It sounds like you're trying to run it with the stock spindle motor. That was designed to run on US-style 110v 60 cycle electricity. If your mains current is 240v 50hz, there's some surplus energy building up in the motor as heat. But if it's been working for you for 10 years, it's probably going to keep working a while longer. If it finally does burn up, replace it with a locally-sourced continuous-duty fan-cooled spindle motor that weighs the same or less, and it will probably run cooler.