Reasons for failure identified
The Problem
- Violent rupture of case of main reservoir DC link capacitors supplying the traction inverters (1000V).
- The released material caused signifi cant collateral damage to the main bus bar and to the associated traction inverter.
- Similar failures had previously been investigated by the OEM, but the customer wanted an independent opinion; to understand the cause and whether any preventative measures could be taken.
Ingestigation
Component technology and characteristics identified.
- Typical failure modes examined against visual evidence of the failed capacitor.
- Several hypotheses were proposed and examined.
Results
- Most likely reason for failure was identifi ed along with possible aggravating factors.
- Recommendations given for further investigation, inspection and monitoring methods.
