Merits of inverter drives
Overhead travelling cranes with inverters have the following merits:
- Inverters can keep the load from swinging by smoothing acceleration/deceleration.
Using S-pattern acceleration/deceleration, inverters start and stop cranes more smoothly.
In addition, the vector control without sensors can support stable speed.
- Inverters can control descendent speed.
Usually, hoisting equipment has mechanical brakes to avoid increasing speed in downward operation.
However, inverters use braking resistors for this purpose.
- Inverters can detect overload.
Inverters support the following functions:
Torque limit function
- Inverters can control mechanical brakes with output toruque detection.
VF-S15 and VF-AS1 has special functions for hoist applications.
One of these functions supports mechanical brake control.
- High speed operation at light load
If VF-S15/VF-AS1 detecs a light load, it automatically increases the speed by utilizing tact time reduction.