One of the central features of these new inverters is Direct Torque Control (DTC), which makes it possible to directly control the speed and torque without having to track speed and position for travel applications through sensors and encoders.
“As a result, the inverters offer highly dynamic vector control of long-travel, cross-travel and hoist drives, thus reducing the amount of sensitive sensor technology required on the crane itself,” the company said.
The inverters are equipped with Demag CraneControl, a complete application program for crane drives.
“This means that you have ‘on board’ precisely the functions that a crane manufacturer requires,” Terex Material Handling said.
These functions include brake control with brake feedback evaluation, torque memory and a system check. It is also possible to select field weakening operation with partial load and synchronous control for operating several hoist units.
Saved as complete software solutions in the application program of the Dedrive Pro 880 inverters, the company said these functions considerably reduce the costs and work involved in engineering for the crane manufacturer.
“The crane operator can thus make use many practical and innovative control functions,” said the company and added: “The model-based load-sway reduction is a crane-specific function of the Dedrive Pro 880 inverter that is as important as it is innovative. This model-based function without sensors effectively reduces the load sway based on a mathematical model. In practice, this function paves the way for both considerably higher handling rates and even safer crane operation.“
The application program also includes the crane-specific service functions, such as elapsed operating time counter for the crane, load spectrum for the hoist unit and starting frequency for the brake. Remote diagnosis allows users to view the crane control system from anywhere and makes it possible to output fault and error messages.
The new Dedrive Pro 880 frequency inverters are available as a complete series in the Demag drive systems product range for crane drives with 0.55 kW to 560 kW power ratings.
Nine wall-mounted units with varying frame sizes (R1 to R9) and two free-standing models (R10 and R11) complete the range.
