The Sevcon Millipak 633T45323 is a high‑current (≈500 A) 48 V motor controller used in forklift and industrial lift applications. Common failure modes for this model include thermal runaway of the IGBT array, loss of phase current sensing due to damaged Hall sensors or wiring insulation breakdown, and firmware corruption that triggers fault codes such as “Over‑temperature” or “Phase imbalance.” Initial checks should verify the 48 V supply voltage and ripple, inspect all power‑stage connectors for corrosion or loose contacts, and review the controller’s diagnostic LED/serial log for specific error codes. If a fault code is present, cross‑reference it with the Sevcon manual to determine whether a reset, firmware update, or component replacement is required.[oss-gpt-20b]