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15 comments
Commentator

Join Date: Jan 2013
Posts: 70

The Unexpected III -Motors in a Fertilizer Plant

05/09/2013 3:42 PM

The scenery a fertilizer plant builded on 1969

A fertilizer plant integrated by an ammonia plant, Nitric Acid plant, Ammonium Nitrate plant, Urea plant and associated services like boiler, sea water cooling etc.

The thing was that at the moment to start the 250 HP 6 Kv motors( five in total) in succession all of them burned out at the moment to press the start push button.

The motors from manufacturer (x for ethic) supposed were running for 4 hours as part of manufacture test as well as all other work practice and reported ok in their test certificate. the on-site test like winding insulation, polarization index and absorption coefficient read ok.

Then what was wrong in this issue ? ?

It is not a test for your but really result interesting to know. I can forward that the problem was technical and commercial trick that could happen to anyone

Bye

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Guru
Engineering Fields - Power Engineering - New Member

Join Date: May 2007
Location: NYC metropolitan area.
Posts: 1440
Good Answers: 190
#1

Re: The Unexpected III

05/09/2013 4:55 PM

6 kV phase to phase or line to ground, delta or wye internally, improper phase order?

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Commentator

Join Date: Jan 2013
Posts: 70
#8
In reply to #1

Re: The Unexpected III

05/10/2013 1:23 PM

Thanks all of your for your comment well focused but next what really happened

The commercial ruse was as following:

The motor manufacturer change the stator slot design from strainght shape into slope shape to all motors from 250 HP and above.

The problem arose at first start moment, at both end of winding coils due to a high stress developed whend the coils are forced against to slope slot laminated edge, therefore damaging the coil insulation and hence the winding fault to ground. (IT WAS THE TECNICAL MISTAKE).

there were more than 60 motors in the same situation of wrong design.

What the manufacture did ?: Just sold the failured motors to ovesea supposed purchasers with long time scheduled to motors install and meanwhile get enough time to money recovering due to the loss.

They knew that Urea plant is always scheduled for last statrting in fertilizer complex. (IT WAS THE COMMECIAL RUSE).

N.B. this bad design was ignored in the handed motors test certificate which also must stated that motor shoud run about 4 hour as part of test proceeding

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Power-User

Join Date: May 2009
Location: From the heaven.....
Posts: 190
#9
In reply to #8

Re: The Unexpected III

05/11/2013 4:36 AM

I am unable to understand the OP's English ..........I doubt my abilities of understanding the english.......confused...not able to understnad the head & tail...

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Guru
Technical Fields - Technical Writing - New Member Engineering Fields - Piping Design Engineering - New Member

Join Date: May 2009
Location: Ketchikan, AK, USA
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#10
In reply to #8

Re: The Unexpected III

05/12/2013 9:50 PM

Good riddance. Thanks a heap for the fun and games.

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Guru

Join Date: Jun 2006
Location: Ottawa Canada
Posts: 1846
Good Answers: 113
#11
In reply to #8

Re: The Unexpected III

05/13/2013 9:49 AM

What is the problem, I understood what happened! The OP has found that a batch of motors he was sent were improperly manufactured, and the supplier knew it, Yet delivered them to a customer and took the money for the bad product. The supplier knew that they would have to honour their warranty eventually, but the long lead time allowed enough sales to cover the losses over several sales quarters.

Because I cannot imagine a manufacturer actually admitting this, it might be all speculation on the OP's part, but it makes perfect sense. Personally I would never order from that supplier ever again, but who knows who will win the next bidding process. Losses incurred from the delayed start would not be assumed by the manufacturer, but by the engineering firm who signed the testing certificate. One or two engineers thrown to the wolves, and the manufacturing plant is saved.

What exciting drama! Beats the heck out of what we see on TV these days!

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Commentator

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#12
In reply to #11

Re: The Unexpected III

05/13/2013 2:22 PM

Yes, Mr Yusef1 difficult to understand but it was absolutely true, the manufacturer make trick to recovering their invesment in motos bad design (mufacturer no mentioned for ethic reasons) the actually in fact is that the five motors burn out during the first start during precommissionig stage despite declared test cetificate said that the motors were running during four hour at work.

