
Installation Instruction
23.1.07
Panda_12mini_PMS_Digital_s00865_Installation manual.V02 - Chapter D: Installation Instruction Page 81
D.11 Instructions on preventation of galvanic corrosion
Galvanic corrosion
If several machines are connected by a common electrical potential (e.g. mass) and the system is
also still in contact with other metal parts (e.g. the trunk of a neighbour ship), always assume that
the different construction units proceed different electrical voltage, which affect on the entire
system and the construction units. DC voltage causes an electric current, if in the environment of
these parts electrically leading liquids (electrolyte) are available. Also calls "galvanic process".
The electrical charge of the negatively charged ranges (anode) is led to the positively charged
range (cathode). The negatively charged part (anode) "is sacrificed" thereby, i.e. that the electrical
particles at the surface of the material cause decomposition with this chemical process. Since alu-
minum is an electrically negatively charged metal, aluminum will play the role of the anode com-
pared with most remaining metals. This applies in particular opposite copper, brass, and steel,
high-grade steel etc.. These metals are positively charged.
In order to protect the generator housing
against corrosion and against elecroly-
sis, the terminal block with the cooling
water connecting pieces takes the func-
tion of a sacrificial anode.
Fig. D.38: Cooling water connection block
Several measures must be considered when making the installation, so that bimetallic corossion
can be avoided as much as possible:
• Electrical isolation of the water pump. Synthetic washers and synthetic distant plates are atta-
ched beneath the water pump, so that the potential difference between the generator and raw
water is interrupted.
• Separation of the water columns (between raw water and generator) after switching off. This can
either be a stop valve turned by hand. (BEWARE! The valve must be closed after each operati-
on). Or by the installation of an automatic ventilation valve. In this case the valve opens and shuts
automatically.
• Connecting all components (hull outlet, generator, heat exchanger etc.) to a common potential.
For this all elements are connected by means of a cable (earthed).
• Strict separation of the generator from 12V ship mains, that means earth free installation of the
12V system (generator installation and general ship mains).
Please take more details from the information pack "Bimetalic Corrosion (Electrolysis)", which
You can order from ICEMASTER gratis.