- 货运电动三轮车电动机不转
故障现象：电动机不转。
分析检修：首先检查连线正常，测电动机定子绕组正常，转子绕组不通，检查发现碳刷磨损严重，更换碳刷，测转子绕组正常，接通电源，试车，电动机运转正常。
- The Motor of the Freight Electric Tricycle Doesn’t Rotate
**Fault Phenomenon**: The motor doesn’t rotate. **Analysis and Maintenance**: Firstly, check that the connection wires are normal. Measure the stator winding of the motor and find it to be normal. However, the rotor winding is open-circuited. Upon inspection, it is found that the carbon brushes are seriously worn. Replace the carbon brushes and measure the rotor winding again, which turns out to be normal. Then connect the power supply and conduct a test run. The motor operates normally.
- 货运电动三轮车只能前进不能退
故障现象：电动三轮车只能进不能退。
分析检修：根据原理判断是正、反开关坏了，更换后，电动三轮车正常。
- The Freight Electric Tricycle Can Only Move Forward but Not Backward **Fault Phenomenon**: The electric tricycle can only move forward and cannot move backward. **Analysis and Maintenance**: Judging according to the principle, it is determined that the forward and reverse switch is broken. After replacing it, the electric tricycle operates normally.
- 货运电动三轮车电动机运转，电源线发热严重
故障现象：电动机运转，电源线发热严重。分析检修：首先测电源电压正常，判断发热一定是电流太大造成的，经询问用户，原来这辆车的正、反开关是用户自己更换的。用万用表蜂鸣器挡测量正、反开关开关上4根线，两根相通的是电动机定子绕组线，测量有10kΩ阻值，是与控制器和电动机转子相连线，定子绕组的两根线应和两个动片相连，万用表一测，线接错，重新接好，试车，电动机运转，电源线不发热。
3.The Motor of the Freight Electric Tricycle Runs While the Power Cord Heats Up Seriously
**Fault Phenomenon**: The motor runs while the power cord heats up seriously.
**Analysis and Maintenance**: Firstly, measure the power supply voltage and find it to be normal. It is judged that the heating must be caused by excessive current. After inquiring the user, it turns out that the user replaced the forward and reverse switch of this vehicle by himself. Use the buzzer range of the multimeter to measure the four wires on the forward and reverse switch. The two wires that are connected to each other are the wires of the motor stator winding. The measured resistance is 10 kΩ, which belongs to the wires connected to the controller and the motor rotor. The two wires of the stator winding should be connected to the two moving contacts. When measured with the multimeter, it is found that the wires are wrongly connected. Reconnect them properly, conduct a test run, and the motor runs without the power cord heating up.
- 货运电动三轮车转向不灵
故障现象：转动转把转向不灵。
分析检修：由于转向轴过紧，致使转向阻力增大，需要调整转向轴，压紧螺母至适当位置；若转向轴轴承损坏也会导致转向不灵活，换上新轴承即可解决；对于方向盘式的三轮车，则可能是方向机内缺了润滑脂，需要定期加入润滑脂；若方向机的轴承调整过紧或方向机内的齿轮与齿条啮合太紧，也会导致转向不灵活，这时需重新调整。
4.The Steering of the Freight Electric Tricycle Doesn’t Work Well **Fault Phenomenon**: When turning the throttle grip, the steering doesn’t work well. **Analysis and Maintenance**: As the steering shaft is too tight, the steering resistance increases. It is necessary to adjust the steering shaft and tighten the nut to an appropriate position. If the bearing of the steering shaft is damaged, it will also lead to poor steering. Replace it with a new bearing to solve the problem. For the tricycle with a steering wheel, it may be that the steering gear lacks grease, and it is necessary to add grease regularly. If the bearing of the steering gear is adjusted too tightly or the meshing between the gear and the rack in the steering gear is too tight, it will also lead to poor steering. At this time, it is necessary to readjust.
