Dear all

Greetings from Sanjoy Roy Chowdhury of Abul Khair Steel Melting Ltd., Bangladesh, the biggest steel manufacturer of the country.I am working as an Assistant General Manager in the electrical department of our rebar mill.

Actually we are facing one critical problem in our collection area rectifier unit.The thyristors  of Rectifier are getting damaged. After replacing the faulty thyristor the rectifier is working. But the problem is recurred within a week. We have done following jobs

• We have properly check the all of the  related parameter like motor , input /output cable, auto transformer , line inductor, power supply . But not found any abnormality.
• We have replace new rectifier unit but the rectifier also got damaged
• Collection area have two section one is “A “another one is “B”. The rectifiers is common both of the section. If the rectifier fails both sections do not work. As a result production stopped.So, we have installed rectifiers for both sections separately to continue production. The rectifier of  A section was damaged at midnight today. Now collection area is running  with B section
• We reduce the value of Regen Curr Limit (P161) from -90% to -60% for both rectifier.

Right now we don’t have any spare rectifier. If any problem might happen production will stop any times . Therefore, we seek your technical support so that we can resolve the issue permanently .For you reference I have attached the single line diagram of collection area rectifier unit .

The rectifier model no of collection area is  6SE7036-1EE85-1AA0-Z. Can you please check whether the said model is available in your end? If so please send the commercial for that . Or you have any alternative solution/suggestion  to replace another model?

Awaiting for your kind reply.

Regards

Sanjoy Roy Chowdhury

Assistant General Manager

Abul Khair Steel Melting Limited

[snip]

ok sir next time i will take care about my post.