A hoist, also called a winch, is a device that is driven by human or mechanical power to complete the traction work by winding and winding the rope. It is a vertical lifting, horizontal or inclined pulling heavy-duty mechanical single lifting equipment. It is divided into manual and electric types.
The electric hoist is composed of an electric motor, a coupling, a brake, a gearbox and a drum, which are installed together on the frame. For situations where the lifting height and handling capacity are large, and the work is busy, good speed control performance is required, especially fast lowering of the hook. For sensitive materials or materials that need to be installed in place, it needs to be able to descend at a micro-moving speed.
The traditional speed regulation method is to use a wound rotor asynchronous motor and insert several sections of resistors in the rotor circuit through a collector ring and a carbon brush to control the speed by controlling the amount of resistors connected by the contactor. For example: wound rotor asynchronous motor rotor series resistor speed regulation, thyristor stator voltage regulation speed regulation and series speed regulation, etc.
With the continuous improvement of the requirements for the speed control performance of hoist equipment in industrial production, the common traditional hoist equipment speed control methods have the common shortcomings that wound rotor asynchronous motors have collector rings and carbon brushes, which require regular maintenance, and faults caused by collector rings and carbon brushes are more common, coupled with the use of a large number of relays and contactors, resulting in a large amount of on-site maintenance, and the comprehensive technical indicators of the speed control system are poor, which cannot meet the special requirements of industrial production.
The series resistor speed regulation has a jumping speed change, and is affected by impact force during acceleration and deceleration stages. The equipment is
Traditional speed regulation method: using a wound rotor asynchronous motor, through the collector ring and carbon brush in the rotor circuit in series with a number of segments of resistance, the contactor to control the amount of access resistance to control the speed. For example: winding rotor asynchronous motor rotor series resistance speed regulation, thyristor stator voltage regulation and series speed regulation, etc.
With the industrial production of winding machine equipment speed control performance requirements continue to improve, commonly used traditional winding machine equipment speed control method, the common disadvantage is that the winding rotor asynchronous motor has collector ring and brush, they require regular maintenance, caused by the collector ring and brush failure is more common, coupled with a large number of relays, the use of contactors, resulting in a large amount of on-site maintenance, speed control system failure rate is high, and speed control The comprehensive technical index of the system is poor, can not meet the special requirements of industrial production.