To disassemble the gearmotor, remove the panel with the contacts of the limit switch from the cover, unscrew the screws securing the gearbox cover and remove it together with the driven gear. The intermediate and drive gears are removed from the gearbox housing, then the screws securing the gearbox housing to the motor housing are unscrewed and disconnected. Take out the motor armature.
To remove the driven gear of the gearbox, unscrew the crank fastening nut and remove it. Remove the retaining ring from the axle and remove the axle with gear and washers from the cover. After disassembly, the internal cavities of the electric motor are blown with compressed air to remove deposits of coal dust and the condition of the brushes and commutator is checked.
The brushes must move freely, without jamming, in the brush holders, and the springs must be intact and have sufficient elasticity. The collector is cleaned with a sandpaper with a grain size of 10-M40, and then wiped with a clean cloth lightly greased with technical petroleum jelly. If the collector is badly burned or worn out, then it is better to replace the gearmotor with a new one. Check for signs of seizing on the necks of the armature shaft. If necessary, read them out with the same sandpaper.
The assembly of the gearmotor is carried out in the reverse order of disassembly. When assembling, the brushes are removed from the collector so as not to break them and not damage their edges, and the anchor is inserted into the housing with extreme care, avoiding hitting the poles so as not to break them. After assembly, it is recommended to tap the motor housing with a wooden hammer to center the bearings, and then check it on the stand.