65 Motor development and manufacturing | Focus E-Mobility Engineering | July/August 2024 Capturing requirements While there is no substitute for talking with customers, much worthwhile progress can be made in requirements capture, with well-designed templates for prospective customers to use, often presented in web form. One motor developer we consulted gathers details on the installation space, electrical supply and cooling concept at an early stage of development in this way. This enables them to record and understand the existing system architecture as much as possible to fulfil requirements with customised designs. “We use a design sheet with a rough calculation to make the designs plausible, taking electromagnetic, thermodynamic and fluid dynamic aspects into account,” an expert says. “The design sheets form the basis for the technology modules, the topology of the motor and the winding schemes, which are later detailed together with the customer, from which a design for manufacture is derived.” Another motor developer says some customers provide detailed specifications in multi-page documents, while others make use of its web forms. For example, on the company’s custom motor-design page, when a prospective customer clicks on ‘performance requirements’ they are invited to enter data on the machine type, DC bus voltage, maximum torque, continuous torque and stall torque, maximum speed, continuous speed, maximum and continuous output power figures, and the maximums for drive frequency and current. A third developer stresses the importance of harmonising requirements from multiple market sectors and of conducting early-stage concept analysis to evaluate systems integration, according to its expert. The engineering team also conducts frequent voice-of-customer (VoC) meetings to hone their understanding of the requirements. “We capture both the industry regulations and VoC feedback in one of the industry leading requirements managements tools. In forming concepts, we focus on simulation-driven design and rapid prototyping to shorten development,” the expert says. “We work closely with our customers (who can be motor suppliers or endusers/OEMs) to understand their motor performance and design requirements during early development,” says an expert from a producer of speciality, soft magnetic alloys, and of stator and rotor stacks from iron-cobalt alloys. together, represent large investments. These include the machines that wind copper or aluminium wire onto rotor and stator cores, and those that bend hairpin conductors and others that insert them into core slots. Core manufacturing requires laser cutting or stamping equipment to shape the electrical steel laminations, and equipment to assemble them into the stacks that form the rotor and stator cores. Accurate alignment of the laminations is essential for motor performance. Manufacture also entails machining multiple different components, such as shafts, housings and end-brackets using processes such as milling, drilling, tapping and boring. Increasingly, these processes are carried out with multi-tool machining centres – CNC systems capable of producing parts with complex geometries. Insulation and coating equipment apply protective coatings to components such as the stator windings and rotor shafts to provide electrical insulation and thermal resistance, for example, and to enhance durability. For motors produced in small numbers, manual assembly is often practical, but scaling up requires automated assembly lines with stations for tasks such as inserting coils into stator slots, joining stator and rotor assemblies, installing bearings and sealing motor housings. At practically every stage of production in a modern factory, material-handling systems such as conveyors, robotic arms and automated guided vehicles (AGVs) move parts between manufacturing stations, helping to optimise production flow and minimise handling errors. Like all rotating machinery, motors have to be balanced to minimise vibration and optimise their performance, which is often completed on dynamic balancing machines. Many of the above production stages have to be carried out in cleanroom facilities and are increasingly monitored by in-line, quality-control equipment. In the continuum from prototype development to building small batches up to large-scale manufacture, handling options vary from the completely manual and mechanically assisted up to full automation (Image courtesy of Bosch)
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