Blender Motor Basics
The motor of a blender is generally quite basic, being a small air-cooled electric motor situated in the housing of the blender unit. The motor is situated so that when it is in operation, it causes a small vertical coupler shaft to spin at a high speed. Many blenders use the motion of the motor itself to draw in air through ventilation holes in the housing to help keep the motor cool, though some blender motors have a small fan attached to them in order to keep cooler air flowing over the motor components. Most blender motors are not designed for sustained use; while they are able to provide power to the blender in short bursts over a long period of time, keeping the motor running continuously over a period of time can lead to overheating, which may cause the motor to shut down temporarily or lock up completely. Different blenders use different amounts of power, with relatively basic blenders having a 450-watt motor while more complex blenders may feature 750-watt motors or higher.
Controlling Motor Speed
Though single-speed blenders do exist, the majority of blenders are designed to accommodate multiple blending speeds. Changing the speed of the blender is done by means of a series of buttons or a switch, with each setting altering the amount of power provided to the motor. The lower the amount of power provided to the motor is, the slower the motor will spin the coupler that connects to the blades. Likewise, the higher the amount of power provided to the motor is, the faster the coupler will spin and the more powerful the blender blades will be. Some multi-speed blenders only feature 3 motor speeds (low, medium and high), while others may feature anywhere between 7 and 18 settings (everything from "crush" to "liquefy," sometimes in both low and high power settings.)
When the blender motor is active, the coupler shaft attached to the blender motor spins at high speeds; the blades within the blender jar attaches tightly to the coupler, causing the blades to spin at the same speed as the coupler shaft. The motion of the blades creates a vortex like a whirlpool within any liquid contained in the blender jar, causing any solid materials to be pulled down toward the blades so that they can be chopped and circulated back up toward the top of the liquid. By pulsing the motor instead of having it run continuously, the blades can avoid having solid materials build up around them. Pulses and changes in speed result in more thorough blending and a more uniform mixture of the blended material throughout the jar. In order to avoid unnecessary wear on the blender motor, the blender should be thoroughly cleaned after each use.