We have 8 nos. of cooling tower fans. During commissioning, we have been facing frequent tripping of the the fans. The gear box is Flender make, blade CoolFlow. The accelorometers are stud mounted on the gearbox. The problem, comes during start up. As soon as the fan starts, it trips and panel shows reading more then trip setting. If we start again, the vibration does not rise to tripping value and fan runs smoothly.Also after 2 to 3 days running, it may trip randomly. We changed the accelorometer adaptors , type of threads , used thread locker to avoid loosening of accelorometer. There is no other source of high vibration nearby. I have taken the spectrum . I will post it later on. The propeller shaft is approx. 4 meters long with pin and bush couplings on both sides.
Anybody faced such problems. Pl. share your experience.
Regards
Irshad

This message has been edited. Last edited by: AKHTAR,

so its only one of your 8 fans that does this? sounds like you got a wire loose or something like that, or maybe the wire is pinched somewhere and a disturbance of some sort is making the wire contact metal or??

Jonesy,
This is not the problem with one fan. Earlier all fans were having either starting tripping or random tripping problem. After doing modifications in adaptor threads, now problem remains in two fans . First start is a failure. Later start is successful.
Regards
Irshad