To get the plant temporarily operational as soon as possible , Sulzer quickly completed a partial repair to the failed stator windings . This allowed the cement producer to work through their material stockpile and meet existing orders – which helped to reduce any loss of revenue caused by the generator failure . Illustrating its global engineering flexibility , Sulzer was the only vendor which could offer this partial repair - a testament to the company ’ s customer centricity .
A question of half-bar engineering and manufacturing
Meanwhile , Sulzer worked on redesigning the new stator windings . The 360 ° Roebel bars would eliminate future circulating current problems compared to the original designed parallel conductors . However , this required overcoming numerous engineering challenges due to the short length of the stator core
First of all , fitting the Roebel bars into the short stator core was going to take exceptional technical expertise . The OEM did not offer Roebel bars for this generator model , so Sulzer would be breaking new ground . Precision reverse engineering was required to ensure that the new top and bottom bars with a 360 ° Roebel would fit . Finally , the replacement bars would have to be engineered and manufactured specially for this generator . Thankfully , all these requirements were accomplished
When critical equipment suffers a breakdown , operations and production are always at risk .
in-house by Sulzer ’ s experienced engineering and design team .
A generator upgrade uncoiled
Leveraging its global network , Sulzer Indonesia connected with the Birmingham Service Center in the UK , one of the numerous facilities within Sulzer which has the engineering and manufacturing facilities for high voltage stator coils and half bar production , backed by a comprehensive database and automated design capabilities . This overseas collaboration is common practice at Sulzer , with each facility in its network offering seamless access to the full global capabilities of the company .
Using data collected from the stator and existing top and bottom bars , the Birmingham Service Center reverse engineered the winding to incorporate a 360 ° Roebel . With this complete , engineers precision manufactured a half stator section to confirm the correct fit of winding pitch to expedite installation onsite . Sulzer produced 48 top bars and 48 bottom bars in 10 weeks – a lead time much shorter than the several months quoted by other service providers .
To ensure a continuous workflow and minimize the duration of the winding process , the bottom bars were shipped first , followed by the top bars . This phased delivery allowed the Sulzer Indonesia team to complete the generator rewind sooner , as waiting for a single shipment would ’ ve increased the project timeline by several days . Furthermore , this scheduling ensured that the project could be completed within a planned shutdown period of 10-12 weeks , reducing disturbance to their production operations .
A concrete foundation for reliability
The benefits of switching to Roebel bars were quickly apparent . Winding temperatures were greatly reduced , allowing the generator to be run more efficiently , providing energy cost savings to the cement plant . In terms of reliability , electrical circulating currents were all but eliminated , greatly reducing the risk of any future premature failures . Reduced winding temperatures also meant less thermal stresses on the winding insultation , improving service life . With the generator up and running , the pressure on the customer ’ s other facilities was alleviated too , with the plant now operating at full capacity .
When critical equipment suffers a breakdown , operations and production are always at risk . However , by trusting in the global expertise of Sulzer , this cement producer was able to avoid the worst-case scenario . The customer centric approach of Sulzer prioritized the needs of the cement producer , minimizing any impact to operations or business reputation . Beyond providing a stop-gap repair to keep production running , Sulzer employed its coil manufacturing and reverse engineering skills to build a new foundation for future generator reliability .
For more information , visit www . sulzer . com
Issue 65 PECM 69