Defects of the hottest pump controlled electro-hyd

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Defects of pump controlled electro-hydraulic grab

electro-hydraulic grab is a pick-up device under the crane, which is used for loading and unloading various goods. The working condition (working system) is continuous and frequent work for a period of time

there are two kinds of electro-hydraulic grab, one is pump controlled grab, the other is valve controlled grab

the opening and closing of the pump controlled electro-hydraulic grab is to control the closing and opening of the grab through the forward and reverse rotation of the hydraulic pump. The forward and reverse rotation of the hydraulic pump is driven by the forward and reverse rotation of the motor, and the forward and reverse rotation is very frequent. The motor is constantly and frequently started, especially like the electro-hydraulic multi flap grab used in waste incineration plants. During feeding, the grab is opened and stopped several times before the grab is fully opened, Because of a one-time fight, the dragging garbage will be discharged too quickly, which will block the funnel

the opening and closing of the valve controlled electro-hydraulic grab is to control the closing and opening of the grab through the reversing valve in the hydraulic pump station. When the grab is working, the motor and the hydraulic pump always rotate in the same direction, and the motor only needs to be started once. No matter how frequently it works, it is only to control the reversing valve to change the direction

therefore, compared with valve controlled electro-hydraulic grab, pump controlled electro-hydraulic grab has the following disadvantages:

1 When starting the motor, it belongs to on load starting. The starting current of the motor is large, and it starts frequently, which is easy to burn electrical components

2. The motor starts frequently with load, which is easy to break and has short service life

3. The motor is started under load to fulfill the standard. Its starting current is usually more than 6 times of the normal working current, leaving infinite hidden dangers. Due to its frequent positive and negative rotation, it is equivalent to that the power system is in a high load state for a long time, causing a load greater than its rated power to the power supply system, and the power consumption is also large

4. Frequent forward and reverse rotation of the motor also has a huge impact on the motor itself, which is easy to cause the positioning screw hole of the cast iron motor housing to be broken and cannot be used. Commonly used motor housings are cast iron, unless customized

5. The hydraulic pump frequently rotates forward and reverses, and the hydraulic system has great impact. The service life of mu10 pump is short, and the oil pipe is easy to burst


adopt energy-saving pump controlled electro-hydraulic grab. For details, please see the eight advantages of energy-saving electro-hydraulic grab and how to choose electro-hydraulic grab written by Shanghai grubo Machinery Co., Ltd


1 Jiangsu Zhangjiagang POSCO Stainless Steel Co., Ltd. used to use pump controlled grab. Because of the high failure rate and the frequent failure of the motor, it not only costs high maintenance costs, but also affects production. After demonstration, it was decided to transform the pump control into valve control, and the quantitative pump into variable pump. It requires zero load startup, variable output, small overflow oil volume, small temperature rise, and oil temperature operation at 60oC. The project is entrusted to Shanghai grubo Machinery Co., Ltd

2. Shanghai grubo Machinery Co., Ltd. manufactured two 450 yuan single early electro-hydraulic multi flap scrap grab for Nantong port group. The hydraulic pump station adopts valve control, and the hydraulic system adopts energy-saving. Nantong Port Group has used it for nearly a year without any failure. Recently, Shanghai Gruber won the bidding for the procurement of three 40t electro-hydraulic double flap grab of Fujian Jiangyin International Container Terminal Co., Ltd. with its leading technical advantages. (end)

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