3412 PEEC And 3412/3500 MUI Engine Overspeed
The magnetic speed pickup (MPU) tells the control board the engine speed. The control board compares engine speed to the overspeed setpoint. The overspeed setpoint is set at either 118% or the overspeed setpoint is set at 125% of rated engine speed. The control board compares engine speed to the overspeed setpoint (either 118% or 125%). When the setpoint is exceeded, the control board causes a shutdown fault. The following events occur during a shutdown fault.
- The engine is shutdown.
- The air shutoff is activated.
- The shunt trip output is activated.
- The overspeed indicator is activated.
- The optional general alarm relay is activated.
The overspeed setpoint may be either 118% or 125% of rated engine speed. The setpoint must also be adjusted for a precise setting. The SW2 switch (4) is used to select the overspeed setpoint. The "OSSET" potentiometer (5) in conjunction with the LOCAL indicator (7) is used to adjust the selected overspeed setpoint. For the overspeed setpoint adjustment procedure, see Testing And Adjusting, "Engine Overspeed - Adjust".