The electric control system is the "nerve center" of the concrete pump truck, which is an important guarantee for the normal operation of the pump truck. The composition of the system is complex and the fault location is relatively difficult. In order to minimize the loss of production, it is necessary to realize the rapid detection and location of the electrical system fault of the concrete pump truck. The maintenance ideas are: familiar with the working principle of the pump truck and the electrical logic relationship of various actions, in accordance with the correct fault detection process and application. The fault detection means detects, continuously narrows the fault range, and finally finds the fault point to be eliminated.
I. SY5392-40 Pumping car transfer case position proximity switch fault handling: Sany Heavy Industry's SY5392-40 pump truck adopts Siemens S7-200 series PLC control system, which consists of one CPU224 and two EM223 expansion modules. .
1. Fault phenomenon and fault analysis: After the pump truck arrives at the scene, after the transfer box is switched from the driving position to the pumping position, it is found that the horn sounds alarm and the vehicle hydraulic system does not work.
After checking the pump truck, the pump truck rental found that when the transfer box was switched to the driving position, the system did not alarm and the work was normal, so the fault detection of the horn sounding was caused by the chassis of the car. Check the electrical system drawings and find that when switching to the driving position, the EM223(1)4# indicator lights up, and when switching to the pumping position, the EM223(2)5# indicator does not light, so it is suspected that the SQ2 proximity switch is damaged. Using a multimeter to measure I2.5, it is found that there is no input signal. Short-circuit the 40# line and I2.5 at both ends with a test lead. After the alarm is released, it can work. Check that the mechanical part of the transfer case is in the pumping position and that the SQ2 proximity switch is indeed damaged.
2. Pump car rental troubleshooting: Since there is no proximity switch spare parts on site, the temporary short circuit method is used to maintain production. After the I2.5 and 40# lines are shorted by the temporary line, the pump truck works normally, and the proximity switch is replaced after the end of production. .
Second, SY5392-40 pump truck boom without control failure maintenance
1. Fault phenomenon and fault analysis: The pump truck suddenly has no control failure during the work, no response is caused by remote control or manual control. Some electrical schematics refer to Figure 1. According to the above phenomenon combined with the analysis of the hydraulic system principle, it may be that the bypass valve DT8 or the boom valve DT26 does not operate, so that the entire boom hydraulic system has no pressure. Check the Q2.7 and Q3.5 terminals of the expansion modules Em223(1) and Em223(2) with a multimeter for signal output. Check the DT8 and DT26 wiring sockets again and find that there is 24VD voltage on DT8, but there is no 24VDC voltage on DT26. Check again that there is a disconnection between 24VDC(38)# line and DT26, and no breakpoint can be found. May be inside the cable.
2. Pump rental treatment: After analyzing the principle of electrical system and the principle of hydraulic system, it is found that the DT8 bypass valve and the DT26 boom valve must work at the same time to ensure the normal operation of the boom system and the position of the two solenoid valves. Very close, so the transfer method is feasible. After the Q2.7 end A point lead on the DT8 bypass valve (dashed line in Figure 1) to the break point B of the 38# line on the DT26 boom valve, it works normally.
Third, South Korea Daewoo 36m pump car remote control failure repair: South Korea Daewoo 36m pump truck is actually produced by the German Putzmeister company, but more than the Putzmeister 36m cloth truck mechanical manual throttle control.
1. Fault phenomenon and analysis When the pump truck is working, it suddenly finds that the electric displacement knob S54 on the wired remote control is out of order, the system can only be pumped with small displacement, and the schematic diagram of the system is shown in Figure 2. The mechanical manual throttle is controlled at a high position, and the pumping displacement is also not significantly increased. After inspection, it was found that 4F119 insurance was blown, and other functions were normal after replacement. When the electric displacement knob S54 on the remote controller is operated, the 4F119 fuse is blown again, and the displacement remains unchanged.
2. Pump car rental troubleshooting According to the system schematic check, when the S54 button is operated to increase the displacement position, the 9K48 relay contact of the increased displacement should be closed, and the reduced 9K49 relay contact is not closed. Check the S54's increased displacement position with a multimeter and the contact action is normal, while the reduced position contact is always closed, causing the 9K49 to pull in for a long time, causing the displacement control valve 4M49 to always reverse to the minimum end, the motor is blocked, current Rapid increase, the 4F119 insurance is blown, and the displacement control valve is always at the minimum displacement position. The solution is to replace the S54 reduction position contact assembly.
