Electrical System - Westerbeke 12B TWO Operator's Manual

ELECTRICAL SYSTEM
Engine 12-Volt DC Control Circuit
The Westerbeke W 128 TWO propulsion engine has a 12-Volt DC electrical control circuit, as shown on the
wiring diagrams which follow on pages 34 to 37. Refer to these diagrams when troubleshooting or servic-
ing electrical components on the engine.
CAUTION
To avoid damage to the battery charging circuit, never shut off the engine battery switch while
the engine is running.
Shut off the engine battery switch, however, to avoid electrical shorts when working on the en-
gine electrical circutt.
Battery Specification
The minimum recommended capacity of the battery used in the engine's 12-Volt DC control circuit is 90 -
125 Ampere-hours (minimum).
CAUTION
When quick-charging the battery with an external charger, be sure to disconnect the battery
cables from the battery. Leaving the charging circutt connected while quick-charging will
damage the alternator's diodes.
Alternator
CAUTION
When testing the alternator circuit (charging cirCUIT), do not use a high-voltage tester such as
a rnegger; damaged diodes could result.
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 wtth a steam cleaner, be careful to keep steam away from the aller-
nator.
Refer to pages 34 to 37 for the two electrical system wiring schematics (one is used for the Captains panel
and the other for the Admirals Panel).
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Westerbeke Diesel Engines