Garrett Gee Posted March 10 Report Share Posted March 10 Due to the less than stellar electrical system (fine for VFR/analog, less so for an IFR platform) and the fact that I recently had a stator fail, I am working on an electrical system redesign/rewire. While working on how I want to redesign it, I made the observation that the starter solenoid is connected to the battery and the output is directly connected to the starter. Makes sense. But, then I got to thinking, if the solenoid were to stick (I have seen this happen twice in our training fleet, one was a starter solenoid, the other a master), there is NO way to remove power from the starter solenoid. There is no inline slow blow fuse, no master contactor, nothing. And you obviously can't remove the cowling to disconnect the battery. So do you just let the wire overheat/burn, the battery to die, or the starter blow itself apart? All three options are less than ideal. Has anyone ever experienced a stuck solenoid on a CT? I am going to most likely install a slow blow fuse and keep spares in the airplane, but curious if this is the norm in light sport airplane? Has anyone installed a master contactor before? I don't like the power draw of them when on, as many of the ones I see are .8-1 amp, which is a lot considering the capacity of the overall system. Just an observation I noticed and was curious. Quote Link to comment Share on other sites More sharing options...
Madhatter Posted March 10 Report Share Posted March 10 I suppose you could put in a disconnect switch like you find on boats. Maybe it would be easier to replace the solenoid every so often. Quote Link to comment Share on other sites More sharing options...
Madhatter Posted March 10 Report Share Posted March 10 You can buy an aircraft quality starter solenoid from aircraft spruce. I don't know the quality of the one that comes on the CT, many light sport items seem to be on the cheap side. Quote Link to comment Share on other sites More sharing options...
Garrett Gee Posted March 10 Author Report Share Posted March 10 5 minutes ago, Madhatter said: You can buy an aircraft quality starter solenoid from aircraft spruce. I don't know the quality of the one that comes on the CT, many light sport items seem to be on the cheap side. I was thinking that. I haven't had any issues with mine (knock on wood), just an observation about the issue that could occur. I am looking at a slow blow fuse right now. Found a couple that would blow after approximately 15 seconds based on the spec sheet. Quote Link to comment Share on other sites More sharing options...
Madhatter Posted March 10 Report Share Posted March 10 17 minutes ago, Garrett Gee said: I was thinking that. I haven't had any issues with mine (knock on wood), just an observation about the issue that could occur. I am looking at a slow blow fuse right now. Found a couple that would blow after approximately 15 seconds based on the spec sheet. The amperage is very high on the starter activation and I'm sure it can vary depending on temperature causing higher friction especially in cold temperatures. I think a fuse would become an issue. Quote Link to comment Share on other sites More sharing options...
Tom Baker Posted March 10 Report Share Posted March 10 The solenoid is supplied by Rotax, not that it makes any difference. I have never seen on fail, but I suppose it could happen. I do see some airplanes with a power shut off in the supply line, the Savanah and Aeroprakt come to mind. Quote Link to comment Share on other sites More sharing options...
Garrett Gee Posted March 10 Author Report Share Posted March 10 19 minutes ago, Tom Baker said: The solenoid is supplied by Rotax, not that it makes any difference. I have never seen on fail, but I suppose it could happen. I do see some airplanes with a power shut off in the supply line, the Savanah and Aeroprakt come to mind. That is reassuring that someone working on them more often hasn't seen one fail. Thank you. Quote Link to comment Share on other sites More sharing options...
FredG Posted March 10 Report Share Posted March 10 Anybody know how many amps the starter draws? Also, once the engine starts, if the starter is still running due to a stuck solenoid, do you know only because the system voltage is low? I would thing it would be hard to hear it once the engine is running. Quote Link to comment Share on other sites More sharing options...
Garrett Gee Posted March 10 Author Report Share Posted March 10 9 minutes ago, FredG said: Anybody know how many amps does the starter draws? Also, once the engine starts, if the starter is still running due to a stuck solenoid, do you know only because the system voltage is low? I would thing it would be hard to hear it once the engine is running. Rotax specifies 300 amps for 1 second (in-rush) and 75 amps continuous Quote Link to comment Share on other sites More sharing options...
Tom Baker Posted March 10 Report Share Posted March 10 I have seen ignition switches stick on the CT, and yes the voltage does get low fast. Quote Link to comment Share on other sites More sharing options...
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