Construction hoists are commonly used construction machinery for carrying personnel and materials, playing a vital role in the safe and efficient vertical transportation of personnel and materials.
Currently, the mainstream drive solution for construction hoists is the ordinary frequency converter + braking resistor solution. When the construction hoist using this solution is lowered, it will pass through the braking resistor, which will generate heat, seriously affecting the comfort inside the cage, and the resistor consumption will cause a great waste of electricity.
Taking the application of INVT GD300-29 series energy feedback frequency converters in construction hoists as an example, this article details how INVT's integrated energy feedback machine solution achieves greater safety, energy saving, and efficiency.
Elevator Operation Procedure
The entire system operates by sending commands to the PLC via the control handle. The PLC then executes the corresponding actions based on the commands, controlling a single feedback rectifier frequency converter to drive two 13KW motors. After passing through a worm gear reducer, the motors move up, down, decelerate, and stop on the rack and pinion of a standard section.
INVT Energy Feedback Integrated Solution
HMI: Provides an interface display for on-site limit switch status, frequency converter status, and construction ladder operating status.
PLC: Provides construction elevator status information to HMI, voice broadcast system, and limit switches, etc.
Voice broadcast: Provides voice information on the elevator status and fault information.
Motor: Stops and runs via a worm gear on a standard rack and pinion, and includes a brake coil.
GD300-29 series frequency converter: provides drive for the elevator to move up and down, feeds back the electrical energy generated by the motor during descent to the power grid, and controls the brake to start and stop the car cage.
Using the INVT GD300-29 series energy feedback inverter offers simple control, high power density, and a small footprint. Furthermore, the INVT GD300-29 integrates feedback rectification and inversion, feeding the discharged energy back to the grid, eliminating the need for a braking resistor. This results in low heat generation and low power consumption, achieving energy efficiency and high performance.
When a construction hoist descends, the sudden change in torque upon releasing the brake, combined with the influence of gravity on the cage, can cause slight swaying during startup. INVT addresses this swaying issue with positive torque, achieving a balance between safety and comfort during ascent, descent, and shutdown. This precise control of the construction hoist's ascent and descent ensures greater safety, comfort, and stability.
Scheme Features
l Integrated dedicated filtering function, less interference
It can convert kinetic energy into electrical energy, reducing energy consumption and saving on resistor costs.
Standard input reactor, high power factor
Voice broadcasting and maintenance are relatively simple.
l Stepless speed regulation with low mechanical loss, no contactor required
Small impact on power grid
The dedicated brake logic, controlled by a frequency converter, offers a high safety factor.
The dedicated IF function ensures smooth start-stop operation and high comfort.
The INVT GD300-29 energy feedback integrated machine solution has the advantages of energy saving, high efficiency, simple control, and high reliability.
Since its official mass application in 2017, after more than four years of market validation, the overall energy-saving effect is significant, the failure rate is low, and maintenance is convenient. Taking the actual test data of a certain elevator application site as an example, after adopting INVT's energy feedback integrated machine solution, the overall energy saving rate is over 50%.
Innovation in energy-saving technology is an eternal theme in the construction machinery industry. Energy conservation and emission reduction must rely on the advancement of energy-saving technology. Only by fully understanding the actual production situation of the industry and the technical needs of the construction machinery industry can we better serve the continuous upgrading of construction machinery products.
INVT has over ten years of R&D and application experience in the construction machinery industry, and will continue to provide customers with high-quality products and services through continuous innovation in the future.
