pots Posted March 16, 2021 Report Share Posted March 16, 2021 Due to version 1.6.2 release I started to reading again Saab 340A Systems Operation Manual. According to electrical system description on page 55 and schematics on page 65 there seems to be hidden emergency battery located somewhere. So it has no switch (always ON), no voltage display and it status is shown only by "EMER PWR" warning light? Quote Link to comment Share on other sites More sharing options...
JGregory Posted March 16, 2021 Report Share Posted March 16, 2021 The Emergency Bus is powered by the normal system or the Emergency Battery when a battery relay is closed (via battery switch). The annunciator "lights up" when there is no power to the bus or, if being powered by the Emergency Battery, if the voltage is low. There is not status indicator in the cockpit. Quote Link to comment Share on other sites More sharing options...
pots Posted March 17, 2021 Author Report Share Posted March 17, 2021 Thanks for reply! Saab 340A AOM seems to be very rare but somehow I found Saab 340B AOM. According to it emergency power supply unit contains a 24 V 5 A·H lead-acid battery and battery heater (to warm the battery for best efficiency). Just curious - is similar solution in 340A? Quote Link to comment Share on other sites More sharing options...
JGregory Posted March 17, 2021 Report Share Posted March 17, 2021 5 hours ago, pots said: Thanks for reply! Saab 340A AOM seems to be very rare but somehow I found Saab 340B AOM. According to it emergency power supply unit contains a 24 V 5 A·H lead-acid battery and battery heater (to warm the battery for best efficiency). Just curious - is similar solution in 340A? Yes. Quote Link to comment Share on other sites More sharing options...
N1K Posted March 18, 2021 Report Share Posted March 18, 2021 (edited) 340A ch.5.1 p.4 Quote 2.7 Emergency power supply Emergency power is supplied by the emergency power supply unit which contains the emergency battery and a battery heater. The battery is a 24 V/5 ampere−hours lead−acid battery. The battery heater will be activated automatically in cold temperatures. The heater warms up the battery for best battery efficiency. When the L BAT BUS is powered from generator or external power, the emergency battery is charged from this bus. The emergency battery begins to supply power to the EMERGENCY BUS when the L BAT BUS voltage goes below 24 V. If the emergency battery voltage drops below 24 V, the EMER PWR light on the overhead panel comes on. This light also comes on if the EMERGENCY BUS is not powered, provide the warning electronic unit (WEU) is powered. Pretty sure its a copy paste system into the B's. That battery is the cockpit supply and is in the avionics rack. There is another, although technically separate, set of battery's for emergency cabin lighting under the cabin flooring. Similar logic, loss of main bus power means I should turn on. Edited March 18, 2021 by N1K Quote Link to comment Share on other sites More sharing options...
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