Vacuuming With One Or Two Motors
There are two main types of upright vacuums - single motor and dual motor.
Single-motor units use the same motor to create suction and turn the beater bar. These models are generally cheaper, but prone to break down more because debris must pass through the vacuum belt and fan. However, single-motor units are also lightweight, making them useful for smaller and older workers because vacuuming is a tiring job, especially considering machines must be hauled on and off carts and transported to multiple rooms or even to different floors during a single shift.
Dual-motor vacuums use one motor to create suction and a second motor to turn the brush. Two motors make units heavier, but it also gives it more suction allowing janitors to suck up a majority of dust and dirt in one pass. In addition, machines break down less because the separate motors are protected from debris.