When the motor shell is used in decoration or some special occasions, the surface of the motor shell needs to be anodized and coated to obtain the corresponding color and surface structure. The application of motor shell casting is very common, and its production difficulty depends on the structure, size and technical requirements. The motor shell is used in foreign electric locomotives, and the casting surface quality and internal quality requirements are high. This paper introduces the casting technology of motor shell.
The motor shell casting is not a very complete cylinder. There are many subsidiary structures such as laps on the cylinder body. The wall thickness of each part of the casting changes greatly. The stress of the casting during cooling and solidification is also relatively large. The deformation tendency of the casting can not be accurately predicted before. The diameter difference of the end of the straight cylinder is 15mm, and the ellipse is serious. The diameter error of the end of the straight cylinder is less than 1mm by setting the ring-shaped reinforcement at the end of the straight cylinder.
The inner cavity of the upper part of the casting is more complex, and there are more local bumps; therefore, there are many "t" and "L" hot spots in the casting, so it is difficult to feed the castings. The molding operation is relatively simple, but the feeding of the motor housing casting is very difficult, especially for the convex part of the upper cavity with complex structure, there is basically no measure to solve the feeding problem. The riser is set at the upper end, but the casting wall is thick, the bottom is thick and the upper part is thin. In addition, the casting is higher, so it is difficult to feed the lower part. In addition, the deformation of casting is also a problem to be faced.
The selection of rated power of motor case is a very complex problem. When loaded, if the rated power of the micro motor case is too large, the motor shell will often be in light load operation, and the capacity of the micro electric casing can not be fully utilized. At the same time, the operating cost will be increased due to the low operating efficiency and poor performance of the micro electric casing.
If the rated power of the motor shell is small, the current of the motor shell exceeds the rated current, the loss in the micro electric shell will increase, the efficiency will be low, and the life of the motor shell will be affected, and the insulation performance of the insulation material of the micro electric shell will be destroyed or even burned. Of course, the rated power of the motor shell is small, it may not be able to drag the load at all, which will make the motor shell in the starting state for a long time and cause overheating damage. Therefore, reasonable selection of power and correct maintenance of the motor shell is essential.
In the process of motor operation, due to the role of friction, the motor shell will produce some heat, if the motor shell overheating will damage the normal operation of the motor, so the motor shell will have a lot of blades or fans and lubricating oil to cool the motor shell, then what kind of problem is reasonable for the motor shell? We need to explain this problem from different types of motors
1. AC motor for explosion proof applications
If it is to drive a high-speed oil pump, such as a 2-pole motor with more than 2890 revolutions, the temperature is not higher than 85-90 degrees. Because it is a high-speed motor, the temperature is generally controlled below 80 degrees in summer, exceeding the shutdown (considering the insulation level of the insulation coil). Also because the motor is running in dangerous and explosive situations, in order to ensure the explosion-proof inspectors once half an hour, the specific measurement: Motor surface temperature, controlled within the temperature.
2. AC motor for ground non explosion proof applications
For example, for the commonly used 4-pole and 6-pole motors, as long as the motor speed is low, the bearing should be lubricated frequently. If the motor is more than 4-pole, the temperature of the motor shell should be kept at 70 ℃. Bearing temperature over 80 degrees, is the cause of oil shortage, regular maintenance.
Measuring position: Motor surface (high temperature near lifting ring) motor bearing (side bearing cover surface).
3. DC motor
Because most of the DC motors are equipped with cooling fans, the temperature is controlled within 50 degrees, which is 60-65 degrees higher in summer.
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