一、 Why

1、电机功率大，工作电流大，发热量大。

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

2、风扇转速低，风压，风量小。

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

3、风扇叶片数较少，产生的风量小。

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

4、电动机附有灰尘、油污，降低了散热能力。

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

5、真空泵电机所在母线电压为380 V，由于电缆压降及负荷分配不均，电机实际所加电压只有365 V，电压偏低造成运行电流大。

5. The voltage of the bus where the vacuum pump motor is located is 380 v. due to the cable voltage drop and uneven load distribution, the actual voltage applied by the motor is only 365 v. the low voltage results in large operating current.

二、对策

二、 Countermeasures

电机功率、转速是和真空泵相匹配的，不能更改。风扇安装于电机主轴上，电机转速决定了风扇转速，也不可更换。增加风扇叶片数量虽能起到一定作用，但叶片数量增加后，动平衡不容易找，如找正不好，会引起电机振动增加。

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、将原风扇罩加长40 cm，在里面加装一个与风扇罩同直径轴流风机，轴流风机电机功率850 W，转速1 489 r/min，电压380V。原风扇继续保留。轴流风机另设一路电源控制，轴流风机与主电机不设连锁。真空泵启动后及时启动轴流风机运行，真空泵停运后30 min停运轴流风机，以使主电机得到充分冷却;

1. The original fan cover was lengthened by 40 cm, and an axial flow fan with the same diameter as the fan cover was installed. The motor power of the axial fan was 850 W, the speed was 1 489 R / min, and the voltage was 380 v. 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 min after the vacuum pump is shut down, so that the main motor can be fully cooled;

2、定期清除电机上灰尘，保持电机散热片清洁，增加其散热能力;

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

3、将真空泵所在母线电压调整为400 V。

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

三、效果

三、 Effect

1、由于轴流风机转速高，风压风量大，冷却效果大大增强，在相同的环境温度、负荷电流下，主电机温度下降了12℃。夏季主电机温度未再超限。

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、轴流风机可人为控制，主电机停运后，轴流风机仍可运行，可以使主电机得到充分冷却。

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、尽量使2段母线负荷分配平衡，以防某段母线因负荷过重造成电压下降过多。

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、电压调整后，真空泵运行电流降为210 A，发热量相对减小。

4. After the voltage is adjusted, the operating current of the vacuum pump is reduced to 210 A, and the calorific value is relatively reduced.

5、减缓了主电机的绝缘老化速度，延长了其使用寿命。

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