Motor
Motors used in most vacuum cleaners are specifically engineered for the purpose. The design may vary depending on the design of the vacuum cleaner however in most cases they run directly off mains AC power, either 110 or 230 volts depending on the market they are produced for.
Typically the motor in a vacuum cleaner rotates at high-speed up to and even beyond 30,000rpm, which is an order of magnitude faster than the typical car, washing machine, or computer fan.
Most modern vacuum cleaners utilise an off the shelf vacuum cleaner motor manufactured and designed by a third party company. Almost all of these motors feature a built in impeller which produces the suction, and some form of in-built cooling. The only known exception to this is Dyson's recent digital motor design which is detailed later.
There are several common variations on the design for a vacuum cleaner motor, primarily the designs are all based around a high speed brushed AC motor which runs off 110 or 230 volt mains.
Some vacuum cleaner motors maintain separate cooling and suction channels, this requires the addition of a smaller secondary fan on the motor to cool the motor itself.
Most modern vacuum cleaners combine their vacuum power and cooling by exhausting the air through the motor components and then out to the outside world. This has the benefit of being a simpler design but can mean the motor is susceptible to overheating if the inlet is blocked, and means the air must be entirely clean before hitting the motor otherwise dust, and dirt could build up in the motor causing damage or creating a fire risk.
For upright vacuum cleaners it is necessary to provide an additional output shaft on the exhaust end of the motor to provide through a belt to the powered brush bar. This means that the motor will suffer some drag from the brush bar and potentially not spin at it's absolute fastest, however the effect is likely negligible.
When designing your vacuum cleaner you can utilise any type of motor in your design but you must be aware of keeping this additional shaft protected as it is rotating at high speed and could cause injury if it caught something.
In the past few years Dyson have started using their 'digital motor' inside new products, these motors work on high voltage DC and spin up as fast as 100,000rpm. These motors use a fundamentally different approach, utilising a brushless DC motor controlled by a micro-controller. They also use a 3D impeller design which differs significantly from the typical 2D impeller used in most vacuum cleaner motors.
Now that you are familiar with the various types of motors and how they work it is important to remember that the motor is the most fundamental part of your vacuum cleaner design and choosing the right motor is very important. Also it is important to note that these motors can be dangerous because of the forces they are subjected to and the mains electricity they are powered by.
After much consideration in relation to the principals of design, I worked with a company called eSpares to figure out which motor was most likely to be around the longest, because if it broke in the future I wanted it to be a likely contender for easy replacement either with a fake of genuine part.
eSpares started by recommending a Dyson brand part because Dyson have a smaller range of products to maintain support for. They identified a YDK brand motor YV-2200 which is used in both the Dyson DC07 and DC14, which were produced several years in a row meaning there is likely to be a large number of spares available for a long time. Also because they are intended for upright vacuum cleaners they can be used in almost any design of vacuum cleaner.
I was able to find a clone part on eBay for about £22 but the original can be bought for £43 from eSpares.