Electric Motor Repair Case Study Part 1:Inspect, Measure, DIsassemble

When a motor core makes its way to the shop, a few things need to happen before any lamination process can occur. First, a customer’s motor core requires inspection, measurement, and disassembly to prepare engineers for reverse engineering. This process ensures optimal outcomes because no motor has a one-size-fits-all fix. Let’s walk through each step in more detail.
Inspect
To begin, experts closely examine the motor core to assess damage and wear that would require replacement. Here are a few indications of wear often seen in an motor core:
Damaged laminations
Bent teeth
Missing material
Misalignment
Loose teeth
While this step does not impact the actual lamination process further down the line, it does help engineers understand how the motor was damaged and anticipate any challenges with disassembly after measurement.
Measure
Once the inspection is complete, the motor core is taken over to the engineering department for measurement. One of the critical measurements is overall stack length. This dimension measurement will go onto the final drawing and is what the core will be made to match. Slot and width depth are also measured. All measurements are taken from multiple locations on the core using calipers to ensure accuracy.
Disassemble
The next step in reverse engineering is removing the stator core. This is often done by heating the whole unit and pulling the core out of the frame. However, assembly varies, so it’s essential to explore how each core is put together for proper disassembly. For example, if pins hold the core to the frame, a drill press may be used to remove said pins and slip the core from its frame.
After disassembly, a few lamination samples are taken to a coordinate measuring machine, or CMM, for accurate measuring before a CAD drawing can be rendered.
See Case Study Part 2 for the next step in the electrical motor repair process.