Van's Air Force
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Insulate ammeter shunt
- Thread starter jimgreen
- Start date
hydroguy2
Well Known Member
and here's is another way to skin that cat.
I'm using the shunt as indication of alternator load. Therefore the only time mine is hot is with the master shut. It is also under the cowl.
I thought about using a piece of baffle rubber and making a flap, but in the end, I will do nothing. Only time there is any chance of sparking or arcing is during troubleshooting periods, which hopefully will be very few, far between and brain should be engaged.
YMMV, I chose lighter is better
I'm using the shunt as indication of alternator load. Therefore the only time mine is hot is with the master shut. It is also under the cowl.
I thought about using a piece of baffle rubber and making a flap, but in the end, I will do nothing. Only time there is any chance of sparking or arcing is during troubleshooting periods, which hopefully will be very few, far between and brain should be engaged.
YMMV, I chose lighter is better
Brantel
Well Known Member
Hey Jim,
My shunt was on the engine side of the firewall...The rubber boots on the wires covered the screw part of the connections..I plan on putting some liquid tape on the shunt part and the other areas that are electrified.....have not got around to that yet. Not much that can come into contact with my shunt unless I have other big problems. Since I do not work on the engine most of the time with the master on, there is little risk of dropping a wrench or other tool on there.
How the heck you gonna get to them fuse blocks after that top skin is riveted on?
Also, I recommend fusible links close to the shunt on the wires going from the shunt to the Dynon. These wires will turn into glowing fire making dragons if they are ever shorted out!!!!
My shunt was on the engine side of the firewall...The rubber boots on the wires covered the screw part of the connections..I plan on putting some liquid tape on the shunt part and the other areas that are electrified.....have not got around to that yet. Not much that can come into contact with my shunt unless I have other big problems. Since I do not work on the engine most of the time with the master on, there is little risk of dropping a wrench or other tool on there.
How the heck you gonna get to them fuse blocks after that top skin is riveted on?
Also, I recommend fusible links close to the shunt on the wires going from the shunt to the Dynon. These wires will turn into glowing fire making dragons if they are ever shorted out!!!!
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Brantel
Well Known Member
az_gila
Well Known Member
But... Murphy always...
...drops the screwdriver at the wrong time, even when the brain is engaged....
I recommend the little flap of baffle material to stop gravity aided stuff from touching any part of the shunts. Cheap and easy.
...drops the screwdriver at the wrong time, even when the brain is engaged....
I recommend the little flap of baffle material to stop gravity aided stuff from touching any part of the shunts. Cheap and easy.
Brantel
Well Known Member
First step is to not work on the engine with the master turned on.....I can't think of many if any reasons to do this.
...drops the screwdriver at the wrong time, even when the brain is engaged....
I recommend the little flap of baffle material to stop gravity aided stuff from touching any part of the shunts. Cheap and easy.
hydroguy2
Well Known Member
...drops the screwdriver at the wrong time, even when the brain is engaged....
I recommend the little flap of baffle material to stop gravity aided stuff from touching any part of the shunts. Cheap and easy.
Noted. My wires from the battery to the Master are booted for protection. The ANL and Shunt could only be hot when the Master is pulled in and/or the Alt is running. So this is a risk I'm willing to accept due to the amount of time danger is truly imminent.
ps, I work in electrical cabinets often that have exposed 125VDC and some 480VAC circuits. I've seen what a fireball can do.
Canadian_JOY
Well Known Member
Ummm... there's something in Don's pics (N8RV) that's worthy of mention from a safey perspective. I hope this comment will be received as positively as its writer intends...
The two sense wires coming off the shunt to provide +/- deflection to the ammeter are twisted orange wires. If you think about it, they're connected to a pretty huge current source, be it the alternator or battery, depending how you've wired your airplane. The wires in the picture don't appear to have any short circuit protection on them. Since they're tied to aircraft power if they happen to chafe and short to ground you've got lots of smoke and maybe even some very undersireable localized heating in the vicinity of the short.
If I may be so bold as to suggest it, ammeter sense wires should have short-circuit protection on them, as close to the shunt as possible. In my aircraft I've just used a pair of in-line automotive-style fuse holders. Yes, it's not a very clean solution but it's a heck of a lot better than having a dead short with no protection for the wire. If you've ever had a wire go up in smoke in a cockpit you'll know why protecting those wires is of vital importance.
BTW, my ammeter shunt itself isn't insulated because I've stuck it in a location where it's almost impossible to get a metal tool near it. All the same, I keep thinking I should fabricate a nice cover like the one in Don's pics, just for added protection.
The two sense wires coming off the shunt to provide +/- deflection to the ammeter are twisted orange wires. If you think about it, they're connected to a pretty huge current source, be it the alternator or battery, depending how you've wired your airplane. The wires in the picture don't appear to have any short circuit protection on them. Since they're tied to aircraft power if they happen to chafe and short to ground you've got lots of smoke and maybe even some very undersireable localized heating in the vicinity of the short.
If I may be so bold as to suggest it, ammeter sense wires should have short-circuit protection on them, as close to the shunt as possible. In my aircraft I've just used a pair of in-line automotive-style fuse holders. Yes, it's not a very clean solution but it's a heck of a lot better than having a dead short with no protection for the wire. If you've ever had a wire go up in smoke in a cockpit you'll know why protecting those wires is of vital importance.
BTW, my ammeter shunt itself isn't insulated because I've stuck it in a location where it's almost impossible to get a metal tool near it. All the same, I keep thinking I should fabricate a nice cover like the one in Don's pics, just for added protection.
N8RV
Well Known Member
Yeah, I think that's what Brian was suggesting with the fusible links. I'm sure that's a great suggestion, and I appreciate you both for pointing out that possible safety concern.
This is one area (of many) where I had no guidance and just wired per the instructions. A good dose of common sense goes a long way when it's possessed. Unfortunately, I'm a few marbles short of a full jar in that capacity.
Thanks for the heads-up, guys. Now I need to see what size fuses would be required ...
EDITED:
I went back to the installation instructions and found the following:
"We highly recommend that you fuse both the connections between the shunt and the EMS-D120. There are two methods for accomplishing this. You may simply connect two 1 amp fuses in-line between the shunt and the EMS-D120. Or, you may use butt splices to connect 1” to 2” sections of 26 AWG wire between the shunt and each of the Amps leads connecting to the EMS-D120. These fusible links are a simple and cost-effective way to protect against short-circuits."
Guess that answers it. BIG thanks for pointing this out!
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