What Should I Do if the Motor Gets Wet?

In the actual production of many enterprises, it is often found that some electric vehicles have not been used up for a period of time. When they are activated again, it is found that the insulation resistance of the windings of electric vehicles is reduced, especially in the rainy season, when the air humidity is high, the insulation value of the electric vehicle may even decrease. If it drops to minus zero, it should be dried at this time, so that the insulation resistance and absorption ratio can reach the specified value. If it is put into operation rashly, it may break the insulation of the motor coil and cause an accident.

1. External heat source heating method

For the damp machine, first remove it, and then use a high-power incandescent light bulb to bake it inside the motor, or put it in the drying room to dry. This method is convenient, safe and reliable to operate, but it is only suitable for small motors and is easy to disassemble. For large and medium-sized motors or motors that are not easy to remove, the workload is relatively large, and the feasibility is also reduced. It should be noted that: when operating in this way, the light bulb or heat source should not be too close to the coil to prevent the coil from being burned out. You can cover the motor casing with items such as canvas to keep warm.

Second, the welding machine drying method

Before the drying method of the exchange welding machine is operated, connect the heads of the damped motor windings in series, and the casing is grounded, so that three sets of windings can be heated and dried. Whether the power consumption reaches the rated current of the motor~. The motor dried by the AC welding machine no longer needs to be dismantled and inspected, which reduces the workload. At the same time, when the power is turned on, the motor uses its own resistance to heat up, so that the coil is heated evenly, and the drying effect is relatively good, but this method is only suitable for the lower part. The motor cannot be used for a long time, because the electric current applied by the electric welding machine to the electric welding machine is relatively large, so it cannot be used for a long time, otherwise the electric welding machine may burn out.

3. The operation wiring of the drying method of the DC welding machine is similar to that of the AC, and the series meter should be a DC ammeter. Drying damp motors with a DC welding machine is easy to operate, and can dry large and medium-sized motors and high-voltage motors for a long time. Since the DC inverter welding machine is used now, it adopts the three-phase AC voltage after three-phase bridge rectification, filtering and supplying the inverter with a new type of power switching device for frequency conversion processing. After rectification, the output can be used to supply the power required for welding. Through the logic control circuit composed of integrated circuits, the feedback conditions such as voltage and current signals can be processed to realize the closed-loop control of the whole machine. The control technology with pulse width modulation as the core is adopted to obtain fast pulse Widely modulated constant current characteristics, there are also special cooling fans for cooling. In this way, when the welding machine works for a long time or works with high current, the internal components will not be damaged due to long-term high current operation, so it can be used for long-term use of large and medium-sized motors. It is worth noting that when drying, these two methods require that all contacts must be in good contact and tightened, the welding machine lead should be used exclusively for wires, and the cross-sectional size should meet the output current capacity of the welding machine. Pay attention to the cooling of the transformer of the welding machine itself, and at the same time ensure that the insulation resistance of the motor cannot be lower than that. It is also necessary to pay close attention to the temperature of the motor windings and adjust the voltage in time.

Summary: When the three-phase asynchronous motor is wet and dry, no matter what drying method is adopted, it is necessary to ensure the safety of personnel and the motor. This requires attention to the temperature and insulation resistance of the electric winding and iron core at any time during the processing process. Make sure that the temperature does not exceed the allowable value and make a record. When measuring with an infrared thermometer, the class insulation cannot exceed the class, and the class and class cannot exceed the class; if the resistance is measured, the level cannot be exceeded, and the level cannot be exceeded. When drying, the insulation resistance of the windings of the electric vehicle originally increased, followed by a decrease, and then increased again, in this way, until the insulation resistance value remains stable, the drying can be ended.