The motor may be overheating because the air flow is blocked. The over temp cut-out is doing what it is supposed to do. Check ALL the pipes that remove easily first (the U-BEND pipe etc, ensure clean ans not blocked), then remove the cyclone compartment (bin), remove the clear outer part, and check that the central internal cylindrical part is not blocked up. Use a friends vacuum to clear it out. Occasionally the top gets very clogged. Some people HOSE them out to avoid unscrewing the top, but you will need to wait 1 day for it to dry in the airing cupboard. ALSO: check the blue spongy filter that sits under a round holder under where the bin sits. It can be hard to prise off. The filter can be washed in soapy water, BUT ENSURE IT IS FULLY DRY B4 USE. DON'T WASH THE WHITE HEPA FILTER!!
TD1947, October 2006