The burning smell is unlikely to be the motor.
Google for "Kenwood Chef A701 speed controller repair"
Try http://howtomendit.com/answers.php?id=45632
The most likely source of the burning smell is a failing capacitor of overheated resistor, but those two links will give you more details.
Repair is relatively simple, but you will need to replace some components, and the ability to solder is required. These machines, unlike their modern equivalents are designed to be relatively easy to service.