Opt for appliances with “brushless” motors for better air quality in your home
What? The dishwasher has a brush?
Ok, we realize that the term “brushless” may not be in most homeowners’ vocabularies, so we’ll explain that first. Our home appliances, small and large, run on many electric motors, which can be “brushed” or “brushless”, among other characteristics. Both types of motors have a stationary part and a rotating part, and both make use of permanent magnets and electromagnets. “Brushed” motors have been around for over 100 years. They have permanent magnets on the outside, which is also called the armature or stator. Inside, electric current flows in one direction through the brushes, which produces alternating positive and negative currents in the coils of the rotor. This process is called mechanical commutation. The alignment of the alternating currents in the rotor against the permanent magnets in the stator causes the rotor to rotate. The brushes, which are in constant contact with the rotor, are made of a soft material and wear down, requiring replacement. Where does the material go? Into the air as ultra-fine particles, or UFPs. UFPs by definition are less than 100 nanometers in diameter.
In brushless motors, the permanent magnets are in the rotor, which is driven by alternating positive and negative currents in the stator coils. The thin gap between rotor and stator eliminates the need to have brushes. These motors were developed in the 1960’s when computers could manage the precise electronic switching of the current, also called electronic commutation. Today brushless motors are available in many sizes and power requirements, but they tend to be a bit more expensive because of the electronic commutator.
In a recent study, however, the health benefits of brushless motors may put them firmly in the “better” category, when it comes to home appliances. Researchers measured the UFP output of brushed motors appliances. Gadgets with heating coils and brushed motors, like hair dryers and air fryers, produced 10-100 times more UFPs than brushless counterparts. UFPs are deposited predominantly in the alveolar region of the lungs (deep in the lungs where the oxygen and carbon dioxide transfer takes place with the blood, so that some UFPs may even pass into the bloodstream). (Ultrafine particles from small home appliances may pose health hazards)
If you’ve ever purchased an appliance and received extra parts that look like springs attached to grey rectangular pieces of metal, those are the brushes. The grey rectangular part, which is the part that’s actually in contact with the rotor and gets “worn down” is made of carbon or graphite, sometimes with some copper mixed in. These are the materials that get thrown into the air as UFPs.
Heat literally makes the brushes disintegrate faster than in non-heated appliances, and it now makes complete sense why inexpensive hairdryer motors “burn out” when they’re used frequently. Who is at most risk? Children, because they breathe more air per unit of body weight than adults. Those who use these appliances frequently, such as hairstylists in a salon, or home cooks using the air fryer, also are at risk.
In an article from the year 2000, it was determined that ultrafine carbon particles can induce slight inflammatory responses, and lungs of older subjects are at increased risk for ultrafine particle-induced oxidative stress. In addition, these inflammatory responses are greater with UFPs than with fine particles, because the UFPs have greater surface area.
We all have to replace appliances now and then, and these are the reasons to read all the “specifications” about the product. Brushless motors will help give you better air quality, which, if you have children, older people, or just use the appliance frequently yourself, would be an acceptable tradeoff for the slightly higher cost of the appliance.
Photo by Element5 Digital on Unsplash
