The insulation sleeves of the motor parts are intact and free of cracks and looseness. The lead connection should be firm, and the insulation resistance value should not be lower than 0.5MΩ when the working temperature is 75℃. In terms of the brush device, the lower edge of the brush box is required to be 2~4mm away from the surface of the motor parts. If the distance is too large, the brush will jump in the brush box. If it is a hard brush, it is likely to be broken. The brush should slide flexibly in the brush box, the surface of the inner hole of the brush box is smooth, the inner diameter tolerance of the brush box is H10, and the axial size tolerance is H8. Dimensional tolerance of brush width and thickness d11. The gap between the brush and the brush box wall should be 0.1~0.2mm. If the gap is too large, the brush will swing tangentially in the brush box, which will affect the normal operation of the motor accessories; if the gap is too small, the brush will be stuck in the brush box, causing similar The arc of the electric welding burns the surface of the copper ring.
When overhauling, the motor accessories should be carefully inspected: whether the working surface of the motor accessories is smooth and whether there are defects such as burn marks and streaks. The working surface is required to be smooth and free of rust and grease. The external binding of the insulation of the motor accessories should be correct and the coating should be good. If it is not handled well, use synthetic resin-impregnated non-lattice glass ribbon for binding to prevent leakage of mica flakes when the motor is running. The matching of the motor parts and the shaft and the matching of the rings and the insulating sleeve should be firm. Use a small hammer to tap the matching place between the copper ring and the copper sleeve, and there should be a metallic sound.
The brush and the ring should be in close contact. The pressure difference between the brushes should not exceed 20% of its average value. For the wound rotor asynchronous motor with brush lifting device, the electric shock on the short-circuit ring is in uniform contact with the blades on the motor accessories, and the contact area is more than 60%, avoiding the single-phase operation of the rotor or the loss of elasticity of the contacts due to overheating. For minor burn marks, pitting, brush marks and other defects on the surface of the motor parts, use oilstone and fine files to polish them, and finally polish them with a zero or zero emery cloth. Under normal circumstances, motor parts should not be turned easily, because turning once will reduce a lot of life.