Autopilot power wiring to servos

[jimsyg]

I have my autopilot power wired from the Avionics buss to a toggle switch on the panel.  I have a disconnect on the stick grip.  The wiring schematic shows that both servo red wires are connected together to the power source and, of course, both yellow wires are connected also.  I have the SV32 servos in an RV9-A with Skyview.

My question is:  The servos call for a 3 amp protection.  Can I run power to both servos through just one 3 amp connection, then up to the toggle switch?  Or do I need two toggle switches, two 3 amp circuits? 

 

[Dynon]

The main purpose of fuses/breakers is to protect WIRING, not the devices. In short, you size your wire to be able to carry the load specified, and then use a breaker/fuse that can accommodate the maximum load, plus some extra, but not more than the wire can handle before burning up. Chapter 11 of this FAA advisory circular is instructive.

Using our stock setup, you want each servo's wiring on its own 3 amp circuit protector in this case. You could switch them together though. In general, we don't recommend actively switching the AP servos separately from the rest of the system. If you choose to, leave it on all the time, unless something is wrong. The disconnect switch is the normal way that you should be disengaging the servos routinely. When the AP isn't engaged, the servos draw negligible current.

 

[jimsyg]

Thanks for the reply. I have been so involved building I forgot to check back for your help on this. I do have them switched together on the panel and the disconnect on the grip. I will fuse both servos separately.

 

[maus92]

Should the A/P servo power be connected to the avionics bus, or the main bus?

 

[Dynon]

We recommend they come on with SkyView. Whether that's with master or your avionics bus doesn't really mater. As for an avionics bus, SkyView itself doesn't require a separate avionics bus one and is designed to be on when the engine cranks so that it can show you oil pressure, Your mileage may vary if other equipment you may also have in the airplane can't take the voltage transients.

 

[maus92]

We recommend they come on with SkyView. Whether that's with master or your avionics bus doesn't really mater. As for an avionics bus, SkyView itself doesn't require a separate avionics bus one and is designed to be on when the engine cranks so that it can show you oil pressure, Your mileage may vary if other equipment you may also have in the airplane can't take the voltage transients.

Thx for the answer - here's a follow up: does the Skyview system resistance to transients apply to all Skyview system components, like the transponder, comm radio, ads-b, intercom, gps?