the vacuum filter(s) are blocked,or may have partial pipe blockage this is causing the thermal overload to trip.
clean the filters, check the pipes.
black socks are a likely culprit you don't see them
wirecutterman
November 2009
They often have an overheat cut out switch that self resets. To stop the motor bursting into flames.
The filters may be blocked - the motor may be running too hot because of some electrical reason - the safety cut out may be acting prematurely.
Give it a clean and run it without the hose connected and see what happens.
Good luck...
Peccavi
November 2009
I can answer this question...
my hoover keeps cutting out .then ok after 15 mins?
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Try fixfault.com to fix vacuum cleaners.