Volvo IPS650, Installation Manual

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Checking electrochemical
corrosion
Tools:
88890074 Multimeter
21504294 Reference electrode
Measuring galvanic current and stray
current in water
Volvo Penta has developed a method for measuring
galvanic current and stray current in water using a ref-
erence electrode.
21504294 Reference electrode (Ag/AgCl)
(1)
is con-
nected to 88890074 Multimeter. The multimeter is
used to measure the difference in potential.
NOTICE! If another multimeter is used, it must have an
accuracy of 1 mV.
Depending on the method used, the results provide an
average voltage for the whole measured object, e.g. a
shaft, or the voltage an individual component produ-
ces.
Examples of such measuring points are rudders and
water inlets etc.
NOTICE! The reference electrode may be used in
water with varying salt levels, or in freshwater.
The process measures the difference in potential
between the measured object and the reference elec-
trode. The reference electrode has a known constant
electrode potential. Thus the measured difference in
potential is always related to a special reference elec-
trode and the same electrolyte, i.e. the same water and
water temperature. Water flow must always be the
same if the results from different measurements are to
be compared.
21504294 Reference electrode
p0005125
88890074 Multimeter
1. Ideally, do not combine the blue 885156 calomel electrode with
the amber 21504294 Ag/AgCl electrode. In such cases the 40 mV
must be added to the measured value from the Ag/AgCl electrode
when comparing with the calomel electrode.
Arrangement and Planning, Electrochemical Corrosion
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