Ed Anderson
Joined: 10 Jan 2006
Posts: 475
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 Posted: Fri May 11, 2012 3:03 pm Post subject: Engaged Starter? Re: Engine Quit |
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Jim, one thing you don't want to overlook. Check the next time you run the engine that the starter is not engaging the flywheel. I have heard (don't know how valid) that a engaged/stuck starter can act as a generator. I would presume the starter/flywheel might show some physical evidence if that occurred. I know pretty long shot - but, wouldn't hurt to check.
The Pmags have an internal generator that can easily produce 20 volts - however, I am certain it could not sustain 60 amps - probably no more than 3-4 amps. In any case, there is a diode in the Pmag that should prevent your aircraft system from ever seeing the Pmag internally generator voltage.
Check your Pmag manual for more information.
Ed
Edward L. Anderson
Anderson Electronic Enterprises LLC
305 Reefton Road
Weddington, NC 28104
http://www.andersonee.com
http://www.eicommander.com
From: Jim Thorne (rv7a(at)cox.net)
Sent: Friday, May 11, 2012 5:58 PM
To: rv-list(at)matronics.com (rv-list(at)matronics.com)
Subject: Engine Quit
OK I need some help on where to start looking. Sorry for a long post but don’t know how to say it without leaving important stuff out. About a month ago I lost power on takeoff. It didn’t quit completely so thanks to some throttle blips and altitude I made the “impossible turn” and got the plane back on the ground and taxied normally to the hangar.
First we checked the fuel system, doing fuel flows every conceivable way we knew how. Even tied the tail down and ran one in a “climb out attitude”. All flows seemed to be normal.
The next thing was to download the Dynon data log. In looking that over it became apparent at the time of the incident I was producing 62 Amps and 20+ Volts. This would last for a few seconds and drop to a more normal range then spike again it did it several times. It appeared that the spikes were when the engine wasn’t running.
The next was checking the P and E mags. Brad, at E-Mag, after hearing my story suggested I send them in. They found the circuit board in the P-Mag wasn’t reliable. Both mags had been subjected to very high temps, according to Brad this could have been from the engine oil temp or the high amperage. I learned that I had the blast tubes aimed incorrectly. They have been rebuilt and are now both P-Mags.
The alternator, Van’s Nippon Denso, was bench checked twice by two separate shops. Everything was normal.
The plane was reassembled and test run. Everything seemed normal until I ran high RPM, 2000+. As soon as the RPMs climbed the Dynon showed the amps climbed right up to 60 and voltage up to 20. The engine kept running on the ground but to say the least I am not enthusiastic trying to fly it with these same conditions.
Where do I go from here?
Jim Thorne
RV7A
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_________________
Ed Anderson
Rv-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com |
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