When a VFD displays negative values, it often indicates a reverse rotation direction. Reversing the direction is usually a simple adjustment in the VFD's settings.
Now, let's address the strange old radio-like sounds. These peculiar noises can be attributed to electrical noise interference. When a VFD operates, it generates harmonics and electromagnetic interference, which can manifest as audible sounds resembling static from an old radio. Some VFDs have built-in motor filters that can be enabled to reduce noise. Check if your CHINT VFD has this feature and activate it if available.