alec(at)alecmyers.com
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 Posted: Thu Jun 09, 2016 7:05 pm Post subject: Saggy bus voltage on Cessna 182 |
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Oops... my bad. The breaker resistance is 2 milliohms (measured on the bench at 3) but the voltage drop calculation is correct - 150mV. Plus another 2 milliohm for 3 feet of 8ga wire from the B terminal to the bus, so that's another 150mV drop. That's about half the voltage loss accounted for.
On Jun 9, 2016, at 22:56, Alec Myers <alec(at)alecmyers.com (alec(at)alecmyers.com)> wrote:
Tyco quote a resistance of 20mOhms for their 50A breaker. I just put the new 60A (not Tyco) breaker on the bench for a four terminal resistance check, and measure about 30mOhms - at 50A that's a 0.15 volt drop (and 7 watts of heat, which should warm it up). I'm seeing not much more than that on the existing installed original breaker, so I'm not sure how much better the new breaker will be.
On Jun 9, 2016, at 22:32, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:
At 10:29 PM 6/8/2016, you wrote:
| Quote: | | There is an adjustment inside the regulator. The newer regulator has the lid riveted on, but the older one (same part code) has the lid secured by screws, so the trim pot can be reached. Set to maximum, I now get a bus voltage of 14.2V under no load, and 13.8 with everything energized. Which is a big improvement. |
But still too low . . . it shouldn't sag
that much under load.
Bob . . .
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