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grdev
02-23-2016, 09:53 AM
I have a Model 3 wiring diagram. On the print the triangle with the letter P inside, is that the same as ground? is there actually a grounding bar that is used? On the starter it shows a grounding symbol, so I wondered what the difference was.
It shows something that looks like a rheostat labeled lighting coil that goes in to the voltage regulator. Is that the winding from the engine? Also why would you have an inline fuse off the regulator instead of putting the fuse holder in the panel, any reason? Also not quite sure about the relays. I would assume R3 is for the starter but not quite sure about R1 & R2. Are these special relays?

Thanks for any info:confused:

Av8r_Sed
02-23-2016, 04:53 PM
Can you post the diagram you're working from??

grdev
02-23-2016, 05:36 PM
actually I believe it is the one you have for the KITFOX 111 Message 3 WIRING SCHEMATICS it is page one of 4. I would like to see all four pages if possible.

I'm used to reading ladder schematics, and it is a bit hard for me to follow some of these drawings, but I think I have it figured out now. In my world you would never switch the neutral wire, or in this case the negative wire. It also looks like they use a white wire for positive. Is there a key to the wiring symbols used in this drawing?

Av8r_Sed
02-23-2016, 07:30 PM
Pages 2 through 4 never were completed. They were going to show the connections to the original Westach quad gauge (now an MGL E-1), TinyTach, antennas and such. The manufacturer's wiring diagrams for these were sufficient and are included in my maintenance manual.

The P's on the diagram is a local panel ground block http://www.bandc.aero/grounding-supplies-battery-cables.aspx with multiple blade style push on terminals. I used the bottom most engine mount bolt as the main ground for the airframe. It connects an engine bonding braided wire, Starter ground lead and connection to the P panel ground block.

That's not a rheostat, but the stator lighting coil in the engine. Switch 1 controls master relay R1 as well as switching the charging circuit via relay R2. I did it that way so I could run off just the battery. I didn't want a blown regulator or shorted lighting coil take down the electrical system. R3 is the starting contactor. R1 & R2 are normal plastic enclosed relays with push on blade terminals. I chose the in-line fuse to keep that high current wire short. If it blows I still have battery power and my MGL E-1 low voltage alarm notifies me I have an issue.

Switches S1 & S6 are special with internal connections from B&C Specialty: http://www.bandc.aero/toggleswitch-doublepole.aspx
Note the part number 700-2-10 on the drawing.

All wires have heat shrink markers on both ends, hence the somewhat randomly assigned numbers in the green bubbles.

It's not terribly unusual to switch return leads on 12VDC systems since there is little shock hazard.

Most people will tell you to install individual toggle switches for the ignition modules instead of the R-L-Both ACS keyswitch I've got.

I replaced the Rotax regulator/rectifier with a motorcycle style unit. Most people think the KeyWest regulator is pretty bulletproof.

So far I haven't had any electrical issues in the first 200 hours.

Good luck and feel free to bounce any other questions my way.