Cessna TURBO CENTURION T210M 1978 Pilot Operating Handbook page 47

CESSNA
MODEL T210M
SECTION 3
EMERGENCY PROCEDURES
ELECTRICAL POWER SUPPLY SYSTEM MAL-
FUNCTIONS
Malfunctions in the electrical power supply system can be detected by
periodic monitoring of the ammeter and over-voltage warning light;
however, the cause of these malfunctions is usually difficult to determine.
A broken alternator drive belt or wiring is the most likely cause of
alternator failures, although other factors could cause the problem. A
damaged or improperly adjusted voltage regulator can also cause mal-
functions. Problems of this nature constitute an electrical emergency and
should be dealt with immediately. Electrical power malfunctions usually
fall into two categories: excessive rate of charge and insufficient rate of
charge. The paragraphs below describe the recommended remedy for each
situation.
EXCESSIVE RATE OF CHARGE
After engine starting and heavy electrical usage at low engine speeds
(such as extended taxiing) the battery condition will be low enough to
accept above normal charging during the initial part of a flight. However,
after thirty minutes of cruising flight, the ammeter should be indicating
less than two needle widths of charging current.
If
the charging rate were
to remain above this value on a long flight, the battery would overheat and
eva porate the electrolyte at an excessive rate. Electronic components in
the electrical system could be adversely affected by higher than normal
voltage if a faulty voltage regulator is causing the overcharging. To
preclude these possibilities, an over-voltage sensor will automatically
shut down the alternator and the over-voltage warning light will illumi-
nate if the charge voltage reaches approximately 30 to 31 volts. Assuming
that the malfunction was only momentary, an attempt should be made to
reactivate the alternator system. To do this, turn the avionics power switch
off, then turn both sides of the master switch off and then on again.
If
the
problem no longer exists, normal alternator charging will resume and the
warning light will go off. The avionics power switch should then be turned
on.
If
the light comes on again, a malfunction is confirmed. In this event,
the flight should be terminated and/or the current drain on the battery
minimized because the battery can supply the electrical system for only a
limited period of time. If the emergency occurs at night, power must be
conserved for later operation of the landing gear and wing flaps and
possible use of the landing lights during landing.
INSUFFICIENT RATE OF CHARGE
If
the ammeter indicates a continuous discharge rate in flight, the
alternator is not supplying power to the system and should be shut down
since the alternator field circuit may be placing an unnecessary load on the
system. All nonessential equipment should be turned off and the flight
terminated as soon as practical.
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