The versatile electric hand mixer makes kitchen work easier with the use of various attachments which can be turned at different speeds. Beaters can be used for whipped cream and cake batters. Whisks are used for mixing thick batters.
An electric hand mixer consists of the housing, a motor assembly, two pinion gears with spindles, a worm gear, a cooling fan, a speed control switch, an on/off switch, two beaters, a beater ejector system and either a power cord or rechargeable battery. Switches can be either mechanical or electronic.
With a supply of power to the motor and the beaters inserted, an on/off switch (generally on the front top of the mixer and readily accessible to the thumb) is moved or pressed to the first position. The beaters begin to turn at the slowest speed. The switch is then moved to a higher speed or back into the off position. Older mixers controlled the speed through the use of a sensitive governor switch. According to "Small Appliances" by Time-Life Books, "The rapid rotation of the motor armature activates a thrust rod, which repeatedly opens and closes the switch contacts to maintain precise speed control." Modern mixers do this with a electronic circuit board instead.
When the switch is turned to a speed setting, the motor assembly turns both a cooling fan and a horizontal worm gear. The worm gear, with angled grooves cut into the shaft, turns between two pinion gears connected to the vertical shafts of the beaters. This gearing configuration reduces the rotation speed of the motor to the slower mixing speeds while allowing the beaters to turn simultaneously at the same speed, but in opposite directions. It also changes the rotation of the beaters by ninety degrees from the motor. The separate clockwise and counterclockwise rotation is needed to draw the batter into and through the beaters.