18 maintenance
Adapting to keep industry moving COVID-19 is forcing industries to think and react differently. From maintenance technology to witness testing of key assets, things are already starting to look very different. ABB’s David Hughes reflects on some of the changes that have happened since the pandemic restricted our normal ways of working.
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ndustries are saturated with pumps, fans and compressors – many of which are driven by large synchronous motors and generators. Today many of these assets are being asked to perform at unprecedented levels, with some being re-defined as critical assets used for pumping large volumes of water or compressing high volumes of oxygen. With many of these assets installed in the 1990s and earlier, their reliability is without question. However, such is the criticality of their applications today that greater focus is being placed on ensuring a robust maintenance policy, so that these machines never fail. The recommended maintenance program for ABB’s synchronous motors and generators, for example, consists of four levels, L1 - L4, each of which takes place throughout the life of a machine. For the classic motor/ generator installed around the 1990s, the most intense maintenance is L4 which is usually carried out after 80,000 hours or 12 years of operation. It is often at this stage where digital technologies are coming to the fore. ROBOTIC AIR-GAP CRAWLERS Recently, ABB’s UK service engineers were asked to carry out a planned preventive maintenance inspection of a critical compressor, driven by a large synchronous motor. The team deployed the air-gap inspector – a miniature, video robot that crawls in the air gap between the stator and rotor of large synchronous motors and generators. The robot traverses the stator core laminations using modular, magnetic tracks. The inspection revealed that the rotor winding’s V-block support mechanism had lost its pre-tension. This required the rotor removal and replacement of critical components. While the robotic crawler had clearly saved the day by identifying an imminent failure, the age of the motor and its critical application was about to test the flexibility and ingenuity of ABB’s engineers. Planning and manufacturing the required materials for a synchronous motor of this vintage can typically take ten weeks. However, such was the urgency to put the process back into production that ABB managed to fast track manufacture and supply of the materials within one week. The feat is even more remarkable as the motor’s age meant that, while most components were in stock, the more critical rotor insulation plates needed to be purposely cut. The challenge was further compounded by the fact that these project-specific insulating plates were not fully or accurately set up in the SAP ordering software, thereby missing critical drawing references. Experience of the engineers involved ensured that they rapidly determined the insulating plate data. With the correct information now entered in SAP, the motor factory’s production planning ensured that the right plates were cut in advance, thereby avoiding losing valuable time.
Quarter 2 2020
ABB Air Gap Inspector
ONLINE FACTORY ACCEPTANCE TESTING Meanwhile, other customers were facing a different dilemma. With the motors and generators they have ordered now built, it is normal for customers to visit the manufacturer’s facility to carry out an intensive factory acceptance test (FAT). The social distancing rules of many countries, however, made such an event impossible. To help overcome this, ABB’s factories in Finland, China and Estonia are now embracing the world of live video feeds to let their customers witness test machines before delivery. A camera system provides a live video feed of the FAT, giving a complete overview of the testing floor arrangement and the machine’s running status. Intermediate results from the testing software are shown on the video feed, including temperature graphs, voltage and current. The online FAT application works within web browsers without any special IT requirements. To take part, the customer needs an internet connection and a link to the FAT web browser application. The necessary login address, username and password are sent by email, enabling customers to watch the FAT on either a computer or mobile device. This avoids the need to travel to the manufacturing sites, as the online FAT can be viewed remotely from virtually anywhere in the world. By eliminating travelling time and associated costs, online FAT offers extra flexibility in customer schedules. Following successful completion of testing, final inspection of the completed machines is achieved by means of a client agreed checklist. Inspection photographs are also issued as evidence of quality so that customer release documents can be issued. www.bpma.org.uk
