In a construction site, a construction hoist, or called personnel and material hoist, a temporary construction elevator, construction lift, man lift or even a buck hoist is usually an important facility for purpose of increasing work productivity, reducing the risk of on-site accidents, heightening worker morale, and providing fast accessibility for paramedics, or other emergency personnel, etc.
Industrial construction hoists vary in load-bearing capacity, maximum lifting heights and lifting speeds, but each hoist features the following safeguards to prevent injury or accident:
Drive methods
Comparison of the two drive methods
| Item | By contactor | By frequency inverter |
| Impact to machinery | Huge | Small |
| Starting current | 2~7 times rated current | 1.2 times rated current |
| Speed range | None, or a fixed ratio | Above 1:100 |
| Brake | Direct brake at full speed | Brake at a low speed |
| Working process | Big shock | Stable and comfortable |
| Item | V/f, sensor-less vector control 1 | Sensor-less vector control 2 |
| Output torque at low Freq | 180% output torque at 0.5Hz | 180% output torque at 0.25Hz |
| Torque response | <10ms | |
| Protection | Short circuit, undervoltage, overvoltage, overload, phase sequence | |
| Contracting brake | Specific contracting brake param group, programmable | |
| Brake | Brake unit for energy consumption, or AFE (active front end) for energy feedback with almost no harmonic | |
Note: please select GK800 series ac drives when close-loop vector control is required for better control with higher precision
Variable speed drive selection when a couple of motors drive a hoist
GK620 is a general-purpose AC drive with V/Hz and sensor-less vector control. It’s powerful in performance, reliable in quality and optimized in structure. GK620 is widely used in various applications including air compressor, crane & lift, metal processing, mining, mills, food and beverage processing, packaging, conveyor, textile, plastics, fan & pump, etc.