And for other that not undestand my english the failure reason was due to change on the stator slot from strainght shape into sloping configuration as I explained in my first post.

This was part of mutual confessions between buyer and seller at the end of the work whith the plant already at full production where not claim took place.

The five motors were replace in time for start-up the Urea plant so no reasons for any claim.

It's not a lesson but a good experince for some forum members

Bye

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Guru

Join Date: Jun 2006
Location: Ottawa Canada
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#13
In reply to #12

Re: The Unexpected III

05/13/2013 4:28 PM

In time for start up! Yay!

I can see an entire engineering firm breathing a great sigh of relief! But I would still fire the signators.... or give them golden parachutes for being team players. Its the way the game is played, I guess. I don't have to like it, and I don't.

Glad your plant got up and running in time Juan, and I hope some management weenie did not blame you!

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Guru

Join Date: Dec 2007
Location: Mumbai, India
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#14
In reply to #12

Re: The Unexpected III

05/14/2013 7:14 AM

Juan, I will talk in simple English so that you can understand easily.

It is not question of your mutual settlement with motor supplier. It is some thing called Cheating which should never be tolerated no matter where ever you are located.

May be in your country you can forgive supplier for such cheating case but not in the other countries.

I think your company made big mistake in purchasing such high horse power motors from small company which did not have design experience for such motors.

You may clarify the situation in your bad English no problem we would try to understand.

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Commentator

Join Date: Jan 2013
Posts: 70
#15
In reply to #14

Re: The Unexpected III

05/14/2013 2:21 PM

Thank Mr Suresh: You are right this kind of cheating can't be tolerated by anyone but there are some point to be clarify in this issue:

  • There was not mutuaul settlement between the motor supplier and my company becouse it was a contract with an EPC which were also deceived
  • The motors manufacterer is still a famous firm, not small, I did not named by ethics
  • We are small island and with poor experience at that time (1968)
  • The EPC paid for that and other mistake a lot more for bad design (5 million of USD in international court)

Like I express before, the motor supplier deceived the EPC and sold the bad design motors just to recover back the money placing the motors in the right market to get enough time. a classic dirty business

that is the history

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Guru

Join Date: Apr 2011
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#2

Re: The Unexpected III

05/09/2013 7:35 PM

Corrosion of the wiring/windings of the motor related to the nitrates/ammonia/urea ?

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Guru

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Location: Ottawa Canada
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#3

Re: The Unexpected III

05/09/2013 8:58 PM

The load was too heavy.

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Active Contributor

Join Date: Jan 2013
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#4

Re: The Unexpected III

05/10/2013 1:54 AM

Just a shot in the dark, but it sounds like you had a dead phase leg. Or the motors were wired for a lower voltage for testing, and someone forgot to rewire them for the higher 6 Kv operation.
Most 3 phase motors will start with only 2 legs active, but will burn out very quickly.
Is there a VFD or soft starter on these motors? if so I would also check the programming on those.

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Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

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#5

Re: The Unexpected III

05/10/2013 3:06 AM
  • Water ingress?
  • Dirt ingress?
  • Output shaft jammed and overload protection devices incorrectly set?

Is there a prize for the correct answer?

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Power-User

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#6

Re: The Unexpected III

05/10/2013 7:49 AM

You have a common mode failure - something that has hit all of the drives. Its unlikely anything was jammed or full of water because the same thing would have had to have affected all. A common mode would be as one subscriber has mentioned a phase leg down.

Have you run the drives since a shutdown. Are they wired suitable for the voltage.

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Guru

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#7

Re: The Unexpected III

05/10/2013 7:54 AM

It will be better if you let us know the name plate data or Test Certificate details so that we can give you detailed comments. For motors to work in chemical plants windings need special treatment against chemical corrosion. What sort of protections were provided?.

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Users who posted comments:

giri (1); Horizon3 (1); juan J. Isdray (3); PWSlack (1); RAMConsult (1); silverfox (1); suresh sharma (2); Tornado (1); truth is not a compromise (1); Yusef1 (3)

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