T

Taz

Member
OK, I just noticed an issue...I think, any ideas;

I am 90% done with electrical (I thought) and just discovered that my main bus is getting some power all the time (with batt connected but Master Sw off). I happend to bump the flap switch (main bus) and it started clicking as though it was trying to go, but didn't have enough juice. I checked the lights - same thing, they came on real dim. Those are the only two things I have wired up on the main bus so far, but clearly the main bus is getting some level of power from the batt (through the master relay) even with the Master Relay off/open...or at least with the switch in the off position. With the aircraft batt disconnected there's no power to the main bus (I guess that's a no-brainer) and the master switch does make the normal thunk of connecting the master relay and letting full juice to the main bus - full/brighyt lights, flaps move as expected, etc.

I don't get it, I thought the master relay is all or nothing - am I completely messed up here or is this a bad relay...or something else? :confused:

Thanks,
Brian

RV-7, N9823W
Finishing up Electr & Firewall Fwd
 
voltage when master is off

Better see how much voltage first. Then check for poor ground at battery. Then check the polarity of the protection diode on the relay.Could be a combination of all three. Why do you have the battery connected when wiring? Use a good VOM and start at the relay input and check continuity and shorts without the battery hooked up of course

Hope this helps a little
Tyler
 
Thanks for reply

Hmmm...you had the same thing and it worked itself out? I guess that's good news and I'll keep going, but I'm not thrilled with the idea of the main bus being hot (even at a low current/amperage) whenever the batt is connected.

Anyone else notice this anomoly early on - did it also work itself out?

Thanks
 
Taz said:
Hmmm...you had the same thing and it worked itself out? I guess that's good news and I'll keep going, but I'm not thrilled with the idea of the main bus being hot (even at a low current/amperage) whenever the batt is connected.

Anyone else notice this anomoly early on - did it also work itself out?

Thanks
Click to expand...

Keep in mind that in my case the leakage current was very small. Only enough to turn on the ALT warning light which was an LED. Anything bigger would do nothing. Try flipping it on and off real fast a few times. This seemed to stop the leaks on mine originally.

Now my master does not leak anything.

If yours has enough leakage to turn on incandescent lights and flap motors, I would start looking for the issue and maybe change the relay out for a known good one.
 
diode

I would check to make sure diode is installed correctly and even remove it to see if it stops.

Jay
 
Master

Tyler - thanks, the diode polarity is good, I'll check the voltage and grounds though. I don't have the batt connected while wiring, that's prob how I got this far without noticing this issue. I just happend to connect the batt this AM for something else (OK I wanted to play with the EFIS to motivate myself to keep working) and happened to bump the flap sw before I turned any switches on.

I am still curious if many others noticed this leakage?

Thanks,
Brian
 
Master

OK, too many replies to keep up with - thanks! My flaps wouldn't actually do anything, just click a little - and only the tail light (Aero LED) is connected currently and it came on real dim.

Anyway - I'll check everything, measure voltage and (if low) flip switch a few times rapidly. I'll let you all know what I find in a few hours.

Brian
 
My Stupid Mistake is fixed

Ever have one of those mornings when you wonder if you should really be building an airplane in your garage? I just did and it pains me write this...but in case anyone else can benefit...

Long story short - The Diode was installed to the wrong terminals, I had it running from the master sw input (small center term) to the output/starter relay side rather than the battery/input side. Seems like a simple mistake, but that's what scares me - what else might I make a 'simple mistake' on? Anyway, it was an easy fix and things now work as advertised...I'm just glad I decided to waste some time this AM by connecting the battery (to play with the Dynon) and then accidently bumped a switch - maybe someone was looking out for me.

I appreciate all your inputs - Jay, at first I thought it was silly to disconnect the Diode...but I did, and that was the path that made me realize what I had done.

Thanks all.
Brian
 
Glad I was able to help. Still very early in my build so I usually can't help much. Being an avionics tech for a living though I was finally able to help as so many others have helped me. That is what makes this site and rv'ers so great.

Jay
 
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