Printable View
I received my shunt and capacitor today and noticed the terminals on the shunt are marked 30A and 50MV there are not any instructions included I think the wires from my rectifier would go to the 50 MV terminal and the 30 A terminal to a fuse then to bus bar is this correct and does it make a difference? Thanks
Hi Greg,
The shunt is not polarity sensitive. The 50MV & 30A markings are just referring to the electrical characteristics of the shunt - they are not identifying the specific terminals that they are near to. I hope that is clear, and helps. It doesn't matter what direction the shunt is installed.
LOL! Do you know how scary this all sounds? I hate electricity. I hope to Heck this Sport Air workshop in October makes this stuff make sense. :(
The shunt is a low resistance path that allows your ammeter to measure a voltage drop. Shunts are wired in series with the circuit you are wanting to measure.
30A is the max current rating of your shunt and 50mV is the voltage drop across the shunt. Using ohms law you can figure the resistance of the shunt by R=E/I or R=.050/30 or around .002 ohms.
Your ammeter will be wired across the shunt terminals. There should be 2 large fasteners (screws) for the aircraft load wires and 2 smaller terminals (screws) for the meter wiring. It is advisable to add a 1A fast blow fuse on each wire going to the meter, just in case...
There are 3 ways to wire a shunt.
1. output of the alternator (measures current from the alternator to aircraft and battery)
2. output of battery (past the master switch) (measures current in and out of battery)
3. before the aircraft load (measures current load of aircraft)
1 and 3 will always be positive current. 2 will show positive and negative current.
Make sure you have a way to protect the terminals of your shunt as they will have full battery current on them when the master is on. Don't ask how I know...
Thanks Jeff. I look at panels every chance I get in an attempt to figure out what kind of stuff I will be wiring into my system. This thing is new to me. Im wondering where I would have learned of this stuff if you hadn't explained it? The Manual doesn't mention this thing to my recolection. Obviously Kitfox can't educate us on everything as they have no idea what we are putting into our aircraft.
Eddie
Maybe I am a bit of an outlier when it comes to tradition; but, I avoided the whole shunt thing by not using an ammeter. An ammeter, in my opinion, tells a person something (which way the current is flowing and how much) but it does not provide certain useful information like a voltmeter (overvoltage/undervoltage). One of the destructive failure modes, to other equipment, of a regulator is not controlling overvoltage.....a 12 volt system running at 16 V rather than 14 like it should will show a charge on an ammeter like everything is hunky-dory, but it will fry a battery. A voltmeter is a simple hot wire to the charging system and a ground. I think both gauges provide information, just that the voltmeter will be instant and maybe provide a little more direct information. But that's just me:o
I agree! Not worth the panel space (if using conventional instruments), and relatively useless information. With a glass panel however, a relatively easy addition to information overload. ;) Just kidding a little - it can be useful under certain circumstances.Quote:
Originally Posted by Dave S
You Kit FOXERS are better than instructions thanks for all the good infro!;)
Agree that an ammeter can provide little info. The most common use is to monitor the alternator output. When your alt starts acting up the meter can be useful. Other than that, who cares what the load is on your system. If its too high you will be melting wires and or popping breakers!
efwd
My album has pics of my panel. Look for jmodguy in the Series 5 group.
I have wired mine mode 1 to tell if the ammeter is putting out. I also have battery voltage. When the battery voltage starts dropping, you can glance at the amps to see if the alternator is putting out a charge.
I'm an electrician and wiring is my favorite part of the build.:D I take the little instruction booklets from each device, scratch out a schematic, wire it up, and draw it in CAD.
covering is not my forte - to each his own