Man D 2866 LE 401, Repair Manual

Page: 121 / 138

Transmitters
120
Checking the coolant temperature transmitter by measuring the resistance
0
20
40
60
80
100
120
140
160
180
200
220
240
260
280
300
0 10 20 30 40 50 60 70 80 90 100 110 120
_
C
Ω
1
2
Dip temperature sensor up to the lower edge of the hex section into a mixture of water and 30 % anti–
freeze/anti–corrosion agent. The liquid must be circulated during this measurement. Check the temperature
with a thermometer as the liquid is heated. Measure the resistance and compare it with the calibrated
curves (
_
F = 1.8
_
C + 32).
Curve 1: Temperature transmitter for 1 electrical instrument
Curve 2: Temperature transmitter for 2 electrical instruments
Temperature transmitter for 1 electrical instrument: checking values and tolerance of transmitter resistance
Temperature
_
C 40 60 90 100
Resistance
Ω
296.0 134.0 51.2 38.5
Tolerance –
±
13.5
Ω
=
±
4
_
C
±
4.3
Ω
=
±
3
_
C
±
3.0
Ω
=
±
3
_
C
Temperature transmitter for 2 electrical instruments: checking values and tolerance of transmitter
resistance
Temperature
_
C 60 90 100
Resistance
Ω
67 25.60 19.25
Tolerance
±
6.5
Ω
=
±
4
_
C
±
2.1
Ω
=
±
3
_
C
±
1.5
Ω
=
±
3
_
C