VFD for stair press fan making high pitched winding noise

[Nathan_F]

Total of 3 stairwells, specifically when the elevators are running the VFDs for the stair press fans makes a high pitched noise for the duration of the elevator moving, it could also be the Current Transformer in the VFD itself, hard to tell. Any clues on how to go about this?

 

[PaulMmn]

Are the elevator shafts open to the stairwells?? Maybe air pushed out of the elevator shaft is pushing back against the SPFans.