Fourth, the treatment of Shi Weiying KVM36 pump car remote control failure
1. Fault phenomenon and fault analysis: When a Shiweiying KVM36 pump truck of a company is working, suddenly most of the control buttons on the wired remote control fail, the red light on the remote control keeps flashing, and the control activation button cannot activate the remote control normally. Only the horn function, the total control panel - V31 and -V51 power indicator lights, the operator suspected that the wired remote control is damaged.
The stability and reliability of Shiweiying pump trucks are extremely high in use, but the electrical system still uses relay control. This kind of system is relatively complicated, the circuit diagram identification is difficult, and the maintenance is difficult. From the perspective of the fault surface phenomenon, it is very similar to the remote control damage, but when checking the remote control, it is found that the remote control actually uses an integrated circuit, and each loop has no fault, and then according to the circuit check, the condition that affects the activation of the remote controller is - The K66 relay must be closed and held. Otherwise, the -K54 controller has no output, and the -K52 relay does not pick up, causing the remote control to fail to activate.
Causes that the -K66 relay does not pick up:
- Any one of the K113, -K114, -K117, and -K121 relay malfunctions or poor contact at the normally closed point.
The 1 and 2 pairs of contacts on the S8 self-reset switch on the remote control are not in good contact or closed.
The 33, 34 pairs of contacts of the -S1 selector switch on the rear control panel and the contacts of the 43 and 44 pairs are not in good contact or closed, or the -F62 is disconnected.
The 2, 3 pairs of contacts of the S6 selector switch are poorly connected or not closed.
2. Pump rental http://fault check and treatment: analysis of the above reasons, the most likely cause of the remote control can not be activated is -K66's holding contacts have no retention, check -K113, -K114, - The normally closed contacts of K117 and -K121 are normal. When the -S1 selector switch of the rear control panel is checked, it is found that the 33, 34 pairs and 43 and 44 pairs of the contact opening and closing body and the -S1 body are loosened. The above 2 pairs of contacts are seriously in poor contact.
Therefore, when the 1 and 2 pairs of contacts of S8 are closed, the -K66 coil cannot be energized and cannot be attracted. When the 2 and 3 pairs of contacts of the S6 switch are closed, although the -K66 coil is electrically attracted, due to - The K66's holding contact has no power and cannot be held. Therefore, the -K66 still does not fit properly. After the screw that loosens the contact opening and closing body of -S1 is tightened, the test operation is normal.
When repairing the electrical system failure of a concrete pump truck, the key is to be familiar with the principles of the electrical system, as well as to understand some of the principles of the hydraulic system of the pump truck. If you fully understand the working principle of the hydraulic system of the pump truck, you will get twice the result with half the effort when dealing with electrical faults.
Jinan Pump Car Rental Co., Ltd. is located in the beautiful city of Jinan City. It is a professional construction machinery enterprise with more than ten years of development experience, integrating R&D, manufacturing, sales and installation. The company has a large number of strong technical and experienced business. Skilled and talented people. The company implements the strategy of developing science and technology enterprises, focusing on the industry leading level, and has been adhering to the business tenet of “Quality First, Customer Supreme, Pioneering and Innovative, Keeping Improvingâ€. The company not only has domestic first-class paving equipment, but also has set up a training. The professional construction team is ready to provide safe and reliable quality services for the construction of the project. Honesty and trustworthiness are our eternal creed and commitment to our customers. The company has developed a set of scientific and effective rules and regulations and set up special personnel to monitor and implement. Customer satisfaction is an important indicator for assessing employee performance. More than a thousand kinds of bridges.
The company constantly improves its organizational structure, adjusts its strategic deployment, formulates medium and long-term development strategies, and strives to become a first-class innovative enterprise with “first-class industry, first-class products and first-class serviceâ€. The company's business development is aimed at market demand. We always regard our customers as our partners. We are committed to providing high-quality and low-cost services to the market, and we can carry out new business according to the needs of users at any time.
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