8251-544 WOODWARD

Droop Contact (Isoch-Droop) and Load Sharing Lines

Because the load-sharing-line relay is contained in the control, no relay is 

required between the control and the load-sharing-line bus. Use shielded cable 

and connect the load-sharing lines directly to terminals 10 (+) and 11 (–). 

Connect the shield to terminal 12. When all controls in the system are of the 

2301A type, the shields may be connected continuously between controls. When 

load sharing with different controls, do not connect the shields at the point where 

connections are made to the load-sharing-line bus.

The droop contact for selecting droop or isochronous operation is wired in series 

with the circuit-breaker auxiliary contact between terminal 14 and terminal 16 

(terminal 0 on high-voltage controls). When both the droop contact and circuitbreaker auxiliary contact are closed, the control is in the isochronous loadsharing mode (Figure 2-3, A). In this mode, the internal load-sharing-line relay is 

energized, the droop signal is disabled (permitting isochronous load sharing), 

and the load-matching circuit is connected to the load-sharing lines.

The control is in the droop mode when EITHER the droop contact or the circuitbreaker auxiliary contact is open (Figure 2-3, B). If the droop contact is open, the 

control remains in the droop mode even when the circuit-breaker auxiliary 

contact is closed.

Figure 2-3. Droop Contact and Circuit Breaker Auxiliary Contact

The control is in the droop mode whenever the circuit-breaker 

auxiliary contact is open. If a single prime mover is required to run 

isochronously with an isolated load, turn the DROOP potentiometer 

fully counterclockwise (be careful not to overtorque the pot).