i plan to put AC drive in crane motors that are currently slip ring motors, since ac drives are made for squirral cage induction motors we can short the rotor terminals and put them? Is there any category of special carne duty ac drives ?
Variable frequency drives VFDs) can be connected to slip ring induction motors with shorted rotor terminals. Because of ringing voltage transients that occur at the waveform switching transition points, VFDs cause voltage stresses on the motor insulation. Motors rated for VFD use are recommended, but older motors can be used. Output reactors or dv/dt filters are recommended for use with older motors. Most VFD suppliers can provide detailed recommendations. Many suppliers have experience with crane retrofits and can provide information and VFD features for coordinating the VFD operation with friction brake controls etc.
