Induction motor 'droop control' on multi-motor coupled loads
simulate this circuit &ndash; Schematic created using CircuitLab
Basically it reduces the speed with regard to the torque. All drives have the same speed setpoint value and they reduce speed equaly if they are all loaded the same. When one of the drive is more loaded, it reduces the speed further and lets the other to accept the extra load. Kind of simple equalization, without cross feedback.
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This is Siemens VFD Droop. Precontrol means an additional torque due to mass of inertia. Ideally would be using selector at position 2 (load torque only) and appropiate Droop factor.