Frequency inverter use in continuous conveyor
Project Overview and Design Plan
Yunnan Xiaolongtan Mining Bureau is a state-owned coal production enterprise. It is one of the key mining areas of Yunnan-Guizhou Coal Base, a large coal base approved by the state. It is an important energy production base in Yunnan Province. It mainly produces lignite. It has two open-pit coal mines, Xiaolongtan and Buzhaoba, and mechanical repair and construction units. The Mining Bureau has a coal-based and multi-industry business development pattern. In addition to the coal industry, it also has mechanical repair, construction, processing, service industries, etc., and has a strong development momentum. The current five-phase expansion project is a key construction project of Yunnan Province's "Double Hundred" project. It was officially started in March 2008. After completion, the coal production will reach 14.9 million tons/year.
The main motor power of the 502 belt conveyor of the new stripping system of the Bunaoba of the Xiaolongtan Mining Bureau of Yunnan Province is 2x800kW. In order to ensure safe production and reduce the impact on the equipment, the Mining Bureau, together with the design, mechanical repair and other parties, decided to use a high-voltage inverter drive; and in order to cope with the large errors of the mechanical part, the inverter can be used to facilitate speed regulation, and a one-to-one, dual-machine synchronization method is adopted.
Working principle and characteristics of system tape machine
The belt conveyor drives the drum and pulls the belt by friction. The belt drives the object to move on the supporting roller through tension deformation and friction. The belt is an elastic energy storage material. It stores a lot of potential energy when the belt conveyor stops and runs. This determines that the belt conveyor should be started in a soft start mode. Most domestic coal mines use hydraulic couplings to achieve soft starting of belt conveyors. When starting, the mechanical efficiency of the hydraulic coupling is adjusted to zero so that the motor starts without load. When the hydraulic coupling is used to soft-start the belt conveyor, due to the narrow speed regulation range, short start-up time at low speed and large loading force, it is difficult to truly solve the distribution and synchronization problems of load power and elastic potential energy power of the belt when the front and rear double machines drive the same belt. It is easy to cause belt breakage and aging, and the belt strength is required to be high. In addition, the long-term operation of the hydraulic coupling will cause the internal oil temperature to rise, metal parts to wear, leak and reduce efficiency, which will not only increase the difficulty and cost of maintenance, but also pollute the environment.
Implementation
The dual-machine communication processing system coordinates and controls the master and slave inverter systems, and they communicate and transmit information to each other. The DCS system sends the operating frequency to the communication system, and the communication system transmits the given speed to the host, which is then transmitted to the slave by the host. When the host has a minor fault, the slave will follow the host and take corresponding measures in real time. Similarly, when the slave has a minor fault, the host will follow the host and take corresponding measures in real time. At the same time, with the help of the dual-motor power detection and processing system, the master and slave motors are automatically adjusted to run synchronously in real time, truly realizing the synchronous operation of the master and slave speeds.
Inverter selection and main circuit description:
The rated power of the inverter is 850KW, the rated voltage is 6KV, and the rated current is 100A; the quantity is 2 units.
The main circuit of the inverter is as follows:
1）. Each inverter contains a full set of QS1, QS2, KM1, KM2
2）. QS is a single-pole isolating switch and KM is a vacuum contactor.
3）. When KM is in the closed state, QS is mechanically locked and cannot be operated.
4）. KM is controlled by the DCS system to close, and the closed state is electrically maintained, and its coil has the ability to be energized for a long time.
Power saving rate and investment return analysis
The main motor power of the 502 belt conveyor of the new stripping system of the Buzhaoba of Xiaolongtan Mineral Bureau is 2x800kW, and the speed is switched by AC contactor. Due to the large power, the impact current is large when starting and shifting, and the medium and high speed operation is not stable. A large amount of electric energy is consumed in the rotor resistance, resulting in a huge waste of energy. At the same time, the operating environment of the workers is also extremely bad, and it is urgently needed to be transformedSince the frequency converter has the advantages of soft start, smooth speed regulation in a large range, and significant energy saving effect, our mine has made many investigations and decided to use the AMB-HVI high-voltage series frequency converter produced by Shenzhen Anbangxin Electronics Co., Ltd. to transform the system. After several months of operation, it has been proved that the effect of the transformation is relatively ideal.
