Summary

 

This article focuses on the use of easy-drive GT200 series 160KW inverters to transform the outdated, backward and energy-consuming hoist system on a tunnel construction site in Baoji, Shaanxi.

 

Keywords: winch, frequency converter, electric control system, PLC, touch screen

 

I. Introduction

 

With the continuous improvement of the requirements for the speed regulation performance of the lifting equipment in the industrial and mining production, the traditional equipment speed regulation method is the winding rotor asynchronous motor rotor series resistance speed regulation. The disadvantage is that the wound rotor asynchronous motor has a slip ring and brushes, and they need Regular maintenance often causes failures due to slip rings and brushes, coupled with the use of a large number of relays and contactors, resulting in a large amount of on-site maintenance, a high failure rate of the speed control system, and a relatively high comprehensive technical index of the speed control system Poor, it can no longer meet the special requirements of industrial production. This article introduces the use of easy drive GT200 series 160kW inverter to transform the hoist system.

 

2. Disadvantages of the original lifting system

 

The speed regulation of the motor rotor series resistance speed regulation system belongs to stepped speed regulation, open loop control, small speed regulation range, low speed regulation accuracy, and crawling speed is not easy to control, especially when heavy objects are lowered, dynamic braking and rotor series resistance are required It is not easy for the driver to control, and the safety performance is poor. When decelerating and lowering heavy objects, putting in dynamic braking not only consumes the external DC power, but also consumes the regenerative power from the motor on the resistance of the rotor connected in series, wasting a lot of power, and the operation and maintenance is large. costly.

 

Third, the advantages of easy drive inverter after transformation

 

　　 After AC variable frequency speed regulation technology is applied to hoist equipment, compared with the traditional wound asynchronous motor rotor string resistance speed regulation system widely used in the market, it can bring the following significant economic benefits and safety and reliability:

 

　　 (1) The frequency conversion hoist runs smoothly, starts and brakes smoothly, the vibration and impact of the whole machine are obviously reduced during acceleration and deceleration during operation, the safety is improved, and the life of the mechanical part of the crane is prolonged.

 

　　 (2) The mechanical brake works when the motor is at low speed, and the braking is completed by the electric brake, so the life of the brake pads of the mechanical brake is greatly extended, and the maintenance cost is reduced.

 

　　(3) Short-circuit the wound rotor part to avoid the motor damage or failure to start due to poor contact caused by the slip ring and brush wear or corrosion.

 

　　 (4) The number of AC contactors is greatly reduced, and the main circuit of the motor realizes non-contact control, which avoids the frequent action of the contactor and the motor damage caused by the burning of the contactor.

 

　　(5) The AC frequency conversion speed regulation system can flexibly adjust the speed and acceleration and deceleration time of each gear according to the site conditions, making the frequency conversion crane flexible in operation and good on-site adaptability.

 

　　(6) The AC variable frequency control system is a high-efficiency speed control system with high operating efficiency and low heat loss, so it saves a lot of electricity compared to the old speed control system.

 

　　(7) The inverter has perfect protection, monitoring and self-diagnosis functions. If combined with PLC control, it can greatly improve the reliability of the inverter crane electronic control system.

 

Four, scene pictures

5. Summary 　　

 

　　 The wide application of AC variable frequency speed regulation technology in the industry provides a new solution for AC asynchronous motor drive and speed regulation. It has high-performance speed regulation indicators. It can use a squirrel cage asynchronous motor with simple structure, reliable work and convenient maintenance, and is efficient and energy-saving. Its peripheral control circuit is simple, maintenance workload is reduced, protection monitoring functions are complete, and operation reliability is relatively high. The traditional AC speed regulation system has been greatly improved. Therefore, the use of AC frequency conversion speed regulation is the mainstream of the development of crane AC speed regulation technology.