Friday, January 14, 2011

2 Hi Stainless Mill at Salem, By MECON, Edge Guiding System etc.

Hope you may have read my earlier posts, I am awaiting more and more comments. This post is regarding edge guiding system by GPE provided by MECON with electrical controls- meaning there by BHEL's scope was limited to one feeder in MCC.

As told in earlier blogs, BHEL was main electrical supplier and their 4-5 engineers were posted at Site for commissioning. I was a guiding engineer from MECON, since MECON was involved on overall design and we knew complete project from incoming power supply to end connections. From Panel and transformer locations to cable route to main and aux motors and motor and ECR ventilation. BHEL had experts of converters and power systems. While I had taken over MCC commissioning including building of logics as per our functional descriptions, when it came to Edge Guiding system controls, BHEL threw tantrums that this is not in their scope and they will not commission it. I though of commissioning it my self. I had 7 year of  hands on commissioning experience while at Bokaro Steel (SAIL) and had commissioned large units alone such as 5 units in Sinter Plant-1 (Screening unit, Crusher plant, coal storage and handling, large Synch Motors, mid section of Sinter Bed-1), MSDS2& 5, Roughing section of HSM - 5x 10 MW motors, Pickling Line, CRCF etc & this was a small thing to do. I was however little apprehensive regarding support from Head Office, since such direct commissioning work was not attempted by MECON earlier. I found electronics for GPE was simple using photo sensors to detect edge and generate a positive or negative reference depending upon whether photo cell was covered by strip or not. This will move the POR to or away of the mill till the light was just half covered. Simple. Only adjustment was sensitivity and speed of movement for a given error. I had already commissioned manual part of cylinder movement and GPE controls only needed to be activated using blocking valves of main hydraulic circuit. This commissioning enhanced my image with Salem Steel operation personnel who started approaching me for any modification they needed for equipment controls. I also obliged by modifying circuits for problems like creeping of walking beam's long travel cylinder.

Later due to use of contamination prone aux Hydraulic system B for GPE, the servo valve started malfunctioning and myself was sent along with Mr Narshihman of Lube section of MECON to rectify. Similarly CO2 fire fighting system from M/s Vijay Fire also was not functioning. The system was a turnkey supply by M/s Vijay Fire and several visits by them did not resolve the problem fully. 

Mr Narsihman was totally at loss to understand the edge guiding system's hydraulic circuit. He was not sure why a blocking valve was provided and why there were "left" and "right" movement valves in addition to GPE valves. How he opened the servo valve despite warnings in GPE's literature and thus spoiled the servo  action and how Sri TR Rao tried to salvage the situation in our next visit to Salem will be detailed out in the next blog on the issue. Please read on as to how we had spent all money we had during PG test and we were about to miss our flight back to Calcultta (that is how it was pronounced then) due to a problem in Madras or Sennai (as written at the airport in Tamil even when not officially renamed.

1 comment:

  1. I have received following comments from Sri Kalyan Bhattachatjee which I am pasting verbatim
    I could not insert a comment in your blog. It requires some profile etc. But here are my commemnts:You can insert those.
    You forgot 2 non-technical episode.

    1. Invitation of Mr Rana to Mr Sarkar for a movie (Inside a taxi).
    2. Effects and after-effects on commissioning due to presense of "Silk Smitha" in the same hotel for a Tamil movie shoot!

    Best reminiscence.