The Nutri-Tech Motor
The unit is air-cooled. Air-cooling in this case is appropriate because air is passing over the motor at all times when the unit is operating. In the case with the Nutri-Tech unit, the unit motor includes two sealed bearings that are sealed in grease for purposes of keeping dirt out of the bearings and help keep the motor running cooler and smoother at all times. Heat typically is only a concern when by some chance the filter is not replaced timely. All Nutri-Tech air-cleaning systems have thermal protection built into the motor. The thermal protection is a safety mechanism that automatically shuts the motor down if the motor ever gets too hot due to the filter being totally plugged and no air is passing through the unit., Although, due to the sealed bearing system, even with a plugged filter, the motor hardly ever would get too hot if the filter is plugged. Thermal protection was built into the motor just as an extra precautionary measure.
It is important for BelKraft's sales people to understand that 99% of all competitive units sold in the market do not include sealed ball bearings in the motor. Most competitive units contain a motor that utilizes two oilite bushing. When a motor using Ollie bushings get hot, due to the filter not being replaced timely, this impregnated oil in the bronze bushing drains out of the bushing. The bronze oilite bushing then seizes up on the mortar shaft. When the oilite bushing seizes up the motor shaft, the motor overheats and burns out. This is the most common problem Holmes, Honeywell, Duracraft and other manufacturer face with this air cleaning systems. Although competition has approached this matter as tough it is not a design problem. They have considered motor failure as customer abuse of the product because if the motor quits for non-replacement of the filter cartridge, the customer has not met the criteria under the limited warranty and care of the product.
Nutri-Tech units have a superior motor built into it's compact and console air-cleaning systems. I hope this clearly answers your questions.