I am a phd student and I got 30% tax ruling for 3 years. For my last year, I change to another university, still as a phd student. I understand that I have to re-apply for 30% tax ruling. However, as I am now more than 30 years old phd student, would you please tell me whether I need to meet the minimum salary requirement (50k) which is not possible for a phd student. Or there will be no problem when i re-apply for the 30% tax ruling?
You mention that you got the ruling for 3 years now, which indicates that it was granted to you before 1 January 2012. This means that for the first 5 years of the ruling you still fall under the old rules, which were applicable before 1 January 2012. The salary requirement is therefore not applicable (yet) in your situation. You will not have to earn a salary of 50k when you change jobs.
From the moment you have been working in the Netherlands for 5 years the new rules become applicable. Then you will have to earn the higher salary.