Pre use inspection of electric motors
1.1 For newly installed and long-term unused motors, the insulation resistance of the winding to the casing must be measured before use, and must not be lower than the standard requirements. Otherwise, the motor must be dried until the insulation resistance meets the requirements before use.
1.2 Carefully check if all fastening bolts are tightened, if spring washers are missing, if all components of the explosion-proof shell are connected properly, if the grounding is reliable, and if the connection between the motor terminal and the cable is reliable. If any abnormalities are found, they should be dealt with in a timely manner.
1.3 Check whether the specifications and capacity of the explosion-proof starting equipment used for the motor meet the requirements, whether the wiring is correct, whether the starting device operates flexibly, whether the contact is good, and whether the metal shell of the starting equipment is reliably grounded.
1.4 Check if the three-phase power supply voltage is normal, whether the voltage is too high, too low, or if the three-phase voltage is asymmetric.
1.5 Choose mining rubber sheathed cables correctly based on the size of the motor current and usage conditions. According to the outer diameter of the cable, strip the rubber sealing ring introduced into the device into a hole of similar size, and then thread the cable into the pressure plate, metal gasket, sealing ring, and metal gasket in sequence. Connect the cable core wire to the terminal post. When wiring, the cable core wire should be placed between two bow shaped washers or pressure plates, and the grounding core wire should be placed between the bow shaped washers of the grounding screw, and should be reliably connected to ensure good contact and electrical clearance requirements. After connecting the wires, the junction box should be checked for debris, dust, and whether the connection method meets the requirements of the power supply voltage and the motor nameplate. Only after confirming that there are no errors can the junction box cover be tightened. The cable introduced into the junction box is fixed on the junction box bucket with a clamp to prevent the cable from being pulled out.
During the use of explosion-proof motors, inspection and maintenance personnel should regularly pay attention to the temperature rise of the motor, and should not use it beyond the temperature rise or operate it under overload; When the motor is running, the bearing temperature should be checked regularly. The bearing should be checked at least once after 2500 hours of operation. If the lubricating grease deteriorates, it must be replaced in a timely manner. Clean the waste oil inside and outside the oil filling and drainage device of the bearing to achieve cleanliness and smoothness. The bearing needs to be cleaned with gasoline and lubricated with No. 3 lithium based grease.