Polish Table Grinder Electric Motor Buzzing: Addressing Overheating & Startup Issues after 15-20s

I have a Polish table grinder When the engine was cold it worked normally, after 15-20 seconds of operation it became warm. I turned it off and on and it did not work anymore, i.e. it buzzed and refused to walk. Sometimes when I move it with my hand it will start to work (but this is rare, when it is not too warm) After cooling down, it works normally ...
Can anyone help me?

A colleague checked capacitor?

Capacitor for replacement.

I checked the capacitor and it's good, I even gave it a different one, a little bigger and the same

Is it spinning lightly? bearings ok? specify motor power and what capacitor?

The bearings mounted on the grinder shaft are their outer rings embedded directly in the plastic grinder housings in which there are no retaining rings, as a result of which during the grinder operation the temperature increases inside the grinder body and thus the temperature is transferred to the side of the grinder's body and thus friction of the motor rotor on the stator plate and stopping the rotor itself and the engine humming. I had the same problem. The manufacturer clearly stated how many minutes the grinder can work so that the motor shaft does not stop when the grinder motor overheats. I just gave up in the form of buying a new grinder power 200W in Lidl at a moderate price not exceeding PLN 100. In other stores I was offered 120W grinders, which I did not like.

I had cleaned the bearings before because they were dirty and loose. Motor power is 180 W and capacitor 3.7 uF

After all, the motor of this grinder is closed in a closed housing where there is practically no cooling, which changes the parameters of the housings, their heating and decalibration of the dimensions of the holes in the housings of built-in bearings, so that the rotor begins to rub against the rotor plates and becomes the grinder's rotor. up to several minutes. After the grinder has cooled down completely, it can be used again until it stops again by itself, which causes its humming.

When the temperature increases, there is a loss of rotor alignment with respect to the stator on plastic bearing seats and the rotor rubs against the stator.

I started it yesterday, as I wrote earlier, to clean the bearings, and I am reminded that there were scratches on the rotor ....
But it can work a few minutes until it stops, not a few seconds.
And after 15 seconds it doesn't work, although the rotor turns slightly, but it is hot

A new axle must be added to this grinder, because the mounted one does not pass through the rotor but consists of two parts embedded in a plastic sleeve. Former material saving.