Rotax 915 i A series Maintenance Manual page 426

The temperature sensors which are mostly used in
the engine are NTC (Negative Temperature Coeffi-
cient) and operate in the opposite manner i.e. the re-
sistance value essentially falls when the temperature
rises. This must be taken into account when measur-
ing at temperatures which differ from the specified
values. The relationship between the resistance and
the temperature can be found in the respective dia-
gram of the relevant sensor.
The resistance value of a temperature sensor can
appear to be in working order at ambient temperature
but defective at other temperatures. If in doubt, re-
place the sensor.
NOTE
It should be remembered that the static meas-
urement is only meaningful for the determined
temperature ranges. Exact information can be
obtained if the sensor has been tested over a
wider temperature range.
Figure 18.24
R Ohmmeter
VOLTAGE MEASUREMENT
General note
76–70–00
Page 18
August 01 2018
BRP-Rotax
MAINTENANCE MANUAL HEAVY
10076
T Temperature sensor
ATTENTION
Voltage supply: The secondary side of the igni-
tion unit is an exception to the following in-
structions! The ignition voltage can be up to 30
000 volts! This high voltage must only be
measured with a special measurement unit or
an oscilloscope with a special test probe.
Voltage can be detected with a simple test lamp or a
voltage tester. However, this only indicates whether
there any voltage is connected at all. To check the
level of the voltage present, a voltmeter (= multi-
meter) must be connected.
Step Procedure
1 The voltmeter must first be adjusted to
the measurement range in which the volt-
age to be measured probably is. Voltages
on the engine are generally no higher
than approx. 28 volts.
2 Connect the cables of the measurement
unit parallel to the consumer.
Voltage
supply
Figure 18.25
Parallel-connected
V
voltmeter
V R
10077
R Consumer
Effectivity: 915 i A Series
Edition 0/Rev. 0