Function Diagrams For Speed Synchronization; Syncstart; Up/Down Factor; Figure 10: Syncstart With Speed Synchronization - Danfoss VLT 5000 Operating Instructions Manual

Function diagrams for speed synchronization

SyncStart

When closing the SyncStart contact (Terminal I1), the slave drive accelerates with minimum ramp time
to the speed of the master drive, taking the gear ratio into account. When I1 is opened, the slave drive
ramp or coast to stop. Stop behaviour is selected in parameter 725.

Up/down factor

After the slave has been synchronized to the speed of the master by means of SyncStart (Terminal I1),
the gear ratio can be changed during operation. By means of Inputs 33 Speed+ / Up-factor, or
32 Speed- / Down-factor, the gear ratio can be changed by the value set in Parameter 744 (step width).
This change affects only the slave factor. For more sensitive adjustment of the gear ratio, the gear ratio
digits should be extended and a small step width should be selected.
If one of the two inputs is on longer than the time defined in Parameter 743 (step time), a further step
will be executed.
Example:
Gear ratio i = 22:43
If the step width is equal to 1, the first upward step will result in i = 22:44, which represents almost 3 %.
It would be better to set the ratio as i = 2200:4300. Then the upward step will result in i = 2200:4301,
which represents a change of approx. 0.03 %.
38
Synchronizing controller

Figure 10: SyncStart with speed synchronization

MG.10.N4.02 - VLT is a registered Danfoss trademark