my fans non stop working

hello guys
my product is 
presicion m5550

I've been using it since 3 weeks. There was no any problem about the fan noise but now it's never stop all the time.
CPU temp is 54°C, and there is no any load of jobs, it almost empty

I just set the quiet mode on dell power manager but noise inreasing when i choose the quiet mode. when i choose balanced mode, noise decreasing but never stop

Any idea about it?

thanks