Buying used machine components requires caution – as demonstrated by a recent case in our workshop. About three weeks ago, a customer sent us a Yaskawa SGMSH-15ACA6C servo motor that he had purchased on eBay. The seller promised a refurbished product at an attractive price, with fast delivery and a warranty – perfect for keeping a spare in stock.

The Unpleasant Surprise

The motor remained untouched in storage for two months until it was urgently needed after a machine crash. The customer unpacked it without hesitation, as the eBay pictures looked promising. However, reality was different: the motor was heavily soiled, rusty, and far from what was expected. Nevertheless, there was no choice – the machine had to run.

The Fatal Consequences

After installation, the motor ran, but accompanying grinding noises were alarming. It remained in operation for two days, with the machine reporting errors every two hours. Eventually, the customer noticed a burning smell – a Yaskawa SGDH-15AE servo drive started smoking in the control cabinet. The situation was critical.

Our Diagnosis and Repair

The customer sent both the motor and the servo drive to us. Upon inspection, we found that the motor was close to a ground fault, which had put immense stress on the drive. The bearings were completely worn out, the brake had no lining, and the worn brake dust had contaminated both the stator and rotor. It was a small miracle that the encoder was still providing a clean signal.

Our team got to work: The motor was fully overhauled, fitted with new bearings, repainted, and equipped with a new brake. We were also able to save the damaged servo drive – only the transistor module and a few fuse resistors had to be replaced. Fortunately, no major fire damage had occurred.

Lessons from the Case

The customer tried unsuccessfully to contact the seller in China – eBay could no longer help as the complaint period had expired. This resulted not only in an unexpected financial loss but also in machine downtime and significant stress.

This case clearly shows that purchasing used components always carries some risk. Those buying from platforms like eBay should not rely solely on images but should thoroughly inspect components upon receipt to avoid unpleasant surprises and costly failures.

Do you have any questions or need assistance with repairing your machine components? Contact us – we are happy to help!