Treatment Scheme of All Insulating Materials for Motor


Firstly, the motor is returned to the workshop and disintegrated. After the rotor is pulled out, it is found that the insulation material on the stator coil has small cracks and micro-L, so the moisture is easy to enter the coil, resulting in the reduction of the stator insulation of the motor.
Because the protection form of the motor is open, dust and sludge will enter the stator winding from the end and side of the machine base. The dust in the stator will be blown clean by the blower. The sludge in the stator coil and the surface of the iron core will be thoroughly cleaned by CCIA (carbon tetrachloride) or SS-125 (cleaning agent). The winding and the surface of the iron core will be wiped clean by cloth.
Pre-drying, also known as pre-drying, is to remove moisture in windings and insulation materials. Pre-drying must be thorough, which is the key to restore the insulation performance of windings. The maximum temperature depends on the insulation level of the motor. In principle, the pre-baking time should ensure that the insulation resistance of windings reaches a certain stable value until the insulation resistance value no longer increases. If the pre-baking temperature is too low or the pre-baking time is too short, the insulation resistance will not increase much. Even if it is increased, because the moisture is coated with insulating enamel in the inner layer, when the motor is running, under the action of voltage, it is easy to produce ionization effect and cause accelerated insulation damage.


At the same time, the heat generated by the winding is not easy to emit, which affects the heat dissipation of the motor and increases its temperature rise, thus shortening the service life of the motor. The stator is put into the oven by the multi-stage heating method, that is, the heating temperature rises step by step, every 8 hours rises 5 C, the A-class insulated motor rises to 90 C, the E-class insulated motor rises to 100 ~C, the B-class insulated motor rises to 110 ~C step by step, and the tide-driving temperature is not too high, because the expansion coefficient of conductor material and insulating material is different, if the heating temperature rises suddenly, the stator wire will be made. The small cracks on the insulating material on the coil enlarge and reduce the inherent insulation strength and mechanical strength of the insulating material. Because the insulation grade of the motor is B, the limit temperature rises to 130 C, and the temperature rises gradually from 60′: C to 110 C. The maximum temperature of the temperature rises should be lower than 15-20 C of the permitted temperature of the motor. The insulation resistance should be measured every 1 hour. After the insulation resistance is stabilized, the pre-baking should be finished.

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