Although all motors are tested at the Vitamix factory, heavy use will cause further curing of the motor windings in new machines. This curing gives off a burning smell and is typical for wound motors. This smell will quickly dissipate after a few heavy uses.
In addition, the Vitamix motor is designed with Automatic Overload Protection to protect itself from overheating. If the motor should overheat, it may emit a burning smell.
If this occurs, turn the power off for up to 45 minutes, allowing the machine to cool down or reset. Reset time will be extended if high room temperarutes exist. To reduce the reset time, remove the container, unplug the machine, and use a hair dryer on the cool setting to blow air into the center section of the bottom of the motor base.