With the rapid development of economy, in engineering construction, more and more large, more and more complex projects have higher requirements for lifting machinery, which put forward higher requirements for the design and manufacture of lifting machinery, many types of cantilever crane (rotary arm crane) large rated lifting weight is constantly updated.
With the shortening of product life cycle and the speeding up of crane replacement, the expectation of crane delivery time is getting higher and higher. In order to meet the diversified and personalized requirements of users, the ability of enterprises to develop new products is becoming stronger and stronger, and the development cycle of the rotary arm crane is greatly shortened. Because of the application of new technology, the manufacturing cycle and life cycle of the crane are shortened, and the replacement speed of the crane is accelerated. Diversification of production methods.
With the diversification and individuation of user demand and the requirement of product delivery time, some enterprises need to adjust production mode to meet the requirements of different users. The driving mode of cantilever crane operation mechanism can be divided into two categories: one is centralized driving, that is, one motor drives the long drive shaft to drive the driving wheels on both sides; the other is driven separately, that is, the driving wheels on both sides are driven by one motor.
Small and medium-sized bridge cranes are usually driven by a combination of brakes, reducers and motors. Universal coupling is often used in the driving device of ordinary bridge cranes with large lifting weight for easy installation and adjustment. Variable frequency speed regulation is to change the synchronous speed by changing the frequency of the stator power supply to achieve speed regulation. To make the induction motor frequency variable, it is necessary to use a frequency converter. Frequency conversion speed control equipment is to convert constant voltage and constant frequency power supply into power supply unit with variable voltage and frequency conversion.
The control mode of frequency converter is divided into two forms: open loop and closed loop control. Frequency conversion speed control electronic control equipment programmable and optional power supply into the switch, line contactor, auxiliary switch, auxiliary relay and other components.