PI Manufacturing AC generators - Manual (Page 13)

4.4.4.4 TYPE MX341 AVR
The following 'jumper' connections on the AVR should be
checked to ensure they are correctly set for the generating set
application.
Refer to Fig. 4 for location of setting links.
1. Frequency selection terminals
50Hz operation LINK 2-3
60Hz operation LINK 1-3
2. Stability selection terminals
Frame UC22 LINK A-C
Frame UC27 LINK B-C
3. Sensing selection terminals *
LINK 2-3
LINK 4-5
LINK 6-7
4. Excitation Interruption Link
LINK K1-K2
Fig. 4
4.4.4.5 TYPE MX321 AVR
The following 'jumper' connections on the AVR should be
checked to ensure they are correctly set for the generating set
application.
Refer to Fig. 5 for location of setting links.
Fig. 5
1. Frequency selection terminals
50Hz operation LINK 2-3
60Hz operation LINK 1-3
2. Stability selection terminals
Frame UC22 LINK A-C
Frame UC27 LINK B-C
3. Terminals K1 - K2
Excitation circuit breaker closed.
If this option not fitted, K1 - K2 linked at auxiliary terminal
block.