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Eratic Tach
I have a CH750 with a Jabiru 3300 Gen 2. The Engine has around 220 hours on it. Runs great. I am running a Dynon D180. The issue I am having is when the engine is at idle the tach goes to zero. The tach reads once the RPM's get to 1000. When flying and i reduce the power the tach goes eratic? Looking to see if anyone else has had this problem.
Replies to This Discussion
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Permalink Reply by John Austin on
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What is the pickup sensor for the tach? Does it get pulses off the AC alternator output? The Gen 2's don't produce charging current at 1000 rpm - don't know if that's related to your problem?
I did not have a Dynon (had a MGL Xtreme Efis) and it picked up the alternator pulses but it was somewhat erratic. My ultimate solution was to install a Honeywell GT-1 Hall-effect sensor which has proven to be rock-solid for years. Here's the write up: Honeywell GT-1 . If you read the entire post, someone responded that they did the same installation with a Dynon 180 and it worked great!
A caution: The genuine Honeywell GT-1 was a mil--spec product with high temperature ratings (150C/302F). It is no longer in production, but they used to occasionally show up on Ebay, etc. There's a zillion cheap Chinese "GT-1's" available and they're super-cheap, but also super unreliable. I wouldn't use anything but a sensor that has a spec for its temperature rating - the cheap ones will work great until the temp gets up under the cowl, then they'll go erratic. Probably a discussion with a tech at a reputable electronics parts supplier could find you an affordable substitute with the higher temp rating.
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Permalink Reply by Bobby Egger on
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Great thank you for the info. I will for sure look into this.
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Hi bobby, john,
We have a waiex with a jab3300. john is right the power pulse off one side of charging circuit may be erratic weak below 1000 rpm. Rotec aerosports sells a tach reader , similar to what john described, hall effect. Mounts on back side of engine on the spyder. gets pulses from the magnets on flywheel.
See. www.rotecaerosports.com look under jabiru accessories. you can hook it up to a efis or vdo guage.
cheers,
michael.
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Thank you for the response i will look into this for sure.
Thank you,
Bobby
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Permalink Reply by Adel Bazzi on
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Hi Bobby,
Not sure if you’ve talked to Nick from Arion about this, but I was having issues with my Gen 2 not charging until I got to at least 1800-2000 RPM, and he suggested that I re-wired my stator, which I did, and I now generate more than enough charge starting at about 900 RPM. I am going to try to upload the file/instructions that Nick sent me. Hope this helps.
Blue Skies!
Adel Bazzi
- Attachments:
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Stator rewind.pdf, 466 KB
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Awesome. Thank you for this. I will check this for sure.
Thank you,
Bobby
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By the way, I just noticed that I said Gen 2. Mine is a Gen 1, so make sure that this applies to you as well.
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Permalink Reply by jerry nichols on
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I have the same setup on a gen 3. My RPM doesn't start reading until 6-700 RPM but is steady inflight.. Sorry I can't provide a solution but maybe this info will help
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So my plane does not have an external alternator. It has the factory switches which has the alternator switch right next to the master switch. When I assumed that the alternator switch had to be on. When i shut that switch off the tach reads perfectly fine. When i turn it on it goes all over? Does anybody have any experience with this? This is my first Jabiru. Any help would be greatly appreciated.
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