The power source for the battery forklift to walk and lift is the electric motor. The quality of the motor directly affects the quality of the forklift. If the motor is not properly selected, the battery forklift may have faults such as large operating noise, current exceeding the rated value, and the motor being burnt. This paper analyzes and studies the problems existing in a 0.8t battery forklift hoist motor and proposes improvement measures. 1. There is a problem with the lifting motor (1) Defect of the lifting motor itself A certain type of 0.8t forklift is limited by internal space, and its lifting motor uses a permanent magnet motor. The permanent magnet motor used for battery forklift lifting has the following deficiencies: First, the permanent magnet motor is compared with the DC compound excitation and series excitation motor (the battery forklift hydraulic pump motor usually adopts such a motor). When the load increases, the required current cannot be increased correspondingly, that is, the overload capability is poor. Second, the permanent magnet motor has a high demagnetization phenomenon under high temperature (the body temperature exceeds 85 °C), and the output power is significantly reduced after demagnetization. Third, the low voltage (below 48V) permanent magnet motor is more difficult to manufacture when the power is greater than 1 kW, the quality is difficult to guarantee, and the reliability is poor. (2) Lifting hydraulic system has a great influence on the hoisting motor The 0.8t forklift lifting hydraulic system consists of a lifting hydraulic pump, a lifting cylinder and a multi-way valve. The hydraulic system acts as a load on the hoist motor, and the following factors affect the reliability of the hoist motor: The first is the lifting hydraulic pump displacement. In the case where the system pressure is determined, the larger the lift hydraulic pump displacement, the faster the lifting speed and the greater the power demand for the lift motor. Therefore, after the hydraulic system pressure and the hoisting motor power are both determined, if the hoisting hydraulic pump with a large displacement is selected, the hoisting motor will be in an overload state. The second is the multi-way valve from the characteristics. If the multi-way valve is less than the characteristic (the combination of the multi-way valve and other original parts of the lifting hydraulic system), the pressure loss of the hydraulic system will be large, resulting in overload of the lifting motor. 2. Improvement measures (1) Improvement plan The multi-way valve application of small-tonnage battery forklifts has become a difficult problem in the whole industry. At present, various multi-way valve manufacturers have not found a good solution in this respect. Therefore, we mainly improve the life of the 0.8t battery forklift hoisting motor from the following two aspects: First, the hoisting motor selects the low-speed, high-torque DC series-excited motor with the same power as the original permanent magnet motor; the second is to reduce the lifting hydraulic pressure. Pump displacement. (2) Testing and analysis The improved permanent magnet motor has a rated power of 3k W, a rated current of 147A, and a rated speed of 2000r/min. The improved low-speed, high-torque DC series-excited motor has a rated power of 3k W, a rated current of 170A, and a rated speed of 1500r/min. After using the low-speed, high-torque DC series-excited motor, we tested the lifter and the lift hydraulic pump under different displacement conditions. The test results are shown in Table 1 and Table 2. The full load lifting current is slightly higher than the rated current of the motor, the lifting noise is slightly higher, and it is harsher. The lifting speed meets the design requirements and needs continuous improvement. According to the test, when the displacement of the lifting hydraulic pump is reduced from 10mL/r to 9mL/r, the full-load lifting current is between 128 and 135A, which is less than the rated current of the lifting motor (170A). 3. Improve the effect This type of 0.8t battery forklift implements the above improvements, and better solves the matching problem between the lifting hydraulic pump and the hoisting motor. The technical performance and reliability of the hoisting motor are improved, and the lifting noise is no longer high. The fault that the rising current exceeds the rated value and the hoisting motor is burnt. The success of this improvement has improved the quality of this type of 0.8t battery forklift. 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