Rockwell Automation 150 MNL/SMC DIALOG+/APP-PROD GUIDE - Manual (Page 158)

Reduced Voltage Starting 8-5
The motor speed can determine the amount of current surge that
occurs at transition. Transfer from reduced voltage to full voltage
should occur at as close to full speed as possible. This also minimizes
the amount of surge on the line.
The following figures illustrate transition at low motor speed and near
full speed. The transition at low speed shows the current surge as
transition occurs at 550%, which is greater than the starting current o
400%. The transition near full speed shows that the current surge is
300%, which is below the starting current.
Figure 8.5 Transition at Low Speed
Figure 8.6 Transition near Full Speed
600
500
400
300
200
100
%
Full
Load
Curren
0 % Speed 100
600
500
400
300
200
100
%
Full
Load
Curren
0 % Speed 100