rvtach
Joined: 28 Jan 2008 Posts: 26 Location: Tucson, AZ
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Posted: Thu Aug 27, 2020 6:42 pm Post subject: Z13-8 main alternator troubleshooting |
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Hello expert electron herders-
I'm just finishing the phase one flight test on my O-360 powered RV-7A wired per Z13-8 and I'm trying to troubleshoot a main alternator problem which is that the alternator isn't putting out any voltage. I replaced the voltage regulator (at less than $20 it seemed like a reasonable first step) and still no power from the B&C 60 amp alternator.
Due to some poor planning on my part the VR is in a somewhat inaccessible location which may have contributed to me hooking up the IASF leads on the replacement VR incorrectly- I connected the "S" lead (which is jumpered to the "A" lead) to the "I" tab. Wonder if that may have fried the voltage regulator?
At the hangar today I took some measurements and here's what I found:
Good continuity from the main bus, through the D/C power master switch to the VR-166 voltage regulator A/S terminal. 0.5 ohms.
Good continuity from the VR to the Alternator Field plug. 0 ohms.
Good continuity from the VR case to Firewall forest of tabs ground. 0 ohms.
With Master switch on and battery voltage at 12.5V there is no voltage at the alternator field plug. It seems like there should be something on the order of 12V at the field plug, no?
Any suggestions before I just go out and buy a new VR-166?
A final note- I truly appreciate all the information I've gleaned from this forum over the past 10+ years. Because of everything I've learned from Bob and all the rest of you guys this is the only electrical problem I've had- everything else has been perfect. Beyond my hopes!!
Cheers-
Jim
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_________________ Jim McChesney
Tucson, AZ
RV-7A Flying |
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