Analysis of the reasons for high temperature in vacuum pumps

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Originating from the internet: Analysis of the reasons for high temperature in vacuum pumps. The following is an analysis of the reasons for high temperatures in vacuum pump motors: 1. Reason analysis: (1) The motor has a high power rating, resulting in high operating current and thus significant heat generation. (2) The fan rotates at a low speed, resulting in low air pressure and low airflow. (3) The number of fan blades is low, resulting in a low air volume. (4) The motor is covered with dust and oil, reducing its heat dissipation capacity. (5) The voltage on the bus bar where the vacuum pump motor is connected is 380V; however, due to cable voltage drops and uneven load distribution, the actual voltage applied to the motor is only 365V. This lower voltage results in a higher operating current. 2. Countermeasure: The motor power and speed are matched to the vacuum pump and cannot be changed. The fan is mounted on the motor shaft; the speed of the motor determines the speed of the fan, and it cannot be replaced. Increasing the number of fan blades can help to some extent, but with more blades, it becomes more difficult to achieve dynamic balance; if alignment is not proper, it can lead to increased vibration in the motor. (1) Extend the original fan cover by 40 cm, and install an axial flow fan with the same diameter as the fan cover inside; the motor of this axial flow fan has a power of 850 W, a rotation speed of 1489 r/min, and an operating voltage of 380 V. The original fan remains in place. The axial flow fan is equipped with a separate power supply for control, and there is no interlock between the axial flow fan and the main motor. Start the axial flow fan promptly after the vacuum pump begins operating, and shut it down 30 minutes after the vacuum pump stops, so that the main motor can cool down adequately ； (2) Regularly remove dust from the motor and keep its cooling fins clean to improve its heat dissipation capacity ； (3) Adjust the bus voltage where the vacuum pump is located to 400V. 3 Effects: (1) Due to the high speed of the axial flow fan, which results in high wind pressure and volume, the cooling effect is **enhanced; under the same ambient temperature and load current, the temperature of the main motor decreases by 12°C. The temperature of the main motor during summer has not exceeded the limits again. (2) The axial flow fan can be controlled manually; even after the main motor stops operating, the axial flow fan can continue to run, thereby ensuring adequate cooling for the main motor. (3) Strive to keep the load distribution between the two busbars balanced, in order to prevent excessive voltage drop in any one busbar due to excessive load. (4) After voltage adjustment, the operating current of the diaphragm pump dropped to 210A, resulting in a relative reduction in heat generation. (5) It slows down the insulation aging of the main motor, extending its service life.