Electrical issues

[Mich48041]

There is an unprotected yellow wire running between the control board and the voltage regulator. If this wire shorts out to ground, it will get extremely hot. This wire should be protected by a fuse. The only way to shut off the current is to shut off the master switch.

The "MAIN BUS" fuse is not really a main fuse. Pulling it will not kill power to any of the other fuses. The MAIN BUS fuse is actually an alternator fuse and should be relabeled "ALTERNATOR".

The 22,000?f capacitor on the control board is not protected from alternator current by a fuse. If this capacitor shorts out and makes smoke in the cockpit, the only way to shut it off is with the master switch.

The stall warning circuit has its own fuse. But the stall warning audio tone is sent to the audio amplifier which is powered by the com stack fuse. If the com stack fuse blows for whatever reason, the stall warning will not be heard.

The rubber grommet through the firewall is a fire hazard. Some type of metal bushing would be better, if available.

The Amp Meter shown on Van's schematic is actually a shunt for the Dynon ammeter. This shunt (on the control board) is part of the circuit from the battery to the main bus. This is not an issue or problem, but could be helpful information.

Joe

 

[rvbuilder2002]

There is an unprotected yellow wire running between the control board and the voltage regulator. If this wire shorts out to ground, it will get extremely hot. This wire should be protected by a fuse. The only way to shut off the current is to shut off the master switch.

Standard aircraft practice. There are 10's of thousands of aircraft flying (RV's included) that rely on the pilots use of the master switch to isolate the battery or alternator feed if it should be required.

The "MAIN BUS" fuse is not really a main fuse. Pulling it will not kill power to any of the other fuses. The MAIN BUS fuse is actually an alternator fuse and should be relabeled "ALTERNATOR".

More standard practice - protecting the alt input, not the battery feed.
Maybe it could be labeled better but I believe the POH covers what its function is.

The 22,000?f capacitor on the control board is not protected from alternator current by a fuse. If this capacitor shorts out and makes smoke in the cockpit, the only way to shut it off is with the master switch.

Yep...more standard and done in compliance with Rotax's recommendation for teh engine part of the electrical system.

 

[Mich48041]

Standard practice is to protect wires

Standard aircraft practice. There are 10's of thousands of aircraft flying (RV's included) that rely on the pilots use of the master switch to isolate the battery or alternator feed if it should be required.

I agree with that. But I am talking about a different wire, the small gauge yellow wire that connects to the "C" terminal of the voltage regulator. Other RVs do not have this wire. It is a hot wire that passes through the firewall and needs to be protected by a fuse so that it does not melt in case of a ground fault . Most hot wires on an aircraft need to be protected by a fuse or circuit breaker. An exception is the large gauge wire from the master contactor to the panel. Standard practice is to protect wires with circuit breakers or fuses, not by shutting off the master switch after a wire smokes.

More standard practice - protecting the alt input, not the battery feed.
Maybe it could be labeled better but I believe the POH covers what its function is.

I agree that it is standard wiring practice. The 30amp fuse protects the alternator output wire from excessive battery current in case the alternator shorts out. (The Rotax alternator does not have an input.) My point is that it is labeled wrong, not wired wrong. Most aircraft have a circuit breaker or fuse labeled "Alternator", not "Main Bus".

Yep...more standard and done in compliance with Rotax's recommendation for the engine part of the electrical system.

OK, I concede this point. The capacitor is unlikely to fail.

In my original posting, I was not complaining or saying that the electrical system is a poor design, except for the unprotected yellow wire and the mislabeled 30amp fuse. As for the other issues, my intent was to point out characteristics of the electrical system that others might not be aware of, not there is necessarily a problem. So do not be too hard on me, Scott.
Joe