Introduction
The vibratory hammer technology began in the 1920s and 1930s. The principle is that the relative motion of the eccentric gears produces up and down vibrations, so that the objects being used are separated from the surrounding soil layers, reducing the frictional resistance and achieving the purpose of sinking and pulling. The current vibratory pile hammers are divided into two categories: one is a rotary type excited vibrator, and the other type is a reciprocating type vibrator. The exciter drive device is an electric motor, which is an electric vibration pile hammer. If the exciter drive device is a hydraulic motor, it is a hydraulic vibration pile hammer. Vibratory pile hammer has been widely used in the construction of industrial and civil buildings, ports, docks, bridges, etc. as a development of vibrating machinery. It has high piling efficiency, low cost, pile head is not easy to be damaged, piles Small deformation and other advantages.
In use, traditional vibration pile hammer can not change vibration frequency and eccentric torque according to different working conditions and soil quality, making its use has been greatly limited. Even if individual vibration pile hammers realize frequency conversion and torque change, it also changes the eccentric torque due to changing the vibration frequency or manually adjusting the relative angle of the eccentric block, which makes the frequency conversion or torque-changing process time-consuming and difficult. Can not meet the requirements of modern complex construction site, but the inverter can meet this use requirements.
Principle of frequency converter
The conventional frequency conversion or torque change of the vibratory pile hammer is achieved by replacing the drive pulley to change the vibration frequency or manually adjusting the relative angle of the eccentric block to change the eccentric torque, which not only takes time and labor, but also cannot meet the requirements of modern complex construction sites. Nowadays, no matter what kind of machinery is driven by an electric motor, the vibration pile hammer is also the same. The electric vibratory pile hammer is driven by the motor exciter. Using the frequency converter to control the speed or torque of the motor can easily realize the variable frequency and torque of the vibratory pile hammer, and thus can also meet the vibration pile hammer in different working conditions. Use under.
Pu Chuan PI9230 series inverter is a new high-performance current vector inverter launched by Pu Chuan Technology based on the latest theory and technical results of motor operation and control. Through the decoupling control of the motor flux current and torque current, the rapid response and accurate control of the torque can be achieved, and a wide range of variable speed operation and torque control can be performed with high accuracy; it can be widely used in metallurgy, chemical industry, It is the speed control of many equipments in many industries, including textile, electric power, construction and so on.
The frequency converter has obvious advantages in the use of vibration pile hammers:
1: Because of the application of the inverter, the impact on the power grid is reduced, especially in the mountainous areas where the transformer capacity is insufficient or where the line is too long;
2: According to different working conditions and soil quality, the vibration frequency and control torque can be adjusted as needed;
3: Reduce the impact of the start-up process on mechanical structures such as motors and actuators to extend the life of the equipment;
4: The excellent wave-by-wave current limiting function of the PI9230 frequency converter has greatly reduced the frequent overcurrent protection caused by transient current surges.
Field case
1, on-site introduction
The site is the Guanmenshan Reservoir Bridge in Yongchuan District of Chongqing City. The project requires a bridge across the reservoir, and the vibratory hammer is used to drive the steel pipe into the riverbed during construction.
2. Application of Universal Transmission PI9230 Inverter
1) On-site situation: The vibratory hammer motor is a 90W six-pole three-phase asynchronous motor; before this site used the "De XX", "People XX" and other brand inverters, the 110KW universal type used for power. However, these two frequency converters are not capable of working conditions in the field, or they cannot be started at all, or they can be started occasionally but most of the time cannot be started. The best situation is also very hard to start but with steel pipe vibration protection. According to the on-site situation study, we decided to use PI 9230 110G3 inverter.
2) Commissioning process: the wiring is completed, the inspection is correct, the on-site voltage is 430V high, but it is understood that the transformer capacity is only 160KVA, it is estimated that the load voltage will decrease. First of all, the motor control mode adopts V/F mode, external potentiometer speed regulation and terminal control are set. The motor parameters are correctly input, and other parameters are temporarily not adjusted. The vibratory hammer does not clamp the steel pipe and suspends the air-to-air vibration. When the inverter is started, the frequency rises to about 8HZ. There is a short-term drop. It is the excellent wave-by-wave current limiting function of the PI9200. After that, it rises to 50Hz to complete the startup. In view of this situation, it was decided to use a non-inductive vector control method. First, the motor was subjected to self-learning of the static parameters. After the completion, the inverter was started. The inverter smoothly reached 50HZ within the default time of 30 seconds and operated for about 10 minutes. The current and voltage were monitored and the input voltage was monitored. Down to 390V, motor operating current 120A, everything is normal; shutdown, vibration hammer clamp steel pipe according to the normal production process work, start the inverter until after the completion of a pipe, everything is normal, monitor the current between 120-168A with the depth of the pipe gradually Increased, three-phase balance; two steel pipes were fired one after another in normal operation, everything was normal and commissioning was completed.
3) parameter settings
4) Commissioning note: As the use of non-inductive vector control, the motor must be self-learning parameters, the site of the motor and the load off the more difficult, so choose the motor static parameters self-learning;
3, maintenance: As the scene is outdoors, we must pay attention to rain and lightning, the inverter must be grounded reliably;
to sum up
Through the above-mentioned on-the-spot application, the PI9230 frequency converter has excellent motor parameter self-learning, low-frequency torque and wave-by-wave current limiting function, especially high-performance current vector control, fully qualified.
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