- 货运电动三轮车跑偏
故障现象：电动三轮车跑偏。
分析检修：
（1）如果前轮负荷过大，或者货厢载荷偏于一侧，三轮车就会跑偏。所以用户装货时，应将货物均匀放置，避免意外事故的发生。
- 若前轮气压过低，左右后轮气压差过大，也会导致三轮车跑偏。这时应将前轮气压充至标准值450kPa，后轮气压充至550kPa，并使两轮的气压值相等。
- 减震器左右弹簧弹性不一致或减震器不平行，工作长度不一致会导致三轮车跑偏。这时须检查两弹簧的规格是否一致或更换失效的弹簧；减震器不平行、工作长度不一致则应重新安装；若减震器的轴弯曲，应拆修更换，直到其平行，工作长度一致。
- 左右板簧弹性不一，也会导致车跑偏，这时需更换板簧才能解决。
- 平行拉杆长度不一，两边受力不均，也是导致车跑偏的一大原因，这时需调整平行拉杆至长度相同。
- 由于撞车致使车架变形，引起转向套倾斜，角度变化，也会导致车跑偏。这时应予以校正，若大梁倾斜扭曲严重，则需要换新的大梁。
5.The Freight Electric Tricycle Runs Deviated **Fault Phenomenon**: The electric tricycle runs deviated. **Analysis and Maintenance**: (1) If the front wheel load is too large or the load in the cargo box is biased to one side, the tricycle will run deviated. Therefore, when loading goods, the user should place the goods evenly to avoid accidents. (2) If the air pressure of the front wheel is too low and the air pressure difference between the left and right rear wheels is too large, it will also cause the tricycle to run deviated. At this time, the air pressure of the front wheel should be inflated to the standard value of 450 kPa, and the air pressure of the rear wheels should be inflated to 550 kPa, and make the air pressure values of the two wheels equal. (3) If the elasticity of the left and right springs of the shock absorber is inconsistent or the shock absorbers are not parallel and the working lengths are inconsistent, it will cause the tricycle to run deviated. At this time, it is necessary to check whether the specifications of the two springs are consistent or replace the ineffective springs. If the shock absorbers are not parallel and the working lengths are inconsistent, they should be reinstalled. If the shaft of the shock absorber is bent, it should be disassembled, repaired or replaced until it is parallel and the working lengths are consistent. (4) If the elasticity of the left and right leaf springs is inconsistent, it will also cause the vehicle to run deviated. At this time, it is necessary to replace the leaf springs to solve the problem. (5) If the lengths of the parallel tie rods are inconsistent and the forces on both sides are uneven, it is also a major reason for the vehicle to run deviated. At this time, it is necessary to adjust the parallel tie rods to the same length. (6) Due to a traffic accident that causes the frame to deform and the steering sleeve to tilt with the angle changed, it will also cause the vehicle to run deviated. At this time, it should be corrected. If the main beam is seriously tilted and distorted, it is necessary to replace it with a new one.
- 三轮电动三轮车打开钥匙后，转动转把时，车不启动，但车灯正常故障现象：打开钥匙后，转动转把时，车不启动，但可控制车灯。
分析检修：怀疑车内控制电动机部位异常。测量控制小盒内B+36V、U2和U4输出正常，但电动机M+、M?两端无电位差，说明控制器异常。更换控制器后电动三轮车正常。
6.The Electric Tricycle Doesn’t Start When Turning the Throttle Grip After Turning on the Key, While the Lights Are Normal **Fault Phenomenon**: After turning on the key and turning the throttle grip, the vehicle doesn’t start, but the lights can be controlled. **Analysis and Maintenance**: Suspect that the part in the vehicle that controls the motor is abnormal. Measure the B + 36V, U2 and U4 outputs in the control box and find them to be normal. However, there is no potential difference between the two ends of the motor M + and M?. This indicates that the controller is abnormal. After replacing the controller, the electric tricycle operates normally.
- 货运电动三轮车电动机不转故障现象：电动机不转
分析检修：检查电源24V正常。打开控制器，测15V电压很低，拆下控制器内稳压二极管VS1，测其正反向电阻很小，说明VS1损坏，观察VS1外形很小，说明VS1功率小，更换一只参数为15V/1W的稳压管，15V电源恢复正常。转动转把，输出电压很低且不变。检查发现转把输出引线有断路处，重新接好，故障排除。
7.The Motor of the Freight Electric Tricycle Doesn’t Rotate **Fault Phenomenon**: The motor doesn’t rotate. **Analysis and Maintenance**: Check that the 24V power supply is normal. Open the controller and measure that the 15V voltage is very low. Remove the voltage stabilizing diode VS1 in the controller and measure its forward and reverse resistances, which are found to be very small, indicating that VS1 is damaged. Observe that the appearance of VS1 is very small, indicating that the power of VS1 is small. Replace it with a voltage stabilizing diode with parameters of 15V / 1W, and the 15V power supply returns to normal. Turn the throttle grip, and the output voltage is very low and remains unchanged. Upon inspection, it is found that there is an open circuit in the output lead of the throttle grip. Reconnect it properly and the fault is eliminated.
