There are many kinds of problems with concrete mixers, such as engine problems, hydraulic system problems, circuit problems, operation valve problems, etc. concrete mixers give us an introduction to the problems that need to be paid attention to when they need to be repaired? The first thing to do is to cut off the power. Before the power is cut off, the incineration switch should be closed, and the electrical equipment, such as audio equipment, should also be closed. It is forbidden to cut off the power suddenly when the electrical equipment is running. The detailed power-off sequence is as follows: safety first, so in the maintenance time, the negative pole should be removed first, and then the positive pole. The time sequence of the device is opposite, the positive pole should be installed first, and then the negative pole.

为什么先断负极呢？混凝土搅拌机在这里给我们解释一下：

Why cut off the negative first? The concrete mixer is here to explain to us:

1. 先拆正极存在烧坏电器元件的风险，简单引起电脑板烧毁的丢失。在电路的实践维修过程中因违反操作规程，损坏电路和把手烧伤的人很多，由于蓄电池正负极短路电流非常大，能瞬间产生高温。

1. There is a risk of burning out electrical components by removing the positive electrode first, which will easily lead to the loss of computer board. In the process of practical maintenance of the circuit, there are many people who damage the circuit and burn the handle due to the violation of the operation rules. Because the short circuit current of the positive and negative electrodes of the battery is very large, it can produce high temperature instantly.
              

2. 假如先拔掉正极，因负极是搭铁的，也便是正极周围的金属车体都是负极，假如用东西拆开正极接线时，东西碰到周围的金属车体，就会形成蓄电池正负极短路。

2. If the positive pole is pulled out first, because the negative pole is grounded, the metal car body around the positive pole is negative pole. If the thing touches the metal car body around when the positive pole wiring is disconnected, it will form a short circuit between the positive and negative poles of the battery.

3. 假如先拔掉负极，因负极周围的金属车体与负极是连通的，即便东西碰到也不会产生什么坏的结果，当负极拔掉后已经断电，再去拔正极就不会有什么风险了。

3. If the negative pole is pulled out first, because the metal car body around the negative pole is connected with the negative pole, even if something touches it, it will not produce any bad results. When the negative pole is pulled out and the power has been cut off, there will be no risk to pull out the positive pole again.

混凝土搅拌机要留意一点：现行的搅拌车的蓄电池都是有总开关的，可是原来的都没有，就欠好操作；并且假如是风险品运输车，比方油罐车，车上的行车记录仪是不允许断电的，断电后行车记录仪不能工作，车主或许就要承担法律责任了，可是假如是风险品运输车，可以在车上放置一个供行车记录仪的备用电源，这样即便电路呈现毛病，也不于让行车记录仪断电。

The concrete mixer should pay attention to the following points: the battery of the existing mixer has a master switch, but the original one does not, so it is not easy to operate; and if it is a risk goods transport vehicle, such as an oil tank vehicle, the vehicle's dash cam is not allowed to power off, and the car owner may have to bear legal responsibility if the power is off, but if it is a risk goods transport vehicle, the car's dash cam is not allowed to work Car, you can place a standby power supply for the dash cam in the car, so that even if the circuit is faulty, it will not power off the dash cam.