Garrett Gee Posted February 13 Report Share Posted February 13 Looking for thoughts/opinions. Had the generator give up on me today right after takeoff. Got the airplane to my mechanics airport (earth-x battery for the win) and we are working on troubleshooting before pulling the engine. Steps so far: Disconnected AVC-1 regulator connector and checked for AC voltage with the engine running on the two yellow wires. Nothing (0 volts), not even a wiggle. Checked for power on the appropriate control wires and had battery voltage where expected. Regulator turns on the gen lamp fine. Everything is currently pointing to the stator at this point. My mechanic has done Rotax training, but it has been a little while, so we are trying everything we can to see what else could possibly be wrong. Did the resistance check on the yellow leads and got .2-.3 ohms, and also checked from each yellow wire to ground and all read "infinite' ohms. Are there any connectors on the back of the stator I am missing or can't easily see? The ignition coils and RPM all seem to be working correctly. Any thoughts, or is this stator likely shot. I thought it was unlikely/unusual for these to fail? Side note: Has anyone here put an external alternator on the Rotax in a CTLS? Does it require a cowling modification? Thanks, Garrett Gee Quote Link to comment Share on other sites More sharing options...
Madhatter Posted February 13 Report Share Posted February 13 https://pointsforpilots.blogspot.com/2012/12/testing-rotax-912914-generator-and.html Quote Link to comment Share on other sites More sharing options...
Garrett Gee Posted February 14 Author Report Share Posted February 14 1 hour ago, Madhatter said: https://pointsforpilots.blogspot.com/2012/12/testing-rotax-912914-generator-and.html Thank Madhatter. I ran across that article a couple of years ago while trying to learn more about how the system worked and that is what I based my original tests on funny enough. Based on that, I am pretty sure the stator is shot. Going to do some more digging before we pull the engine off the frame, but it looks like its dead. Might see about an external alternator, given the stator is around $1,100. I can do a whole Rotax alternator setup for (relatively speaking) not much more and I think it might actually be easier, assuming the cowling doesn't have to be modified. Quote Link to comment Share on other sites More sharing options...
Roger Lee Posted February 14 Report Share Posted February 14 The external generator will not fit under a CT cowling and the pulley up front for the belt won't work either. Quote Link to comment Share on other sites More sharing options...
Garrett Gee Posted February 14 Author Report Share Posted February 14 13 minutes ago, Roger Lee said: The external generator will not fit under a CT cowling and the pulley up front for the belt won't work either. Good to know. That is kind of what I figured. Time to go pull the stator... Quote Link to comment Share on other sites More sharing options...
Jim Meade Posted February 14 Report Share Posted February 14 I put a 40A alternator on my 2007 CTSW several years ago. Got the parts from Leading Edge Air Foils. Pulley bolts on the hub and works fine. I had to modify the cowl. Quote Link to comment Share on other sites More sharing options...
Garrett Gee Posted February 16 Author Report Share Posted February 16 On 2/14/2024 at 6:30 PM, Jim Meade said: I put a 40A alternator on my 2007 CTSW several years ago. Got the parts from Leading Edge Air Foils. Pulley bolts on the hub and works fine. I had to modify the cowl. I really like that. Would love to get to play with some composite work, but I don’t wanna learn on my cowling. That does look really good though! Quote Link to comment Share on other sites More sharing options...
FredG Posted February 16 Report Share Posted February 16 I have no experience, but this looks interesting: https://stolcreek.com/alternator Quote Link to comment Share on other sites More sharing options...
Garrett Gee Posted February 16 Author Report Share Posted February 16 1 hour ago, FredG said: I have no experience, but this looks interesting: https://stolcreek.com/alternator Interesting! Quote Link to comment Share on other sites More sharing options...
stratotramp Posted June 6 Report Share Posted June 6 Hiya, with the capacitor how important are the tolerance figures? This is the cap in the blog post above, States tolerance: -10%+75%: DCMX223U025AD2B Cornell Dubilier (CDE) capacitor 22,000uF 25V Aluminum Electrolytic Large Can Computer Grade 2020063134 (tedss.com) I am probably going to replace Generator & have this capacitor: -20%+20% KEMET 22000μF Aluminium Electrolytic Capacitor 25V dc, Stud Mount - PEH200HC5220MB2 | RS (rs-online.com) I would assume negative % more important than +ve percent (surely if you need more u-farads you would spec higher u-farad device?). Context: I managed to have a full electric out with my first passenger the other day (No Altimeter, VSI, Engine Revs, Temps, Intercom, Radio, Transponder, Flaps, Nav). Did my first flapless landing here (Sackville Farm, Riseley) the other day. I am at 72 hours experience (3/5ths on type). It is massive 700m but very bumpy! (this is a previous video - unfortunately no debrief video of the actual event!) Ok, not an engine out but scary for a sub 100 hour pilot - My passenger said i was very professional. Won't get a chance to properly investigate for 2 weeks, There is a strong possibility it is my own fault, perhaps disturbed something with starter motor swap 3 weeks back. Though I did 2 hours of flight testing since (before taking Px) and V seemed ok! For you history buffs (particularly with WW2 D-Day celebrations/remembrance - appreciate you Yanks! Deep respect to your fathers & grandfathers who helped us out (and mothers / grandmothers in the factories!)): Riseley in World War 2 During World War 2 Riseley was used by the USAAF as a base to store and fill bombs which were then forwarded to local American air bases. A large camp was set up at the top of the Carriage Drive to Melchbourne House to house the troops. The camp included a cinema. The American airmen stationed in Riseley Camp occasionally held parties for local children and there are still residents living in Riseley who can recall attending the children’s parties on the camp. In October 1943 a B17 Flying Fortress aircraft returning from a bombing raid in Germany, crashed in a cottage garden at the north end of the High Street. The crew had bailed out before the crash. The plane having been seriously damaged by a German fighter aircraft on its return from Germany. During the war, a British fighter plane also crashed when it ran out of fuel at the bottom end of the village. The crew bailed out safely and no-one was harmed in the incident. A Brief History – Riseley Village Not too far from here: RAF Chelveston - Wikipedia - (this is now the big solar farm to the north of Riseley) and here: RAF Glatton - Wikipedia Quote Link to comment Share on other sites More sharing options...
Anticept Posted June 6 Report Share Posted June 6 Get ALS40A104KF025 the rotax install manual recommends 22000 uF MINIMUM and suggest larger. The capacitor part number I provided is 100,000 uF and has a ripple current rating of 29 amps, more than enough to absorb surging if the battery were to disconnect while the alternator is running and not explode like a 22,000 will. Larger caps also have a much better noise filtering capability. The regulators are noisy Quote Link to comment Share on other sites More sharing options...
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