Connection diagram required on motor?

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InfernalCombustion

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Background information: I have a 3 phase 480 V motor that was purchased to operate in wye start, delta run configuration. The motor came with a nameplate that only indicates wiring for the delta configuration. There are 12 motor leads in the p-head. I located a proper diagram but this leads to the real question.

The question - While searching the 2008 NEC, especially Article 430 and 430.7 I can find no requirement that calls for a motor label or nameplate to actually include a wiring configuration. Article 430.9 A (Terminals) almost gets there but it seems like a short-cutting manufacturer could just label the terminals T1, T2 etc and meet the "letter" of the code. Does anyone know of a code requirment that requires a labeled wiring configuration for motors (or have I misinterpreted 430.9 A)?

Please forgive me if I have overlooked something obvious. I have worked with the code for years but learn something new weekly.
 
Usually wires on motor leads are labelled with numbers already coming from the manufacturer. All the new motors I ever purchased have stickers or name tags attached to them. I guess, what are asking is that If a motor comes without that information is that a code violation with that installation ? I personally do not know any ?.However, I like to learn if there was.
 
Why should the NEC care if you wire your motor in the right configuration or not? You're free to ruin your equipment if you want to.
 
That is a very interesting question from Marc. In response, my first thought was about the safety of energizing a 20, 50, 300, 500 hp, etc... motor when wired incorrectly. On second thought, If all the protective devices, contactors are sized properly (as per the required info from the nameplate) it should be safe when the breaker or fuses blow. I am not sure that I want to test start equipment that way.


Come on guys, I was hoping for more feedback on this one.

Roger
 
First of all, most motors in the US are not built in the US. I think only Baldor builds their motors here. They have no requirement other than to provide marking of leads and configurations like wye or delta. They are not required to show you how to hook up a wye start delta run. The electrician is responsible for this. And I have found that this type of starting is the most easiest to screw up. 12 lead motors are the present and future in the motor industry as they can used in almost any application.
The NEC does not regulate motors just as they do not regulate manufactured machine panels for industry. The issue with faulty installations can and do cause machinery distruction and possible injury. Lets say you wired a wye start delta run and when it timed out for the delta run it wanted to go in the opposite direction. If it was connected to the equipment I would not want to be anywhere near it. So, you are correct that there is a safety and equipment issue with faulty wiring or faulty mechanical installations.

I have found the use of soft starts and VFD's to virtually eliminate these problems. Today you can buy a soft start for less money than the three contactor arangement required for wye/delta starting. Even on smaller motors you can justify a soft start for price and less wear and tear on equipment.
 
I will agree with John's comment related to the soft start or VSD it is the best way to go espcally small to med sized motorus and far much easier to hook up as well.

I done alot of Y-D hook up and tell ya the truth it kinda pain in the butt with it espcallly with the contractors if you don't do it right it is too easy to get it screw up.

the cost of VSD or soft start will really justify it and a nice bouns along the way you can actally dail in the control to speed up, change the speed.

and the Soft start and VSD is getting more common now and the Y-D is falling out of favour of using it .

Merci, Marc
 
Marc,
Yes, I am seeing more and more soft starts and VFD's. I priced 3 NEMA contactors vs a soft start and the ss was almost half the price. The trick is know who to buy from. If you go with AB and some others the savings are not there. There is a company called Weg Electric and they are based in Brazil. Their main US warehouse is in Atlanta. And they have distributors all around the country. Their prices are so good. Great product too. Automation Direct is another lower cost alternative. They are an internet based company. Check www.wegelectric.com and www.automationdirect.com and take a look at the pricing. With Weg you will see a list price. Use a .50 multiplier and you will get approximately what the actual cost would be. It will be less, but list x .50 will give you an idea. Take a look at their IEC starters to. 1/3 the price of Telemechanique and AB.

ps.....check out Benshaw also. Killer prices and very high quality
 
mdshunk said:
Why should the NEC care if you wire your motor in the right configuration or not? You're free to ruin your equipment if you want to.
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But only if you do it safely.:grin:
 
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