Electricity and Control January 2020

DRIVES, MOTORS + SWITCHGEAR : PRODUCT NEWS

Overhaul and repair on drilling rig motors LH Marthinusen (LHM), a division of ACTOM and manufacturer of specialised transformers as well as a leading repairer of transformers and large rotating machines, recently completed a general overhaul on seventeen ac variable speed induction motors in operation on a drilling rig. The vessel where the drilling motors were in operation was on a ‘class renewal’ stopover in an international harbour. Due to an upcoming drilling contract, the class renewal period was reduced from the normal 14 weeks to nine weeks. This necessitated a fast-track overhaul of the drilling rig duty motors so the process was performed in sequence. The motors were palletised, shrink-wrapped and containerised for the return shipment to the port where the vessel was docked. All the motors were overhauled and returned within a five-week period. The process included the full assessment of the condition of the motors and reports were submitted to the client for each unit. Each unit was disassembled, cleaned, andmechanically and electrically assessed. The rotors were then balanced and bearings replaced. In order to meet the strict timelines the specialised bearings had to be purchased beforehand as they were long-lead import items. Replacement components were issued with Certificates of Material Conformity, as required for the class renewal overhaul. As a result of this being a high duty application, there had been excessive wear on the shaft journals. The shaft journals were rebuilt and brought back into specification. And, because it is a marine application, the stator windings

ATEX approval for combi switchbox The GEMÜ 4242 combi switchbox is designed for varied industrial working environments and all common process landscapes. It also meets special requirements for application in classified explosion protection areas such as ATEX, IECEx and NEC, and has the corresponding approvals. In addition, the GEMÜ 4242 combi switchbox covers varied electrical connection scenarios. These include communication via IO-Link as well as integration in modern fieldbus systems such as AS-Interface or DeviceNet. Backward compatibility is guaranteed, and the integration option with various AS-Interface profiles also enables retrofitting of older plants. The GEMÜ 4242 combi switchbox is systematically designed for user friendliness. Microprocessor controlled functions and intelligent and user-friendly program routines facilitate commissioning and service of the valves. With the ATEX approval on its 4242 combi switchbox, GEMÜ is expanding its range for use in explosive areas in diverse industrial environments and processes. were treated for moisture suppression. The international client also accepted LH Marthinusen’s marine paint specification as superior to its own internal standard. In terms of the contractual requirement, the client’s mechanical OEM witnessed the fitment of the shaft hubs, to ensure the OEM equipment standards were met. As the units operate in a potentially explosive environment, the assembled motors were inspected by an appropriate standards authority and the Ex Certifications of Compliance were issued. Prior to dispatch, the motors were no-load tested at full voltage and 60 Hz operation. The client was satisfied with the workmanship and a further four units were sent to LH Marthinusen for inspection and overhaul. For more information contact LH Marthinusen: www.lhm.co.za

For more information visit www.gemu-group.com

The GEMÜ 4242 combi switchbox is designed for diverse industrial environments including explosion protection areas.