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2017-09-11answer
Mitsubishi, An Chuan An Chuan, Wolong, Dayang Electric, Dechang, Jiangte Electric and other brands are all well-known brands, and they are all good brands in this industry in the list of the top ten brands of motors purchased online by China 10 brand. You can refer to them. When buying a motor, the following steps should be followed: (1) Check the appearance: the paint on the motor surface should be smooth and flat, the nameplate should be installed correctly and the signs should be complete; The heat sink of the enclosed motor base shall be intact and complete with accessories; ⑵ Manual rotation: When rotating the electric shaft by hand, it should be flexible, with good inertia and basically no axial movement; (3) Bearing diagnosis: After electrifying 15-25 minutes, the bearing should be smooth and light, and there is no sticking phenomenon. The sound is even and harmonious; The bearing temperature is not high, and there is no oil leakage or oil throwing; After the operation stops, touch the motor seat and end cover with your hands, so that you won't feel hot; (4) Check the wiring: open the junction box to see whether the phase line signs of each phase are clear and complete, whether the contact pieces are tight and whether the nuts are complete; ⑸ Measuring resistance: Measure the insulation resistance between the phase wires and between the wires and the frame at the outlet terminal with a manual megger with a rated voltage of 500v V.. The insulation resistance of normal motor should be greater than 1 megger. [6] Measure the current. In operation, the clamp ammeter is used to measure the current of each phase when the motor is empty. The deviation of any phase in the three-phase current should not be greater than 10% of the average value, and the no-load current is generally 25-50% of the rated current.