"Skyview" Engine Diode, page 45-07 and 42D-25

[Bill_H]

The Skyview update comes with an additional engine diode.
Can anyone tell me why?

The original diode "ES Diode Master" is installed on page 45-07 Revision 4 between the master relay (upper) and the starter relay (lower).

In the Skyview update, page 42D-25, another diode is supplied "ES-00165 Starter Relay Protection Diode." It connects to the starter relay from a new buttsplice in wire WH-K47 (orange).

This is going to be pretty difficult to get to with the engine installed.

What's up with this? A search for "diode" didn't enlighten me. Are newer engine kits being shipped with this extra diode? Is there a later revision than "4" for existing page 45-07 showing this diode to be added?

Bill H.

 

[Mich48041]

Two diodes are also used on the RV-12 that has the Dynon D-180, one across the starter contactor coil and one across the master contactor coil. But the diode across the starter contactor is not obvious because it is located on the control board. Even though the diode is physically located remote from the starter contactor, electrically speaking the diode is connected across the contactor coil. When power is shut off to a coil, the coil generates a high voltage that causes arcing and sparking across the switch. A diode in parallel with the coil shorts out high voltage spikes and thus protects the switch contacts from being burned and pitted.
Evidently the control board that comes with the Skyview avionics package does not include a diode to protect the start-key-switch against high voltage generated by the starter contactor coil. Therefore a diode needs to be added.
Joe Gores