G900X/G950 Installation and Maintenance Manual – GEA 71
Revision D
190-00719-00
Page 5-16
5.6.2.5
RPM (Revolutions Per Minute) Sensor
Sensor Description:
1A3C-2: Standard mechanical tach drive sender (0-5 volt square wave, 2 pulses per crankshaft rev)
N/T1A9-x-C: Magnetic pickup tach sender (installed on mag bleed port)
General Installation Guidance:
1A3C-2:
1.
Remove the cap from the tachometer drive output (Figure 5-10) from the back of the engine.
2.
Insert adapter tang into slotted keyway in sensor drive port.
3.
Screw tach sensor onto threaded driver port, ensuring that the adapter tang on the sensor aligns
with the slotted keyway in the drive port (Figure 5-11).
4.
Connect the supplied connector to the appropriate inputs on the GEA as referenced in the
G900X/G950 interconnects in Appendix F-J. Secure the connector and wire assembly to an
appropriate location in the engine compartment to provide strain relief.
NOTE
The body of the sensor unit can be offset slightly to eliminate potential interference with
other engine accessories. If the interference cannot be alleviated by offsetting the sensor
directly, the builder may either install a magnetic pickup sensor or use a short tachometer
drive extension cable to remote mount the sending unit to the engine mount (or other
suitable location).
Figure 5-10. Tachometer Drive Output
Figure 5-11. Installed Tachometer Sensor
