Well it would not have been a short - open circuit perhaps but not a short. Shorts usually blow the fuse.
A common fault on appliances that get moved about is constant strain on the cable causing an inner conductor to slowly stretch until it breaks (open circuit). Laptop adapters and Vacuum cleaners suffer it - especially cleaners that get over enthusiastic tugging.
In a bad case you can sometimes feel the damage to the inner conductor with your fingers through the outer insulation.
I would guess that you have a broken conductor inside the cable - probably at the plug end (shorten the cable by 6") or perhaps at the other end.
If not - this may be a defective motor or overheat cut-out or on/off switch - but doubtful given what you report.
Good luck...
Peccavi
February 2010