Planex issue

[Worm Drive]

I had an issue with my new planex on its maiden voyage. After unpacking, I put it together in the shop and installed the soft pad and interface pad. I fired it up, all seemed well. At the job today, I started sanding in a closet. The 36 ac turned up all the way, speed 3, center hole suction at 3. I took one swipe up and down the wall and the sander shut down, red light flashing. I  figured that I had the motor at too low of a speed. After 5 mins I tried turning on the sander again it turned on, immediately slowed down and stopped. I called Festool, the only suggestion that seemed like a possibility was that something got caught under the sanding pad. I took it off, there was nothing under the pad. I turned the sander on with no pad and it worked fine. Reinstalled the soft pad, same problem. Installed the original pad and that worked fine. So, I tried the soft pad one more time, but only went finger tight with the bolt. I ran it for a couple minutes, all was well. Tightened the bolt, worked fine and has worked fine since. Not sure if the soft pad just needed to get ground in or what. I had ran the sander in my shop, with the soft pad and it seemed fine, but hadn't tried sanding anything. And yes, the pad was installed properly. Any ideas?

 

[Jeremiah9675]

Wow! I had the same experience only I had the original pad on and I never took it off. The red light is suppose to blink to indicate that the small ports or the fan in the motor is clogged with drywall dust and needs to be cleaned. I do that with a shot of co2 in a can if that's the problem. That fan cools the windings, armature, and brushes for the motor in the planex head. There is a temp sensor in it that senses if the windings on the rotor/commutator  are over heating due to to a clogged fan OR too much drag on the rotor (armature). If the drag is too high the brushes sit arching on the commutator  with the rotor spinning too slow, it over heats, the Sensor senses it and shuts off the planex. Technically the reason that Festool may tell you to clean the cooling fan is because if the fan cloggs with drywall dust the same problem will exist, over heated windings. The only difference is that instead of drag overheating the planex it is a cooling fan that isn't cooling the Motor.
My experience was just like yours! It did it at first, I got depressed, then it never did it again? My only guess is that the armature brushes needed to get broken in. What I mean is that the permanent brushes need to be concave to fit around the commutator on the armature and in sure that once it had arched enough it created a perfect concave fit on the commutator where the heat from the arching brushes were minimized greatly. That's only a guess but since my planex has worked for hours and hours flawlessly I'd say its a probable hypothesis. That having been said I have heard of guys saying that there Festool sanders (like the Rotex) have to be broken in for 8 hours of running time before they are manageable to use.  Technically it's more than likely the same thing. Not sure if this is what has happened to our planex sanders but if some one else can tell me why I'm open to suggestions.

 

[Jeremiah9675]

Also I forgot to point out that using the inner ring causes the pad to suck to the surface of the drywall hence causing even more drag the motor has to fight against.
Good luck, hope this helps.