For over 60 years The Anstee & Ware Group have provided electrical and mechanical engineering services to UK industry. From their 7 sites they are well placed to service the needs of industries as diverse as steel, aerospace, oil and gas, utilities, paper and quarrying.
In addition, the company identified an important market opportunity to become leaders in the servicing and repair of traction motors for the expanding rail and mass transit industry. The Company agreed to commit £300,000 to the latest technology to enable rapid and high quality repairs to traction motors, with the focus of the investment to be at their Castle Donnington site adjacent to the famous motor racing circuit.
The company prepared specification documents for open tendering and based on their very long association with Whitelegg Machines and a competitive quote, Whitelegg were asked to supply key pieces of equipment to realise the project.
Anstee specified that certain key pieces of equipment were essential to their new Traction Motor servicing cell which needed to be in place to win major rail contracts for which they were pitching. Key items specified were a surge tester and TIG Welder and Undercutter machines all sourced through Whitelegg, along with a new test panel capable of 0-1200 volts DC.
At Anstee and Ware the normal process for DC Traction Motor servicing-following on from motor receipt at their works-is dismantling cleaning, stoving and inspection with a preliminary bar to bar surge test leading to go or no go. If no go the Armature is completely rewound with new coils. A second surge test is done followed by TIG welding the coils to the commutator risers. The sequence continues with vacuum impregnation, lathe skimming to concentric and dynamic balancing. Another bar to bar test is followed by the undercutting and a final bar to bar test. The whole motor is then run on a test bed at up to 1200V DC. From start to finish a 5 day turnaround is the norm.
Electrical testing obviously plays a major part in this programme with Resistance, HiPot, Surge and Bar-to-Bar tester chosen for it advanced capabilities which were designed to maximise testing accuracy in a lightweight, sturdy format with additional predictive testing capabilities.
Advanced Motor Testing
The Digital winding tester can perform Winding Resistance, HiPot and Surge tests, as well as digitize and store data for future use. Surge testing detects faults in inter-turn, winding and phase-to-phase insulation systems. Using advanced analog-to-digital conversion hardware to captures the surge test waveform, remembers it, displays it indefinitely, and outputs to a printer.
Of particular relevance to Anstee and Ware was the aspect that the lower impedance of series-wound armatures as in traction motors makes accurate surge testing of these coils difficult through normal equipment. When testing these coils a specific voltage is applied on adjacent commutator bars reducing the need for excessively high voltage that could potential damage the coil.
Welding accuracy fast!
Traditional manual welding of new coils to commutator bars can be haphazard, lengthy and inaccurate. The need for high accuracy and rapid TIG welding at this stage of motor servicing was vital. The machine, specified by Whitelegg, can handle core diameters from 100 - 1500 mm and up to an unlikely 999 bars!
Easy to set up, the welder torch automatically moves on to a new weld until the riser is complete. Bar indexing is via stepper motor. Time taken for a standard traction motor has been reduced to four hours
Another traditionally time consuming process was undercutting. Now with the new undercutter in place, the time taken for working a typical Class 66 traction motor has been reduced from 6 hours to 45 minutes! This high accuracy, servo controlled machine is incredibly easy to set up. An important operator aid is a camera with 10x magnification and 15inch LCD screen, enabling easy observation of the cutting area. Laser positioning ensures very high accuracy, unmatched by hand.
The vision of Anstee and Ware and in particular of Keith Hayes, Technical Director in targeting the Traction Motor repair market with new and enhanced test equipment has paid off. The company won contracts for rewinding both Alternators and Traction motors for the Ex BR HST power cars, as well as Class 66 freight locos Traction motor overhauls.
Summing up the programme Keith states, "We knew we had to take the first step in modernising the repair operation at Castle Donington, in advance of tendering for contracts. In the event, the Whitelegg supplied equipment, together with their training and support, helped ensure that my team here were in a position to go ahead with confidence in pitching for the new business. With our new ISO ? 9001 and 14001 certification we are well placed to serve customers for many years to come".