Tuesday, December 28, 2010

Salem Stainless Project 1980, Tamilnadu India

Sorry for delay of this post.. as explained in the last post it was due to non functional Broadband at our place..

During site work at Salem we became friends with many engineers of Salem Steel Plants many of whom were Tamils. Tamil are nice friendly people always eager to help. One of such engineer was Bharatan. He was a mechanical engineer with Salem Steel and was a quite person, he was staying in Salem Town and he will some time travel with us is our Car or Taxi. Any mismatch in coupling finsh boring or any other problem we shall face in execution of 2 Hi mill, he will be there to help. In electrical we had one gentleman called Anil Kumar a Malyali. He was a jolly fellow and we could go along well.

Our Taxi operator was one Mr Goutaman, BA, -- we learned that educational achievements were added as part of name by some people in this part of Tamilnadu. He was nice person giving brand new cars as Taxi. Once her gave us a brand new big car from Ambassador family. This was centre of attraction and it so happened Mr Raju, then Executive Director of Salem plant traveled with is in that car from Plant to Administrative Building. From then onward there was no checking of our car at the security gate for about a month, only then Security personnel realized that it not ED's car.

Oh, I forgot to tell about my Tamil use with Sri DD Sinha during his short trip in absence of Sri CND Nair who went to pilgrimage to Lord Ayappa. We went to see a Hindi Movie as part of daily routine near the railway station. Then Sri Sinha needed to go to urinal. I had learned that "Pungala" means ladies as written in buses in Tamil and I had read it. There was no "Pungala" in front of the toilet and I said Sri DD Sinha to use this toilet. Oh God it was a ladies toilet (though having male urinal fixtures) and there was angry retorts in Tamil both of us could not understand..
Another time we went to a restaurant called Vasanth Vihar in the town a regular place I visited with Mr Vaidyanathan et all. I told Mr DD Sinha, I shall use my half knowledge of Tamil and called the waiter "ainge wa.". Come here. He started reciting the menu. I interrupted  "Tair wada erka?" . Do you have Dahiwada? He told some thing in Tamil - I could figure out .. I have only those I told you before and went away. Sri DD Sinha said now see my sign language. He waved his hand to call the waiter. Then he twisted his hand as if asking. Waiter again recited the menu. Sri DD Sinha said "Masala Dosa" and showed him 2 fingers ie bring 2 masala dosa and Lo our language problem was solved.

I shall tell how we commissioned the AGC cylinder in the next post.

Monday, December 20, 2010

Internet Broadband In India

I promised you that I shall put up next blog on  8th Dec, but my hard luck.. broadband in USA was fast and working, having returned to India, I am struggling with the system of Government Owned BSNL to get my Broadband working... so many task in India you can do over phone.. but when in comes to phones you have to run, go, worship and many other things to get your phone going despite paying the excess billed amounts... God how we can achieve the growth in Steel or other sectors of economy? Forgive me my next blog is going to be delayed further...

Friday, December 3, 2010

2 Hi Skin Pass Mill at Salem Steel Plant, SAIL, India (1980)

Pulpit of  5 Stand Tandem Cold Mill at Bokaro Steel Plant - India (Ordered on MECON in 1977)

Stainless Steel Plant at Salem :

Though I have included a picture of 5 Stand TCM at Bokaro as part of 4 MT expansion of the SAIL plant, as promised in my yesterday's blog here I am with story related to Salem Plant of SAIL.

Location and configuration of Salem Plant was more affected by political consideration than technical or commercial. Here I have no intention of offending any body or any region, and I apologize in advance if I hurt any body's feelings due to this observation. Salem plant engineers always showed us a near by hill by the name of Kanjmalai supposedly rich in Iron Ore as a reason for the plant location, however till now no mining from this hill have been attempted. In fact the plant was originally established as rolling mill complex having cold mills and lines leading to such observations. The plant was initially getting hot coils rolled in other units from raw materials produced in Alloy Steel Plant near Durgapur in West Bengal India. These distances defied normal logistics costs and initially gave an impression that the plant shall not be commercially profitable. The plant was more like a large re-rolling mills and lines. However following positive things happened :
1) SAIL established first plant for Stainless Steel.
2) Salem Stainless Steel set new quality standards for Stainless Steel in India.

