The Stromrichter Perma Drive Controller (PMD‑220 series) is a 4‑quadrant power conversion unit used to drive induction motors or variable frequency drives in industrial automation. Common failure modes for this class of controllers include over‑temperature shutdowns due to failing IGBT modules, insulation breakdown between the DC bus and chassis, and degradation of the gate driver circuitry leading to erratic motor response. Initial diagnostics should verify that the input voltage is within spec and that all fuses/MCBs are intact; inspect the DC bus for visible arcing or burn marks and check the output current transients with an oscilloscope; finally review any fault codes logged in the controller’s diagnostic memory.[oss-gpt-20b]