Application of Delta inverter on bridge crane
Bridge cranes are bridge-type cranes that work on elevated rails. They are commonly known as cranes and are widely used. In indoor and outdoor warehouses, factories, docks and open storage yards. Generally, the overhead crane is generally composed of a lifting trolley, a working structure of the bridge, and a metal structure of the bridge. The lifting trolley is composed of three parts: the lifting organization, the trolley working organization and the small frame. The driving method of the electric working organization of the crane can be divided into two categories: one is the centralized driving, that is, one motor drives the long drive shaft to drive the automatic wheels on both sides; the other is the independent drive, that is, the automatic on both sides. The wheels are each driven by a motor. Small and medium-sized bridge cranes use the "three-in-one" driving method in which the brakes, reducer and electric motor are combined. The general bridge crane with large lifting weight is convenient for equipment and adjustment, and the driving equipment often adopts universal joint. The electric work organization consists of three substantially independent drag systems. 1 cart drag system: drag the entire crane along the workshop to do "horizontal" movement (subject to the operator's sitting direction). 2 car drag system: drag hooks and heavy objects along the bridge to do "longitudinal" movement. 3 Hook drag system: Drag heavy objects for lifting up or down. Related to improving the organization control, the crane crane has relatively low control requirements for the inverter in the dragging of the cart and the dragging of the cart. Therefore, this paper focuses on the application of the Delta VE series inverter in improving the organization and control. Improve the organization's work with a large inertia, the characteristics of the four-quadrant work, compared with other transmission machinery, the inverter has more stringent safety and functional requirements. Delta Inverter is a frequency converter specially designed for crane load. It has the following features: 1 It has full vector control. At a low frequency of 1 Hz, even with no speed reaction, a starting torque of 150% extra torque can be supplied. 2 four quadrant work. The brake unit can be configured to work in four quadrants and respond dynamically. 3 constant torque characteristics. Constant torque characteristics in the full speed range. VE frequency converter is used to improve the organization's operation plan. In order to ensure the planning conditions, the project conducts practical tests on the suitability of Delta's VE series inverter crane engineering. The test site is a factory specializing in the production of lifting equipment in Zhuzhou. Test configuration: motor type is YZR200L-8 (winding motor), power 15Kw, additional digital input voltage 380V, additional input current 34.6A, motor pole number 8 pole, additional frequency 50HZ, additional speed 712rpm, no encoder. The brake brake adopts the solenoid valve method and is controlled by a 3-phase 380V power supply. Taking into account the possibility of overload work in the future, as well as the stability of long-term work, Delta's VFD220V43A-2 inverter is used for testing. 2.1 Main circuit planning
Because Delta's inverter power is greater than 11KW type without built-in brake unit, it is equipped with one external recommended brake unit VFDB4030. The standard type of brake resistor is 4800W/27.2 ohm. Considering the braking function and the heat dissipation function of the resistor when the weather is hot, the selection principle of the brake resistor standard has two aspects: the equivalent resistance value is kept at the recommended smaller resistance value. The power is selected to be about 2 times the recommended power. Because there is a standard spot of BR1K5W040 (1500W/40 ohms) on hand, 12 resistors of BR1K5W040 standard are selected, connected by series and parallel, the equivalent resistance is 30 ohms, and the equivalent power is 18KW. The schematic diagram of the practice connection is shown in Figure 2.