1. Introduction to General Construction Hoists

As a vertical transportation device for delivering personnel and fragmented materials in high-rise building construction, hoists have been widely used. In China, there are dozens of varieties produced, over 90%of which are in the range of1to2tons. However, they face similar issues as tower cranes. The main reasons include:

(1)Control System

The control system is a critical part of construction hoists, determining the overall performance of the equipment. Traditional hoists use contactor control, resulting in single-speed operation with significant start-stop shocks that severely damage structures and mechanisms, as well as electrical components. The operating speed is relatively low, usually around 34-38m/min, affecting both construction speed and efficiency. Simply increasing the speed can lead to excessive acceleration, causing greater wear on gears, racks, and brake discs, reducing operational reliability.

(2)Starting and Braking Systems

Traditional hoists typically use direct starting or star-delta voltage reduction starting, causing significant impact that damages motors and electrical components. Materials inside the hoist can easily fall, especially when passengers are present, posing serious safety risks. Traditional braking systems rely on mechanical clamping brakes, which, when stopping suddenly from high speeds, cause structural damage due to inertia, potentially leading to material falls and further safety hazards.

(3)Leveling System

Traditional hoists lack a creep process during deceleration to leveling, directly transitioning from operating speed to zero speed. Level selection is manually controlled by operators, often requiring several adjustments for accurate stops, reducing efficiency and increasing wear on drive and control systems, thus shortening their lifespan and wasting time.

2.Introduction to Variable Frequency Construction Hoists:

Variable frequency construction hoists feature the following characteristics:

Reliability

Comprehensive reliability design solutions such as redundancy design and derating design are adopted, using industrial-grade or military-grade components; professional manufacturing platforms ensure the overall reliability of the equipment.

Soft Start

Compared to fixed-frequency starting methods, variable frequency drives reduce vibrations and structural impacts, saving maintenance costs and ensuring stable operation.

High Starting Torque

Utilizing high-performance flux vector control modes provides stable high output torque at low frequencies.

Safety

Equipped with zero servo function, enabling full torque output at zero speed, preventing load slippage even if the brake fails, ensuring system safety.

Modern AC variable frequency speed control technology applied to hoist power transmission systems ensures smooth operation, improves efficiency, reduces overload work, eliminates start-stop shocks, lowers electrical maintenance, reduces energy consumption, and enhances power factor. It also includes protections against overcurrent, overvoltage, undervoltage, phase loss, overheating, overload, overspeed, I/O faults, motor faults, etc. Variable frequency speed control offers notable advantages:Significant Features of Variable Frequency Speed Control:

(1)EfficiencyOperating speeds can reach 60to70m/min, doubling traditional speeds (34m/min). Infinitely variable speed control effectively mitigates transmission impacts, extending the life of gears, wheels, bearings, and racks. Due to its current-limiting capability, it reduces the impact on the grid during motor startup, enhancing cable current capacity without increasing cable size, thereby saving costs.

The variable frequency speed control system features comprehensive safety protections like under-voltage, over-voltage, over-torque, and over-current protections, ensuring system reliability and safety. Zero-speed braking minimizes relative friction, theoretically offering infinite service life.

It adopts advanced leveling control systems, replacing high-failure relay systems, improving accuracy and efficiency.

(2)Economic EfficiencyDespite higher speeds and power, energy consumption decreases by 50%compared to traditional models, as motors do not require power during descent. Maintenance costs are reduced, with fewer gear replacements and extended rack lifespans.

Changsha Sunye Electric Co., Ltd. (established in 2010) and Shenzhen Sunye Electric Co., Ltd. (established in 2002) are national high-tech enterprises specializing in R&D, manufacturing, and sales of inverters, industry-specific integrated machines, servo drives, and new energy products.

Sunye Electric owns independent intellectual property rights, with products certified by national authorities and multiple software copyrights and IP certificates. Significant investment is made annually in new technologies and product development, with numerous patents and software copyrights approved. The company possesses core platform technologies such as construction hoist drivers, high-performance vector inverters, servos, and permanent magnet synchronous motor controls. Medium- and low-voltage inverters and servo drives are widely used in industries such as lifting, stone processing, HVAC, machine tools, metal products, wire and cable, plastics, printing and packaging, textile and chemical fibers, building materials, metallurgy, coal mining, municipal services, and automotive manufacturing. Guided by the philosophy of “Innovation, Technology, Strength,” driven by the corporate spirit of “Unity, Progress, Pragmatism, Innovation,” and adhering to the business principle of “Sincerity and Excellence, Mutual Benefit and Coexistence,” the company aims to provide industry-leading products through comprehensive quality management, continuous improvement, and pursuit of zero defects.

Address: Sunye Electric Industrial Park, No. 669 Xinsheng Road, High-Tech Zone, Changsha City

Tel/Fax:0731-89932666 0731-89932688

Business Phone:400-0755-731