static calculation takeup tension vs actual dynamic value

Dear experts:

As we all know that we set the takeup tension according to static calculation such as starting, running, stoping and braking. but all these tension values are based on rated load such as 4000 t/h (or 5000, 6000), but when the load changed to 20% or some like that of rated load, the tension will adjust automatic to keep running value of rated load, could anyone can give some coments:

1. can we adjust the tension dynamiclly with the load vary?

2. if we don't adjust and keep the takeup tension as static cal ones, what will be happen? does the belt sag will be less 1%? what will be happen with less sag?

3. are there any other disadvantages of the system when it is running with less load but high takeup tension?

4. is there an experinced format between takeup tension and actual load(not static cal)?

look forward to your reply!

thanks in advance! ■