DETROIT DIESEL 53
Battery-Charging Generator 7.1
Fig. 4. 20 DN Type 250 A.C. Self-Rectifying Generator (Alternator)
Accidentally reversing the battery connections must be avoided.
Never disconnect the battery while an alternator is in operation. Disconnecting the battery may result in damage to the
generator diodes due to the momentary high voltage and current generated by the rapid collapse of the magnetic field
surrounding the field windings.
If a booster battery is to be used, the batteries must be connected correctly (negative to negative and positive to
positive).
Never use a fast charger with the battery connected or as a booster for battery output.
Never attempt to polarize the alternator.
The alternator diodes are also sensitive to heat and care must be exercised to prevent damage to them from soldering
irons, etc.
If faulty operation of an alternator occurs on an engine equipped with an insulated starting motor, check to be sure that a
ground strap is present and is correctly installed.
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