Bently Nevada 3300/20-03-01-01-00-00 Dual Thrust Position Monitor

Since thrust measurements rely on the gap voltage of the input proximity probe, a transducer failure 

(with gap out of range) can be misinterpreted by the monitor as thrust position movement, triggering 

false thrust alarms. For this reason, Bently Nevada LLC does not recommend using a single probe for 

thrust position applications. Instead, such applications should utilize two proximity probes monitoring 

the same collar or shaft, with the monitor configured for AND voting—where both transducers must 

simultaneously reach or exceed their alarm setpoints to actuate the monitor’s alarm relays. This 2-

out-of-2 (AND) voting scheme optimally prevents both false trips and missed trips. While the 3300/20 

monitor can be programmed for either single (OR) or dual (AND) voting, dual voting is strongly 

recommended for all thrust position applications.