Now about my experience as part of MECON team involved in 2 Hi Skin Pass Mill's execution. MECON designed, manufactured / procured and erected and commissioned the Skin Pass Mill. Wean United Inc, Pittsburgh, USA was MECON's technical collaborator and BHEL/ Siemens Ag delivered the electrics. I was looking after electrical equipments from MECON side and was responsible for preparation of motor list and functional write up and commissioning of the plant as per the functional description. I have 3 stories to tell about our experience at Salem. 1) Experience regarding initial commissioning and inauguration of the plant.2) Experience during Performance Guarantee test 3) Experience of recommissioning of CO2 fire fighting system supplied by MECON.

I am going to write about the first part today and other 2 experiences will follow in subsequent blogs.

M/s Puegot Louire of France was process consultant while MN Dastur was engineering consultant for the plant.There we myself, Mr Nair from Hydraulics Department and Mr TV Vaidyanathan from Manufacturing and Construction department were posted from MECON. We had a nicest coherent team of MECON without inter disciplinary fight .. not even once..
Some none technical things.. this may be interesting ..
I was not originally assigned this job, how ever my current boss that time Mr BP Goyal (Now Director at Jindal Stainless and briefly my boss once again at Jindal Stainless where I worked as VP-Projects in CRM), was not happy with me for some reasons and put me under Mr SM Ganguly (Presently with SMS-India) who was showing concern of not having any body to help me.. result I was posted to faraway Salem. Despite a family tragedy - I lost my father in an accident - I went to Salem and this lasted for about 10 months initially. We used to stay at a Hotel Called 'Gokulam' near Five Road Junction in Salem. Nice Hotel. Film Stars like legendary Silk Smitha and cricketer like Kapildev stayed in the hotel while we were there. One waiter by the name 'Manjunath' took good care of us and we never got hungry even if very late in returning from Site. He kept some thing to eat in our rooms. we referred to him as 'Manju' in our conversations back home to tease our wives..
Our routine was work from 8AM to 1030 PM and late night movie mostly Tamil or Malyalam almost every day. There were almost 60 cinema halls in Salem and around. In case there were any Hindi or English movie running, I could not know where since name of the cinema hall will be in Tamil. I learned to read Tamil to overcome this problem and I can still read hoardings and headlines in Tamil.... Two friends of mine used to help understand the dialogues and I used to be last to laugh on any joke. What disaster my little knowledge of Tamil did during visit of Sri DD Sinha (rose to become GM- in MECON) to Salem in my next post..

I will continue this topic tomorrow or may be on 8th Dec onwards since I am traveling back to India from US.

Wednesday, December 1, 2010

AGC sensors and Controls- changes in 1970-80

2 Hi 1500 wide, Skin Pass Mill, Salem Steel Plant, India by MECON Ltd with Hydraulic Force cylinders (1980)

I like to share few personal AGC experiences encountered during 38 years in the field of rolling mill automation and controls. First one being Hot Strip Mills of Bokaro   in India commissioned in 1975. I was one of the electrical commissioning engineer mainly involved with 132 /11 kV main step down substations and 11 kV supply system and motors. 11 kV synchronous motors of up to 110 MW was commissioned by me and my friends for Roughing Mill area. These stands were not with any AGC system, however 7 stand finishing mills were equipped with electro mechanical AGC system commissioned later on .. till then mill was running on manual thickness controls.The AGC system used DC screw down motors fed from circulating current type thyristor converters (SCR) and main motors were DC motors fed from Mercury Arc rectifiers fed from Zig Zag connected double star transformers.

Actual AGC control has been achieved through the use of Russian operational amplifier system called UBSR. This system allowed changes in amplification and time constants by changing capacitance and resistances using normal soldering of these passive devices. These changes were done based on time constants of mechanical systems or electrical motor circuits and we tried to achieve a step response within minimum possible time and allowed up to 4% overshoot in the first crest so that the feedback system is optimally damped. Sensors used were Selsyn transmitters, analogue tachos (they looked like DC motors those days) and X-Ray Thickness gauges. Inter stand minimum tension controls were achieved through the use of  stall motor controlled loopers.

I can recall 1 incident which took place those days - Hot Strip Mill was commissioned during the time Emergency was declared in India. We had kept transformer no 2 of 132/11 kV main step down sub station no 2 ready for commissioning except for break down value of bushing oil which was less than 40 kV in the Russian pot we used to test the oil. While our commissioning department preferred internal heating by feeding the transformers at 11 kV and shorting of secondary terminals (calculation for short circuit current was made for these transformers having over 20% impedance), erection department went ahead with heating of bushings with flood lights covering then with Tarpaulins. One day while we returned after lunch at 1:60 PM (that's how we shall joke about being in time at 2.00 PM),due to  lightening the Tarpaulin caught fire and the bushing cracked under heavy rains. Those days we use to develop affection with the equipments and I was in tears. Flame from the fire started reaching 132 lines of Transformer no 1 which was charged. Our efforts to convince the operator at MSDS 1 to switch off 132 kV power to this transformer was going in vain since he wanted permission from Sri BB Dutta, Chief Power Engineer and a difficult person. Then I remembers the differential relay for 132 kV air blast circuit breaker of MSDS1 located in our substation (commissioned by me earlier). I manually actuated that relay and saved major accident since the 132 kV line was about to snap due to the heat of the flame... In subsequent days my boss Mr JB Prasad got lot of praise for this action of mine...

Tomorrow I shall write about experience we had in Salem Steel Plant in India. I have included a photo of 2 Hi mill by MECON in that plant...in this post itself.

Tuesday, November 30, 2010

Cold Rolling Mills AGC improvements in 80's

Gauge control through Mechanical Screw Downs :

Prior to late 70's AGC for a Cold Mills were with Mechanical AGC system with DC motors driving screws in each housing posts and controlled earlier as feeler control manually and later automatically via a unigauage controls and feed back through X-Ray Gauges - reversing mills were having 2 thickness gauges. Roll force measurement via a washer type load cells (may be from Kelk or ABB were used to measure stiffness of housing posts and position of screws were measured via selsyn in earlier systems and pulse tachos in more modern system. This system gave tolerances may be of 5- 10 microns on the strip due to slower control of DC motors of screw downs. More closer controls of thinner strips were obtained using tension controls of Reel drives which were incidentally faster than mechanical screw downs.

Hydraulic Cylinders used for Gauge Controls:
Dramatic change took place in late seventies when Hydraulic AGC Cylinders - earlier short stroke ones and later larger stroke cylinders  were employed for the purpose of AGC controls and improved the time constant from say 200 mS to 20 mS and paving a way for accuracies in the range of 1-5 micro metres. There were some changes in the instruments used for AGC also such as use of 4 nos Position Transducers such as Kelk make Absolute Position Transducers or Sony Magnascales (later only 2 nos Position transducers placed centrally in the cylinders were used)and pressure transducers for load measurements.

In Tandem cold mills last stand was usually used as tempering pass and Siemens defined A, B, C mode of controls for Tandem Mill stands.

BBC which later became ABB also introduced various modes of AGC before it was developed as it stands today. These changes were needed due to technological improvements and due to the fact Hydraulic AGC were getting introduced as modernization of old rolling mills. Space constraints in existing Mill housing windows compelled use of short stroke cylinders along with mechanical screw downs for coarse correction earlier. In India one of the first introduction of Hyd AGC was in Rourkela's existing  Hot Strip Mill by MECON and Wean United with BHEL / Siemens Ag being electrical partner the modernization was   completed in record 40 days shut down saving 5 working days for the plant production against projected schedule.

I shall be putting other improvements in these aspects in future blogs..