Recently, it is known from the market feedback that the battery forklift often has a phenomenon that the contactor contacts burn out and frequently change the lifting contactor during use, which brings great use to the user. trouble. HP350 stepless lifting speed control system 1. Lifting accelerator 2. Lifting switch 3. Lifting speed controller 4. Lifting motor 5. Battery pack 6. Contactor coil Sheet Metal Fabrication,Ss Steel Plate,Metal Chequered Plate,Patterned Plate Sheet Metal Suzhou Gold ant Precision Sheet Metal Co.,Ltd , https://www.jmycutting.com
The reason for the analysis is as follows: The gantry is the working device of the forklift, controlled by the hoisting motor, and the hoisting motor is controlled by the hoisting contactor in the chopper. During the stacking process of the forklift, the lifting, forward tilting, backward tilting and side shifting of the cargo are controlled by the lifting motor. These operations are short in time, high in frequency and large in power consumption. The hoisting motor is the largest electric motor in the battery forklift. The rated working current of the hoisting motor of the 1~1.5 t three-point battery forklift produced by our factory is 172.8 A, and the maximum working current is more than 250 A. At the moment when the contacts are turned on and off, a large current of 250 A or more will generate a strong arc, and the instantaneous heat generated is quite large, which will naturally ablate the contacts, so that the contacts will be burned out repeatedly, resulting in burnout of the contacts. The working device of the forklift does not work.
The above-mentioned problems can be solved in essence by adopting the popular lifting speed control technology at home and abroad. The lifting speed control technology mainly includes two types of stepless lifting speed control system and stepped lifting speed control system. Among them, the stepless lifting speed control system can significantly save energy and extend the use time of the forklift after each charge. The current application is relatively wide and the technology is mature. The HP350 type stepless lifting speed control system produced by ZAPI Company has the composition and working principle as shown in the drawing. The system is mainly composed of a hoisting speed controller, a hoisting motor, a hoisting switch, a hoisting accelerator and a lifting contactor.
7. Current sensor 8. Contactor contact 9. Fuse 10. Ignition switch working principle: After closing the ignition switch, the contactor TG2 coil is charged, the normally open contact of TG2 is closed, and the lifting speed controller is charged. The power MOS tube in the hoisting speed controller is in the off state, and the hoisting motor does not work. When the lifting handle is operated, the lifting switch is closed, and the control information channel of the power MOS tube is turned on. At this time, the power MOS tube is in an on state, the current passes through the fuse FU2, the contact of the contactor TG2, and the lifting speed is adjusted. The current sensor SH in the controller, the lifting motor M2, the power MOS tube, and finally the loop to the negative pole of the battery pack, the lifting motor M2 starts to work; and if the lifting handle is moved a large amount, the lifting accelerator is inside The stronger the control signal transmitted by the Hall element sensor to the hoisting chopper, the stronger the conduction capability of the power MOS tube in the chopper, the higher the speed of the hoisting motor M2, the higher the hoist pump flow, the gantry Work speed is increased.
In addition, the stepless lifting speed control system can also meet some requirements of the user for tilting, side shifting and the like. If the user needs to tilt and move the working device at a specific speed, it is only necessary to install a switch and set parameters under the corresponding valve stem to realize speed control such as tilting and side shifting, without adding any components.
In summary, the stepless lifting speed control system has the following advantages compared with the contactor control:
(1) Replace the contactor control with the lifting speed control system, realize the non-contact speed regulation, no component ablation phenomenon, the forklift has a long service life, the maintenance is simple, and the reliability of the whole machine is greatly improved.
(2) Save energy and extend the use time of the forklift after each charge.
(3) According to the user's requirements, the speed control parameters can be set to achieve personalized operation.
(4) According to the user's requirements, the common pump split can be realized, and the steering pump and the steering motor can be removed, which saves cost and saves space.
(5) Application of digital quantity control, high control precision and stable operation.
(6) The control circuit of the MOS tube is simple, the reliability is high, the switching characteristics are good; the tube pressure drop is small, the internal consumption is small, energy is saved; the control frequency is high, the control characteristics are good, and there is no noise.
Battery forklift changed to stepless lifting speed control system