- 货运电动三轮车电动机不转
故障现象：电动机不转分析检修：检测电源24V、15V、5V电压空载时正常，转动转把，测控制器内V1、V2栅极电压很低，焊开V2、V2栅极引线，测运放块的输出电压为14V正常。怀疑V1、V2损坏。拆下后V1、V2测试却正常。把24V电源线直接接在电动机两端，电动机依然不转，此时测得电源两端电压很低。最后检查引线，发现蓄电池线夹氧化，造成接触电阻大。电动机不转时，由于输出电流小，接触电阻造成压降小，因此测各路电压正常，而在加载时，电动机电流上升，接触电阻形成的电压降增大，致使电源端电压降低，不足以使电动机旋转。清除线夹氧化物后，故障排除。可见检查电压还应注意负载轻重不同，以免走弯路。
8.The Motor of the Freight Electric Tricycle Doesn’t Rotate **Fault Phenomenon**: The motor doesn’t rotate. **Analysis and Maintenance**: Detect that the voltages of 24V, 15V and 5V are normal under no-load conditions. When turning the throttle grip, measure that the gate voltages of V1 and V2 in the controller are very low. Solder off the gate leads of V2 and V2, and measure the output voltage of the operational amplifier block, which is 14V and normal. Suspect that V1 and V2 are damaged. However, after removing and testing them, V1 and V2 are found to be normal. Connect the 24V power line directly to the two ends of the motor, and the motor still doesn’t rotate. At this time, measure that the voltage at both ends of the power supply is very low. Finally, check the leads and find that the battery wire clips are oxidized, resulting in a large contact resistance. When the motor doesn’t rotate, because the output current is small, the voltage drop caused by the contact resistance is small, so the voltages of all circuits are measured to be normal. However, when loaded, the motor current increases, and the voltage drop formed by the contact resistance increases, causing the voltage at the power supply end to decrease and not enough to make the motor rotate. After removing the oxides on the wire clips, the fault is eliminated. It can be seen that when checking voltages, attention should also be paid to different load conditions to avoid taking detours.
- 货运电动三轮车电动机不转
故障现象：电动机不转。
分析检修：测24V、15V、5V电源正常，转动转把，输出电压在1．2～4．0V之间变化正常，但测运放块A1、A3、A4输出电压不变。经测试运放LM324坏。更换后，①脚、⑧脚、⑩脚输出电压变化正常，而电动机仍不转，拆下V1、V2测试发现已损坏，更换后故障排除。
- 9. The Motor of the Freight Electric Tricycle Doesn’t Rotate **Fault Phenomenon**: The motor doesn’t rotate. **Analysis and Maintenance**: Measure that the 24V, 15V and 5V power supplies are normal. When turning the throttle grip, the output voltage changes normally between 1.2 and 4.0V. However, measure that the output voltages of the operational amplifier blocks A1, A3 and A4 remain unchanged. After testing, it is found that the operational amplifier LM324 is broken. After replacing it, the output voltages of pins ①, ⑧ and ⑩ change normally, while the motor still doesn’t rotate. Remove and test V1 and V2 and find that they are damaged. After replacing them, the fault is eliminated.
- 货运电动三轮车电动机转不停
故障现象：电动机转不停。
分析检修：接通电源，控制器失控，电动机转不停。断开电源，打开控制器，分开检查，V1、V2正常，下部二极管VD1击穿短路。这时电源通过VD1直接通到电动机上，造成电动机转不停。更换二极管VD1后电动机正常。
10.Fault of the Motor of the Freight Electric Tricycle That Keeps Rotating **Fault Phenomenon**: The motor keeps rotating.
**Analysis and Maintenance**: When the power is connected, the controller gets out of control and the motor keeps rotating. Disconnect the power supply, open the controller and conduct separate inspections. V1 and V2 are normal, but the lower diode VD1 is broken down and short-circuited. At this time, the power supply directly reaches the motor through VD1, causing the motor to keep rotating. After replacing the diode VD1, the motor operates normally.
- 货运电动三轮车电动机转但输出力矩小，火花大
故障现象：电动机转但输出力矩小，火花大。
分析检修：测量电源及控制电路正常，判断为电动机故障。拆开电动机检查发现电刷磨损严重。抽出转子，发现换向器不均匀磨损，高处与低点差1mm多。换向器磨损不均匀使打火更加严重，输出力矩小。此故障最常见于两副电刷电动机中，而一副电刷电动机此故障少见。拆下轴承，将转子轴末端夹在转子、换向器、印镀机进行加工。转子换向器表面经过加工后，开槽，刷镀镍钨合金，获得耐磨保护层，换向器表面光洁，大大减少碳刷磨损。最后，清除碳粉、灰尘等杂物，装配好电动机，故障排除。
- 11. Fault of the Motor of the Freight Electric Tricycle That Rotates with Small Output Torque and Big Sparks **Fault Phenomenon**: The motor rotates, but the output torque is small and there are big sparks. **Analysis and Maintenance**: After measuring the power supply and control circuit and finding them to be normal, it is judged to be a motor fault. When the motor is disassembled for inspection, it is found that the carbon brushes are seriously worn. When the rotor is pulled out, it is found that the commutator is unevenly worn, with the difference between the highest and the lowest points being more than 1 mm. The uneven wear of the commutator makes the sparking more serious and results in a small output torque. This kind of fault is most commonly seen in motors with two sets of carbon brushes, while it is rare in motors with one set of carbon brushes. Remove the bearings, clamp the end of the rotor shaft in the rotor, commutator and electroplating machine for processing. After the surface of the rotor commutator is processed, grooves are cut, and nickel-tungsten alloy is brush-plated to obtain a wear-resistant protective layer, making the surface of the commutator smooth and greatly reducing the wear of carbon brushes. Finally, remove debris such as carbon powder and dust, assemble the motor properly, and the fault is eliminated.