Run-up time
The run-up time is the period of time during which the drive (see Drive) is started and accelerated up to the operating point of the centrifugal pump. It is calculated from the acceleration torque (Taccl.avgd) averaged over the rotational speed (n):
The calculation made with this formula will only produce useful values, however, if the acceleration torque is approximately constant across the entire speed range. Should the TM and TP curves approach each other considerably at certain points, the run-up time must be calculated in sequence using a computational or graphical method. To this end, the speed range is split into sections (Δni) in which constant acceleration torque values (Tbi) are used for calculation. See Fig. 1 Run-up time
The run-up time (ta) is the product of the sum of the individual steps: See Fig. 1 Run-up time
The run-down time (tdown) is calculated in the same way as the run-up time. The only difference is that the acceleration torque (Tbi) is replaced with the starting torque TPi = f(n), which produces a load, or deceleration, torque in this scenario:
