Motor Overload Protection Feature of the Festool Shop Vacuum a.k.a. Festool Dust Extractor
The Festool CT 22 and Festool CT 33 dust extractors have dual thermal overload protection. When the machine gets too hot, it will turn itself off. There are not one, but two temperature sensors! One is attached to the field coil of the motor. This high temperature bi-metal switch hardly ever triggers because the motor is cooled independently with it's own fan. If the small vent on the right side of the machine were blocked, it might build up enough heat to trigger, or if the motor fails somehow and there was an internal short or current overload. Or maybe running on slow speed on a very hot day might limit the cooling air to the motor.
Festool Platinum Dust extractor
The other sensor is in the air flow coming out of the turbines. This sensor is called a –PT resistor”. It precisely measures the actual temperature of the exhaust air. And yes, it contains a small amount of Platinum! This platinum sensor is mounted in the flow of air coming out of the turbine pump. If the vacuum bag is full, or the hose is clogged, there can be considerable heat accumulating in the whole system, because the little air that does flow through the turbines is still being compressed, thus heated, and since it is not getting out of the machine as fast, there is more time for it to transfer its heat to the sensor. Also, there is not as much air moving thru the turbines and the blower itself is not cooled as well. The turbine housing is very close to this sensor.
If your Festool dust extractor shuts itself off while you are working with it, check the final filters, the filter bag and the hose for restrictions. If all of the above check out and the machine is outside in direct sunlight, try moving it into the shade. And, if troubles persist, please call Acetoolonline.com customer service at (516)783-8899