Hi Barkuti ,
We meet again on the electronic fields.., sorry to hear about your problems , but somehow , this should be the end of the myth that ANY ac dimmers are gone work , no matter what , with any load , resistive or inductive...
Some time ago I'd done the same "mistake".., in fact I tested the same module as your's , for a 1100W stand mount drilling machine , and with the same result :failed module ! I fact I was expected that , especially after I reversed engineered the schematic .( for some info of this , you have a video from Big Clive ,Reverse engineering of a mains power controller. - YouTube )
I ended up with installing an module recovered from a defective vacuum cleaner ( motor shorted )
This china made module is ONLY for resistive loads , as heaters and incandescent lamps , the manufacturer suppose to state this clearly , as many big and trustful companies does for their products .The question is : who is making these ? The answer : nobody knows !!!
But , more than that , checking the the conditions required for the QUALITY of the components used in a 220-240 Volts grid , I had my heart stop for a moment :is a killer module and if I have the power , I'll state this as a criminal act towards consumers !!!...
These said , I'd suggest you to look for a industrial power controller for vacuum cleaners (500-1000W) , as long as your Dremel has about 130W , any will work .
These ,has a truly zero detector , the gate of the triac is optoinsulated from the mains , and the snubber circuit is designated in a RCL grid , to avoid any spikes from the inductive loads . Probably , will be a little pricey (or you can do like me ,recovered one ), but once in place , will do its job with no problems !!!
For sure , you'll be able to find something like this at the repair centers , or ,maybe , you have already a defective vacuum , blender , pump ,kitchen robot , anything that has a variable speed motor... Cheers to you , too !!!