to reading about your next challenge!

MrJohn

77 posts

Master Geek

#3025493 22-Jan-2023 15:07

Thank you Mr Insane!

I seem to have enough on my plate at the moment the main one is a fully functioning replica of a Link Trainer.

https://en.wikipedia.org/wiki/Link_Trainer

This is for our aviation museum here in Ashburton and is all electronic including Arduino! The trainer will operate on MS Flight Simulator..........perhaps I should open a topic on it!

John

mkissin

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#3025551 22-Jan-2023 15:46

insane:Unfortunately all too often it's easier to rubbish an idea than to encourage the dooer. I look forward to reading about your next challenge!

That’s all very wonderful, and I agree with the general sentiment. Shortened down, it would make a good motivational wall poster. However, especially when you’re making something for others to use, you need to consider the failure modes. What happens if someone gets hurt, or you start a fire? I hope your liability insurance is up to date, and you haven’t done anything that would void it like doing something that isn’t allowed under our legislation, or so on.

insane

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#3025608 22-Jan-2023 20:29

mkissin:
insane:Unfortunately all too often it's easier to rubbish an idea than to encourage the dooer. I look forward to reading about your next challenge!

That’s all very wonderful, and I agree with the general sentiment. Shortened down, it would make a good motivational wall poster. However, especially when you’re making something for others to use, you need to consider the failure modes. What happens if someone gets hurt, or you start a fire? I hope your liability insurance is up to date, and you haven’t done anything that would void it like doing something that isn’t allowed under our legislation, or so on.

I didn't say be reckless or flaunt laws, just don't stop because of criticism along the way.

As a nation we need to continue inventing and experimenting - and without people willing to take up that challenge we'll simply be consumers of somebody else's hard work and pay a premium for the privilege.

Some people in this thread, yourself included, gave very constructive advice and provided suggestions on how to proceed. Others simply rubbished the idea and attacked his personal abilities without providing any meaningful help.

I was also genuinely interested to know how this was going to be solved.

MrJohn

77 posts

Master Geek

#3025623 22-Jan-2023 21:57

insane:

I was also genuinely interested to know how this was going to be solved.

All well I think as I have received assistance from someone and I think we have a potential system. It does not have the flexibility of the programable Arduino but with a bit of luck it will be OK for this job.

John

Handle9

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#3025918 23-Jan-2023 20:28

gregmcc:
MrJohn:

Please see EWRB web site and learn if an electrical design is prescribed work.

Your OP did not mention design, it said "What do I need to do to monitor 400v lines and couple to Arduino", not a single mention of the word design

Going down the design track is fine, but your are just as liable to make it "Electrically safe" and judging by what you are proposing I would say no......

He clearly mentions further down that electrical work will be done by the clients electrician.

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