Cirrus SR-20 N699YZ, Руководство пользователя

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supply the essential distribution bus which powers the ESSENTIAL BUSES.
Notice the diode between the two distribution buses. If BAT 2 and ALT 2 fail, BAT
1 and ALT 1 will power their normal buses
​ AND
​
the essential busses. If BAT 1
and ALT1 fail, BAT 2 and ALT 2 will power
​
ONLY
​
their essential buses. The
remaining buses will receive no power.
129. Return to the Electrical System on page 7-53 of the POH. Describe alternator
1: ALT 1 is a gear-driven, internally rectified (converts AC to DC), 100-amp
alternator that’s mounted on the front of the engine. It is regulated to 28.0 volts.
130. Describe alternator 2: ALT 2 is a belt-driven, internally rectified, 28 amp
alternator mounted on the accessory at the rear of the engine. It is regulated to
28.75 volts.
131. Describe both batteries: BAT 1 s a 24-volt, 10-amp-hour battery mounted on
the firewall. BAT 2 is composed of two 12-volt, 7-amp-hour batteries connected
in series to provide 24 volts and located behind the aft cabin bulkhead.
132. Why do you think that ALT 2 is regulated to a higher voltage than ALT 1 (This
is not explained well in the POH)? Voltage is like water pressure. Because ALT 2
has more pressure, it prevents ALT 1 from powering the essential buses during
normal operation of the electrical system. ALT 1 can power the essential buses
only if ALT 2 fails.
133. Why should the batteries and alternators not be turned off in flight? Because
both alternators are self-exciting (not self-starting) and require battery voltage
only for field excitation in order to start operating.
134. What equipment is on the essential buses? Annunciator lights, turn
coordinator, PFD, stall warning, battery 2, alternator 2, autopilot, and COM 1 and
GPS 1 (ADA HRS 1, STBDYATTD)
135. How can you prove what the essential buses power? With the engine running
on the ground , turn off ALT 1 and BAT 1, but leave ALT 2, BAT 2, and the
avionics switch on. Now observe what works and what doesn’t work.
136. How can you check to see if the distribution buses isolation diode has failed?
Turn on only BAT 2 and the avionics switch and COM 2 or NAV 2. If either one
works, the diode has failed.
Cirrus SR-20 POH Summary
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