To boost efficiency in the manufacturing of series-production motors at medium volumes, we’ve recently put a new automated winding system into operation. Our customers benefit from consistent quality and repeatable results: each motor winding is identical.
When production volumes reach a certain level, automating specific stages of manufacturing can help to promote efficient output. The heart of every electric motor is the winding inside the stator. At BEN Buchele, we typically wind stators by hand when working on custom orders or small batches. This process requires a great deal of expertise, from guiding the copper wires into the slots to lacing the windings.
For larger orders, such as the series production of switch actuators (about 4,000 units per year), we have recently started using a new system that automates the winding process. This system consists of four components: the coil winding machine, the insertion and preforming machine, the winding head press and the winding head lacing machine.
The Winding Process
The process begins with a preparatory step that is not directly part of the system: stator insulation. Here, the insulation papers (slot liners) are inserted into all the stator slots by machine.
In the first step of the main manufacturing process, the coils are made on the coil winding machine and transferred directly to the handling tool.
The second step involves inserting and preforming the coils. The coils that have been wound into the transfer tool are then handed over to the insertion tool.
Additionally, there is a manual workstation where the winding ends are connected to the terminal board, i.e. where the stranded wires are produced. Here, stranded wire and copper wire are joined together so the motor can be cleanly connected at the terminal board. This intermediate step takes place before the third process, the forming of the winding head.
Next is the winding head forming stage. The stator is pressed into its geometrically correct shape by a winding head press. Width, height and inside/outside diameter – i.e. the winding head geometry – must be precisely adhered to.
In the fourth step, the winding head is laced to fix its shape so that it retains its exact dimensions during intermediate storage.
The system can be used for motors from size 63 to 132 with a core length of 240 mm.
We currently manufacture size 80 for switch actuators and size 100 for crane motors. For each job, precisely fitting tools are required for all parts of the system, e.g. coil winding tools, insertion tools, winding head press tools and tools for the stator insulation. They must match the size and the stator configuration exactly.
Reproducible Quality
For our customers, automated winding for series motors is a major quality feature, since key parameters such as coil length, fill factor, winding head shape and lacing are precisely consistent in every stator, ensuring each winding is identical.
At present, our winding system is running in single-shift operation; in the medium term, we are planning for two shifts. This will enable us to manufacture several thousand windings annually.
Automation gives us greater flexibility in workforce planning, so that employees with specialized winding expertise can focus on individual and small-scale projects, where manual work is still required.
And this is what the fully wound stators of the switch actuators look like:
