1、 Cause analysis

(1) The motor has high power, high working current and high heat output.

(2) Fan speed is low, air pressure, air volume is small.

(3) The number of fan blades is less and the air volume is small.

(4) Motor with dust, oil, reduce the heat dissipation capacity.

(5) The bus voltage of 2XZ rotary vane vacuum pump motor is 380V. Due to the cable voltage drop and uneven load distribution, the actual voltage applied by the motor is only 365v. The low voltage results in large operating current.

2、 Solutions

The motor power and speed are matched with the vacuum pump and cannot be changed. The fan is installed on the main shaft of the motor. The speed of the motor determines the speed of the fan and cannot be replaced. Although increasing the number of fan blades can play a certain role, but the dynamic balance is not easy to find after the number of blades is increased. If the alignment is not good, the motor vibration will increase.

(1) The original fan cover was lengthened by 40cm, and an axial flow fan with the same diameter as the fan cover was installed. The motor power of the axial fan was 850W, the speed was 1489r / min, and the voltage was 380V. The original fan remains. The axial flow fan is equipped with another power supply control, and the axial flow fan is not interlocked with the main motor. After the vacuum pump is started, the axial flow fan is started in time, and the axial flow fan is stopped 30 minutes after the vacuum pump is shut down, so that the main motor can be fully cooled;

(2) Regularly remove the dust on the motor, keep the heat sink clean and increase its heat dissipation capacity;

(3) Adjust the bus voltage of vacuum pump to 400V.

3、 Effect

(1) Due to the high speed of axial flow fan, large air pressure and air volume, the cooling effect is greatly enhanced. Under the same ambient temperature and load current, the temperature of main motor drops by 12 ℃. In summer, the main motor temperature did not exceed the limit.

(2) The axial flow fan can be controlled manually. After the main motor is stopped, the axial flow fan can still operate, which can make the main motor get sufficient cooling.

(3) Try to make the load distribution balance of the two sections of bus to prevent the voltage drop too much due to the overload of a section of bus.

(4) After voltage adjustment, the operating current drops to 210a, and the calorific value decreases.

(5) The insulation aging speed of the main motor is slowed down and its service life is prolonged.