Coresense locked rotor fault with stream compressor with vfd

Hi all,

its has been a while but I've been out of industry.
I just commision a Copeland stream with Coresense motor protection. My preference has alway been Bitzer for recips. But I thought I give the stream a go on as the where priced a little better.

It runs fine Dol start has the usual discus chug from the comp. but when I run the compressor with the VFD that is fitted. It some times trips the coresense protection with locked rotor fault. It doesn't do it all time. I have caught it twice with this fault. What is weird is the compressor gets away normal, no locked rotor but after 5 second cuts out with rotor lock fault.I have set the vfd to start at normal frequency 50 Hz but it still trips periodically.

I have had similar problems with Int 69 modules from Copeland running vfd in the past tripping. Has any one had similar proplems with Emerson coresense. And is so a solution to stop this happening. I will get in contact with Emerson next week but I though I would ask the experts in the industry first!

Cheers