7.3 The isolation transformer A better solution to stop galvanic corrosion is the use of an isolation transformer. In an isolation transformer the incoming electricity is changed into electromagnetism and then changed back into electricity. The input and output are completely isolated and will break the electric circuit between star point – earth conductor – hull – water – star point, thus effectively blocking a galvanic current. Another feature of the isolation transformer is that electrically speaking it is an electricity source, fed by another electricity source. On the output side of the transformer one of the outgoing phases is connected to the hull, whereby creating a phase, neutral and earth, thus guaranteeing a correct functioning of a RCD. An isolation transformer will give the same safety as in a house installation and more. The installation is also completely isolated of electrical problems of surrounding boats. An added benefit is that an isolation transformer is quite often able to raise or lower the incoming shore voltage. This can be useful when 230Vac boat has to connect to a 120VAC supply, or vice versa.
Powered by FlippingBook