Section 7 – Airframe and Systems description
ELECTRICAL SYSTEM
18. ELECTRICAL SYSTEM
Primary DC power is provided by two engine-driven generators which, during
normal operations, operate in parallel.
Each generator is rated at 14,2-14,8 Vdc, 40 Amp, and it is fitted with an integrat-
ed regulator, which acts to maintain a constant output voltage, and with an auto-
matic overvoltage device protecting the circuits and the electric components from
an excessive voltage caused by generator failures.
The power rating of the each generator is such that if one generator fails the other
one can still supply the airplane equipment to maintain flight safety.
Secondary DC power is provided by a battery (lead type - Gill Teledyne G35, 12
V, 38-Ah in 20h run time) and an external DC power source can be connected to
the aircraft DC distribution system.
On the instruments panel, right side, it is installed a voltmeter/ammeter. The am-
meter section can indicate the current supplied by either left or right generator
switching a dedicated selector.
There are five different busses (make reference to Figure 11):
• Battery bus
• LH Generator bus
• RH Generator bus
• LH Avionic bus
• RH Avionic bus
The distribution system operates as a single bus with power being supplied by the
battery and both generators but it is possible to separate the left busses from the
right busses when required by means of the Cross Bus switches.
All electrical loads are divided among the five busses on the basis of their im-
portance and required power: equipment with duplicate functions are connected to
separate busses.
The Battery bus, which supplies the most important loads, is energized from three
sources: the battery and both generators. This allows the bus for remaining active
also in case of two independent faults in the supply paths.
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