Westerbeke 20B TWO/30B THREE - ELECTRICAL SYSTEM

ELECTRICAl SYSTEM
Engine 12-Volt DC Control Circuit
The Westerbeke modles 20B TWO and 30B THREE propulsion engines each have a 12-Volt DC elec-
trical control circu~, as shown on the wiring diagrams which follOW. Refer to these diagrams when trou-
bleshooting or servicing electrical components on the engine.
CAUTION
To avoid damage to the battery charging circuit, never shut off the engine battery switch whDe
the engine is running_
However. shut oIfthe engine battery switch to avoid electrical shorts when working on the en-
gine electrical circuit
Battery Specification
The minimum recommended capacity of the battery used in the engine's 12-Volt DC control circuit is 90-
125 AmperHlours (minlmum)_
CAUTION
When quick-charging the battery with an external charger, be sure to disconnect the battery
cables from the battery_ Leaving the charging circuit connected whDe quick-charging wDl
damage the aItemator's diodes.
Alternator
CAUTION
When testing the alternator circuit (charging circuit), do not use a high-voltage tester such as
a megger; damaged diodes could resuil
During
high-speed operation of the engine, do not disconnect the positive terminal of the bat-
tery from the B terminal of the alternator, nor disconnect the negative terminal of the battery
from the ground.
When cleaning the engine with a steam cleaner, be careful to keep steam away from the alter-
nator_
~ WESTERBEKE
Engines & Generators
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