Garmin G3X magnetometer fail with aeroleds strobe on

Hi folks,

I have been trying to pass the magnetometer test but always fail when aeroleds strobes are on, lights are installed per aeroleds instruction, wires grounded at both ends, tomorrow I will try to install a capacitor, next will be re routing wires

No problems with anything else, even nav light that run from same wires.
Any ideas???

DJR said:

hi Fernando,
I had the same Problem. I wouldn't spend too much effort to correct the problem at this point. I talked with Christer at Stein Air and here is his advise. just try the calibration test in a different location and do the test with the strobes on. if it still does not pass turn the strobes off and do the test again. After I did so, the test passed and then I noted the variation of the mag heading change during normal ops after turning on the strobes. The change was very minimal and was not an issue. We're talking maybe a degree or two. Simply put, the variation is not a concern. If you get a huge swing, then I would start making some changes, but you probably won't need to.
Anyway, this was my experience.

DJR

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Thanks for advice!!!

Fernando,
Had the same kind of problem but with standard Nav light in tail.
When I tried it again with a Whelen LED Nav/ strobe the test passed.
The variation with the Nav light was 2 degrees so we just left it alone and the future fix will be to switch to LED's. Maybe the Whelen lights were drawing less amps than the AeroLed's.

Where is the magnetometer located? If it is in the tail, then the Suntail strobe may be the culprit.

You could try connecting the Suntail chassis and black ground wire to the shield only and not ground to structure at the tail. That will force all of the ground current to flow in the shield, which will help to neutralize the magnetic field since the return current will be flowing around the outbound current, making equal and opposite magnetic fields which will help to neutralize them.

Dean Wilkinson
CTO, AeroLEDs LLC

Dean_aeroleds said:

Where is the magnetometer located? If it is in the tail, then the Suntail strobe may be the culprit.

You could try connecting the Suntail chassis and black ground wire to the shield only and not ground to structure at the tail. That will force all of the ground current to flow in the shield, which will help to neutralize the magnetic field since the return current will be flowing around the outbound current, making equal and opposite magnetic fields which will help to neutralize them.

Dean Wilkinson
CTO, AeroLEDs LLC

Click to expand...

Hi Dean,

Yes magnetometer is at the rear fuselage, so today I am going to make some mores test. Actually Suntail is installed exactly per your instruction twisted shielded wire grounded at both end and Suntail chassis and groun power grounded at the tail, so I will disconnect ground at tail and will let ground flow by the shield.

One question Dean, do you think a Capacitor will make any help???

Thanks for answer

Fernando

Fernando,

I don't think a capacitor will help because it is the low frequency current flow that is creating the bulk of the magnetic field that is affecting the magnetometer. If the bulk current is flowing in structure separate from the power wires, then you will get a sizeable magnetic field that will affect the magnetometer. Forcing the ground current to stay against the power wires will collapse the field and contain it close to the wires so it won't reach the magnetometer.

Dean

AirbusPilot said:

Hi Dean,

Yes magnetometer is at the rear fuselage, so today I am going to make some mores test. Actually Suntail is installed exactly per your instruction twisted shielded wire grounded at both end and Suntail chassis and groun power grounded at the tail, so I will disconnect ground at tail and will let ground flow by the shield.

One question Dean, do you think a Capacitor will make any help???

Thanks for answer

Fernando

Click to expand...

Test passed!!!

Dean_aeroleds said:

Fernando,

I don't think a capacitor will help because it is the low frequency current flow that is creating the bulk of the magnetic field that is affecting the magnetometer. If the bulk current is flowing in structure separate from the power wires, then you will get a sizeable magnetic field that will affect the magnetometer. Forcing the ground current to stay against the power wires will collapse the field and contain it close to the wires so it won't reach the magnetometer.

Dean

Click to expand...

I just did what you said and now strobe light is almost invisible for magnetometer, test passed

Thank you Dean

Dean_aeroleds said:

You could try connecting the Suntail chassis and black ground wire to the shield only and not ground to structure at the tail. That will force all of the ground current to flow in the shield, which will help to neutralize the magnetic field since the return current will be flowing around the outbound current, making equal and opposite magnetic fields which will help to neutralize them.

Click to expand...

I would certainly advise taking the time to make sure the magnetic interference test passes, rather than proceeding with a known bad magnetometer installation. The above advice is a good place to start. We often see problems with magnetometer installations where a light or other device has been installed in such a way that it uses the airframe as a ground return. Quite often, the solution in these cases is to remove the ground connection to the airframe and run a separate ground wire, or use the shield for the ground as described here. Otherwise, currents flowing in the airframe will generate unwanted magnetic fields that can affect the magnetometer.

thanks,
- Matt

With the new G3X equipment on its way, I am looking at the wires I strung through my wings a long time ago and trying to figure out how to best accomodate a magnetometer in the wingtip. I will add a ground return. Should I worry about running magnetometer wires in the same conduit with strobe wires?

aturner said:

With the new G3X equipment on its way, I am looking at the wires I strung through my wings a long time ago and trying to figure out how to best accomodate a magnetometer in the wingtip. I will add a ground return. Should I worry about running magnetometer wires in the same conduit with strobe wires?

Click to expand...

Hello Andy,

In the G3X system, the wires carrying data between the magnetometer and AHRS are digital, so I wouldn't worry too much about bundling them with a shielded strobe cable. You can use shielded wire for the magnetometer as well if you like. The main thing is to avoid magnetic disturbances near the site of the magnetometer itself. The GMU 22/44 section of the G3X installation manual has some tips on how to achieve this.

thanks,
- Matt

Magnetometer test passed, now aeroleds strobe make autopilot servos buzz

Hi Folk,

After follow Dean from Aeroleds recommendation Magnetometer test is passed with flying colors so I decide to try to find if Aeroleds Strobe has problem with other equipment and I start testing, I don't have noise on intercoms or communication so great, but I turned on Trutrak Autopilot and servos start buzzing at strobe light rhythm. Yesterday I was trying to fix the problem all day trying everything, till I found that the problem could be the diode bridge from B&C that connect my Main Buss with endurance buss, every time that I turn on Endurance Buss alternate feeding, servos stop buzzing, after that I tried connect main buzz with endurance buss directly without diode and also that fix the problem. For some reason the diode that connect main buss with endurance buss is amplifying noise from strobe light, anyone has experience this kind of problem?, any ideas on how to fix it?

Cheers,