Tachometer Sensor

[ibelmore]

I am getting RPM fluctuations with my Vans cable driven tachometer sender so I would like to use a hall effect sensor on my Bendix Magneto.  Would the Garmin  G3X sensor work with the D120?  Are there any others I could consider.

Ian Belmore
RV-7 almost ready to fly

 

[dynonsupport]

First, we'd primarily recommend that you use the magneto p-lead through the 30K resistors as the manual instructs, unless you've already tried that. When hooked up this way, there's no possibility of the EMS grounding affecting your mags, which is the primary concern here.

To answer your question - we're not familiar with the G3X sensor, but if it's ultimately outputting a DC voltage frequency with pulses above 2V on the high side, and back down to near ground, it'll work with SkyView.

 

[ibelmore]

My concern about using the p lead is the loss of tacho indication until the system changes to the secondary pickup (lightspeed plasma 3) when doing a mag check. Not a major problem but still not the perfect solution.  This was the reason for installing the cable driven sensor.

I will order a Garmin magneto sensor and report back.

ps it is a D120 not skyview system that I have, hope that doesn't change your answer.

 

[dynonsupport]

That switchover is within a second or two when you switch between mags. You'll usually see a momentary blip, but by the time your engine speed has actually dropped 50ish rpm, it's basically reading again.

On SkyView, it's near instant.

 

[ibelmore]

I can confirm the UMA/Garmin hall effect sensor in the Magneto works very well with the D120.

Ian