The amount of {HEAD ~ current} shunted is determined by the highest voltage level of {TAIL ~ the control buses} 30a a 
The amount of { HEAD ~ current } shunted is determined by the highest voltage level of { TAIL ~ the control buses } 30a a
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH