Asynchronous motors in control mode VFCPLUS

The VFCPLUS control mode allows dynamic use of the entire speed range of the drive. Reversing and moving through the speed 0 are also possible.

However, continuous operation of asynchronous motors at low speeds is not possible. The minimum speeds that must not be permanently undercut during operation without encoder are:

  • Motoring operation: 1% of the asynchronous motor nominal speed
  • Regenerative operation: 10% of the asynchronous motor nominal speed

INFORMATION

Lifting application without encoder
The control must be designed in such a way that the direction of rotation can only be changed from an idle state (with the brake applied).

When determining the maximum speed, observe that the breakdown torque MK is reduced in a quadratic relationship in the field weakening range.