The switch is split to separate the two systems. This causes a large voltage spike backwards across the solenoid.
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Cessna split master switch wiring diagram. It is a dual switch used to turn on the main alternator and main battery. Or these terminals can be ignored for non backlit switch banks. When wiring this switch you can choose if youd like to illuminate it because of the independent lamp attached to terminals 8 and 7. Im looking at the undocumented installation of an avionics master switch. In the process of checking the work that had been done to correct this problem we discovered that whilst running the engine at a high rpm and then turning the master switch off to isolate the electrics the radio and cockpit intercom systems remained live and. This switch is commonly seen in cessna aircraft.
The drawing below is a generic reference drawing. Its a simple 35a current protected spst switch in series with smaller breakers that power to all the com nav gps and xpdr gear on the airplane. The cessna maintenance manual supplies all information needed for this installation. The wiring diagram to the right will show how to wire and power this 12v 20amp on off on 3 way carling contura rocker switch. Wire gauges may vary depending on your electrical loads. The coil in the solenoid is a large inductor.
The switch is designed in a way that the battery must be turned on first before the alternator can be engaged. Aircraft wiring usually consists of tin coated copper stranded wire covered by insulation. Dgr6 1 is the pma replacement for dgr6 c611001 0101 c611001 0102 c611001 0201 and vr600. This completes the circuit to the buss named after the founder of buss fuses years ago and the airplane is powered up. When the master switch is turned off the current through the inductor solenoid quickly disappears. The cessna split master part number 11 15900 does not include any specific wiring instructions.
The positive and negative terminals on the switch are reversible you may wire them in either direction. We have a cessna 150 and have been experiencing problems with a low voltage light coming on during flight which we have now rectified. It does happen to be a 35a switchbreaker installed at the load end of a 12 awg wire from the power bus. The left side of the master switch provides 5 amp power to energize the alternator. Manufactured in the usa. Lamar voltage regulator dgr6 1 fits cessna 150 thru cessna 210 series aircraft.
The diode shunts limits this voltage so it does not get to your avionics and also lengthens the lifetime of the master switch contacts.
Gallery of Cessna Split Master Switch Wiring Diagram
