Belt Problems
A burning and smoke smell comes from the belt. When items such as cables, cords and other large objects are caught in the brush roller, it may fail to rotate. As the brush roller attempts to rotate, it begins producing smoke and a burning smell.
Solution
Move large objects and cables away from the brush roller. Remove the belt and reinsert it. If the belt is worn out or damaged, replace it according to instructions in your vacuum's owner's manual.
Maintenance
Remove hair, lint and other debris from the brush roller. Empty the vacuum bag or tank before it is completely full. Replace your air filter at least once a year. If your vacuum uses a HEPA filter, replace it every six to eight months. If you are using a canister vacuum, empty the canister before it is completely full. Depending on your vacuum model, you may need to empty it two to three times a year.