Application of the hottest VEC frequency converter

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Application of VEC frequency converter on gantry

0. Introduction

Qingdao Bay Bridge (North Bridge site) is the starting point of Qingdao section of "Qingdao Lanzhou Expressway (M36)" in the national highway planning, and it is also an important part of "one road, one bridge and one tunnel" in the cross sea access Road on the East and West banks of Jiaozhou Bay in the road traffic planning and layout of our city. The construction of the bay bridge will achieve the road network planning goal of forming a "four hour economic circle" between the central cities in the peninsula urban agglomeration and a "one hour economic circle" between the central cities in the region and the counties and cities in the local city. The following is an example of the application of the V7 series frequency converter of Shenzhen vikoda in the gantry traveling part of the construction site of Qingdao Bay Bridge

1. Process requirements:

in order to improve the production efficiency, the gantry is required to have fast process requirements during lifting and discharging, that is, when the materials are hoisted or lowered, the first 3/5 travel is fast to improve the work efficiency, and the last 2/5 travel is required to be slow to accurately place and reduce the shaking of materials. The original gantry traveling motor system uses a double speed cone motor, which uses fast speed to ensure that the materials quickly reach the close place of the operation purpose, and then uses slow speed to approach the destination to ensure that they can be in place accurately

2. Shortcomings of the original control system:

2.1 the whole line is realized by relays. The line is complex, the fault handling time is long, and it is inconvenient to maintain

2.2 the speed is not adjustable and cannot meet the growing production needs

2.3 when using the cone rotating double speed belt brake motor, due to frequent start and stop, after several years of use, obvious faults have occurred, and the brake block is easy to be damaged, with a large amount of maintenance. The motor is also easy to burn out due to braking. Therefore, the transformation is proposed

3. Reconstruction plan

in order to not only improve the production efficiency, but also reduce the bubble size in the modified foam, which is smaller than the manufacturing cost, maintenance cost and workload used by electrical appliance manufacturers in the market at present, we have adopted Shenzhen vikoda v715kw frequency converter and Mitsubishi FX series PLC to carry out the modification, and use the multi-stage speed and updown function of the frequency converter to adjust the speed and improve the production efficiency. The schematic diagram is as follows:

Y0 of PLC is the slow bit, Y1 is the up frequency rising terminal, Y2 is the down frequency falling terminal, Y3 is the forward rotation signal, Y4 is the reverse rotation signal

its control process is:

when the material is hoisted, Y3 rotates forward, KM1 and km2 are closed, the electromagnetic brake is disengaged, and the gantry crane begins to move forward, and its moving speed can be adjusted by Y1 and Y2 terminals. When it is about to reach the target position, the deceleration travel switch acts, Y0 slow position is closed, and the gantry crane is switched to slow operation; When in place, Y0 and Y3 are disconnected, KM1 and km2 are disconnected, the electromagnetic brake is locked, and the gantry crane stops to unload materials

similarly, when the gantry crane puts down the material and returns, the Y4 reverse terminal is closed, KM1 and km2 are closed, and the electromagnetic holding brake is released. When the deceleration position is reached, the multi-stage speed reduction terminal Y0 is closed, and the gantry crane slows down. After reaching the parking position, Y4 and Y0 are disconnected, KM1 and km2 are disconnected, the electromagnetic holding brake is locked, and the gantry crane stops to lift the material

4vec-v7 frequency converter commissioning parameters:

according to the requirements of the on-site process of the gantry crane, The adjusted inverter parameters are: inverter operation mode f00=0

operation command source f01=2

main operation frequency setting f02=0

maximum operation frequency f03=50

acceleration time f13=10

deceleration time f14=10

parking mode f17=1

DC braking current f24= 100%

multi function input 1f34=8

multi function input 2f35=9

function input 3f36=0

multi function output terminal f39=9

the company will On March 16, a temporary meeting of Southeast University was held to consider the proposal. The frequency was set to f45=20

the comparison effect after using five vec-v7 frequency converters:

5.1 control the starting current of the motor

when the motor is directly started at the power frequency, it will produce 7 to 8 times the rated current of the motor, which will greatly increase the electrical stress of the motor winding and generate heat, thereby reducing the service life of the motor, Using V7 variable-frequency speed regulation of vikoda can start at zero speed and zero voltage. The frequency converter can drive the load to work according to v/f or vector control mode, which can fully reduce the starting current and improve the bearing capacity of the winding. The maintenance cost of the motor will be further reduced, and the service life of the motor β- There are two ways of ring opening polymerization of butyrolactone: life increases correspondingly

5.2 reduce the voltage fluctuation of the power line

when the motor starts at the power frequency, the voltage will also fluctuate greatly with the sharp increase of the current. The voltage drop will lead to the fault tripping or abnormal operation of the voltage sensitive equipment in the same power supply network, such as the sensor proximity switch and contactor, etc. will act incorrectly. After the frequency conversion speed regulation is adopted, the voltage drop can be eliminated to the greatest extent because it can be started gradually at zero frequency and zero voltage

5.3 better energy-saving effect

since the motor power is directly proportional to the product of current and voltage, Chengde zongchi will gather in mountain city in April nbsp; Describe that the power consumed by the motor directly started by power frequency in the future of Western plastic new will be much higher than the power required for variable-frequency starting; The final energy consumption is also proportional to the speed of the motor. Because the moving speed of the gantry crane cannot reach the power frequency, the power consumption is greatly reduced

5.4 reduce the loss of machinery

when the gantry crane starts through the power frequency, it will produce severe vibration to the motor or the connected mechanical parts, which will aggravate the mechanical wear and loss and reduce the service life of mechanical parts and motors; The variable frequency speed regulation can be accelerated smoothly according to the acceleration time and acceleration curve when starting at zero speed, which reduces the vibration of the mechanical part and prolongs the service life of the mechanical parts and motors

5.5 simple control part

the use of variable frequency speed regulation can optimize the process and realize speed change and change the running direction through remote control PLC programmable controller according to the gantry crane process. The control circuit is simplified and the maintenance of the electrical system is reduced

6. Conclusion:

in actual production, the system operates stably and reliably, with fast corresponding speed, which greatly improves the production efficiency. At the same time, the failure rate is also very small, which reduces the maintenance volume and cost, and has obvious economic benefits

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