6 MJ-5 Control Panel Automatic Mode 
Siemens Industry, Inc.    49 
F LOCK (Forward Locked Mode) 
This mode of operation is intended for use on systems 
where reverse power flow is not anticipated. Tap changes 
are inhibited under reverse power flow conditions. 
 
In this mode, the controller always operates in forward 
mode. The tap changer operates unless reverse current 
magnitude exceeds the I Threshold % set point, at which 
time further tap changes are inhibited. The tap changer 
resumes operation when the reverse current drops below 
the I Threshold % set point. 
 
In this mode, if power flow does reverse, Demand values 
are not computed. 
 
View Pwr Flow: F LOCK on the <CONFIGURE> menu. 
 
 
 
 
Figure 6.2 Forward Locked Mode 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
R LOCK (Reverse Locked Mode) 
This mode of operation is intended for use on systems 
where forward power flow is not anticipated. Tap changes 
are inhibited under forward power flow conditions. 
 
In this mode, the controller always operates in reverse 
mode. The tap changer operates unless forward current 
magnitude exceeds the I Threshold % set point, at which 
time further tap changes are inhibited. The tap changer 
resumes operation when forward current magnitude drops 
below the I Threshold % set point. 
 
In this mode, when power flow is Forward, Demand values 
are not calculated. 
 
View Pwr Flow: R LOCK on the <CONFIGURE> menu. 
 
 
 
 
Figure 6.3 Reverse Locked Mode