STEMME S12, Maintenance Manual

Page: 86 / 290

DOCUMENT NUMBER:
L500-912.820 ISSUE JUL 20, 2016
AMENDMENT: 00
DATE: --
CHAPTER- PAGE 3-52
MAINTENANCE MANUAL STEMME S12
3.7.14 ENGINE RPM INDICATING SYSTEM (ATA 77-14-00)
3.7.14.1 DESCRIPTION
The RPM signal is delivered by a pick-up coil at the rotating magnets of the internal generator
to the tachometer input of the Turbocharger Control Unit (TCU). The TCU provides an output to
which the electrical tachometer on the instrument panel is connected. The tachometer is wired
with shielded AWG22 wire.
The RPM signal is secondarily used to trigger a frequency relay which activates the field circuit
for the belt-driven alternator.
The tachometer fuse is located at the instrument panel fuse holder (engine bus).
3.7.14.2 PARTS SPECIFICATION
Pick-up and tachometer are part of the engine, their specifications can be found in the
ROTAX 914 Maintenance Manual.
3.7.14.3 OPERATION
The engine RPM indicating system does not require operation actions by the pilot.
3.7.15 CYLINDER HEAD TEMPERATURE INDICATING SYSTEM (ATA 77-22-00)
3.7.15.1 DESCRIPTION
The CHT indicating system measures the cooling water temperature on two of the four cylinder
heads of the ROTAX 914 engine. The temperature signal is generated by resistive type probes (Pt-100
characteristics) and displayed to the pilot by one pointer-style gauge for each side of the engine.
The indicators share their fuses with the oil temperature resp. pressure indicator. The fuses are
located at the instrument panel fuse holder (engine bus).
3.7.15.2 PARTS SPECIFICATION
Part STEMME p/n Manufacturer p/n
Oil Temperature Indicator 831.241 UMA T12113R150C050 TSO
Temperature probe RTD
(Resistance Temperature Detector RTD)
831.243 UMA 1B4R
3.7.15.3 OPERATION
The CHT Indication system does not require operation actions by the pilot. Scale markings of
operational limits and instructions to the pilot about corrective actions in the case of exceeded
limits are defined in the S12 AFM.