Legalities of incorrect polarity upon purchase.

[wade88]

Hi guys,

Now, on two occasions now, a supplier of some of our machinery have supplied machines with incorrect polarity within the plug tails.... on today's instance, this obviously ran the motor in reverse, and has caused irreversible damage to the machine in question. I have now correctly wired the plug and double checked the internal terminations. The machinery they supply is built in China, its rough round the edges to say the least, and as far as i am aware, China do not follow any standardisation when it comes to wiring things, they just sling any old cable and colour in there.

But i find it utterly unacceptable that a machine supplier who fabricates and alters these machines to suit the clients end result needs, is sufficiently incompetent enough to wire the plug wrong and then deliver it "fit for key turn use" to a customer.

Today cost me time, blood and money after the machine almost fell to bits running in reverse, and i was wondering if there are any legal ramifications of sending machines out their dooor bought and paid for, that are in my opinion, potentially not safe.

Ben

 

[piccollo]

Dear Ben, had similar, I believe there is a general practice L1L2L3 N, but how many times do you find the wrong phase rotation on a incoming supply.
Just because the cores are correcetly connected, did they check for phase rotation. We know how to correct it, but as you say if the equipment is not marked or was tested else where, we don't find out until we try. piccollo

 

[44ALLAN]

My career average is 50% on going the wrong way when energising a 3phase motor for the 1st time
Quick on and off to check rotation before running it is the best way.
Good little tip for checking direction as well is to stick a tywrap into the cooling fan if you can't see it properly for rotation.........makes a great noise too just like the gizmo I used to put on the spokes of me bike when I was younger lol

 

[wade88]

Haha, thats brilliant, or get a piece of paper and see if it sucks it or blows it.... no innuendo intended.

Ok, well i wrote a pretty unimpressed email to them anyway, suggesting they get someone in who knows how to wire a plug before selling machinery to people, I just find it gobsmacking that their company "electricians" who are responsible for electrical integrity of their machinery before its sold or whilst its being built to begin with, are sufficiently ill equipped mentally to carry out the most basic electrical fitting job there is to the machine.

Cost me time and money today to sort that out after the domino effect of trouble it brought.

50/50 is a truly shocking percentage of incompetency or laziness.

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or am i just making too bigger deal out of this

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should i fetch my tiny violin

 

[44ALLAN]

Haha, thats brilliant, or get a piece of paper and see if it sucks it or blows it.... no innuendo intended.

Ok, well i wrote a pretty unimpressed email to them anyway, suggesting they get someone in who knows how to wire a plug before selling machinery to people, I just find it gobsmacking that their company "electricians" who are responsible for electrical integrity of their machinery before its sold or whilst its being built to begin with, are sufficiently ill equipped mentally to carry out the most basic electrical fitting job there is to the machine.

Cost me time and money today to sort that out after the domino effect of trouble it brought.

50/50 is a truly shocking percentage of incompetency or laziness.

- - - Updated - - -

or am i just making too bigger deal out of this

- - - Updated - - -

should i fetch my tiny violin

Look at it this way mate.......you could take your motor to 100 factories anywhere in the uk and plug it in to several different points in those factories and 50/50 would be a good result
Phase rotation and wiring in plugs/sockets/d/b's etc are all different.
Trick is to realise that and take all loads off a motor before powering it up for the first time........then quick on/off checking for rotation..........never run a machine full hog thinking it's automatically going to go the correct way..........won't happen believe me

ps
My record is actually 70/30...................................getting 30% right isn't too bad I thought lol

 

[wade88]

Ok, point noted, couldnt run this kit half ars ed anyway its on or off but it just wrapped itself around itself going backwards. However, today i learnt that more often than not expect the work of a numpty, take nothing for granted...not even correctly wired plugs. *sigh*

 

[gazzamikes]

Brave man starting it up! Sorry for asking but in what way could the motor not be disengaged from the drive train of the system?

 

[44ALLAN]

Ok, point noted, couldnt run this kit half ars ed anyway its on or off but it just wrapped itself around itself going backwards. However, today i learnt that more often than not expect the work of a numpty, take nothing for granted...not even correctly wired plugs. *sigh*

What happens Wade is that when someone finds a motor going the wrong way they may go to the isolator or D/B and change the connections in there on the main cables........this knocks everything out of sync and if this happens every time and all around the factory/site then it's anyone's guess which way it's going to turn regardless of how the plugs wired up.
Change the connections in the motor terminal box or the load side of the contactor then your main wiring is left alone........won't ever happen but it's a nice thought

Sorry if that post sounds patronising mate just read it back to myself.
Get work to buy you a phase rotation indicator for the next time

 

[wade88]

Oh well this piece of kit in particular was delivered with the incorrect wiring. DB's are all fine as did them myself (obviously they are ok..... :\ ) haha

It is run from an automatic run sequence that is written into the machine it is feeding's run program, so it plugs into the machine direct, then runs when the level sensor detects free space. So when it was plugged in and machine was energised, it just went straight into reverse before i had a chance to even scratch my ar s e.

No biggy now though, I am a wiser man for the tips.

 

[wade88]

Brave man starting it up! Sorry for asking but in what way could the motor not be disengaged from the drive train of the system?

Oh it could have been had i decided to check for correct polarity first and disengaged the motor prior to starting it up. Simply case of more haste less speed mate. Everyone on my back 24/7 here to have things working and machine down time to 0.1%, so i was clearly a little hasty turning it on, and also didnt expect the plug to have been wired backwards in the place.

Everyday is a school day