ST500 | Change start and stop ramp

The start and stop ramps can be set separately on an ST500. A higher starting time reduces the inrush current and can protect the frequency inverter against unintentional switch-off. A higher stop ramp gives the inverter more time to brake the load and can thus protect against overvoltages in the DC bus. For small and light loads, on the other hand, the ramp can be reduced to allow fast acceleration and braking.

F0.13 = 20s (Start ramp from 0 to F0.19 in 20s)
F0.14 = 20s (stop ramp from F0.19 to 0 in 20s)

The start and stop ramps are normally selected in relation to the maximum frequency. This then results in a fixed speed in which the frequency changes (Hz/s), which is then used for each braking or acceleration process. Therefore, if the frequency is lower than the maximum frequency, the acceleration/deceleration process is shortened by the ratio of the actual and maximum frequency.

If this is not desired, the inverter can also be parameterized in such a way that the acceleration and deceleration ramp times always refer to the set frequency and therefore not the frequency change speed but the time required is constant, no matter how small or large the frequency jump is:

F0.16 = 1 Ramp times refer to the target frequency