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1. 09:39 AM - Re: Re: B&C alternator conversion in Canada (Bitterlich, Mark G CIV NAVAIR, WD)
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| Subject: | Re: B&C alternator conversion in Canada |
All: I love the B&C company, and the owner is just a great guy!
That said, I do not recommend the small 10 amp PMG generator for anyone other than
those wanting to save every last ounce of weight, usually for aerobatic purposes.
Most Yak, CJ, and Sukhoi owners run two 12 volt gel cells in series. The ones
that come with the PMG mentioned above are very small. Over time these will
slowly degrade. What typically happens then is that with a large current draw
of any type, it will short out the voltage regulator and allow unregulated voltage
to increase with engine RPM. The kit includes an over-voltage protection
kit, which is basically a crow-bar circuit that causes a direct short, which
in turn pops a circuit breaker, which in turn allows a relay to open, thus removing
the Alternator/PMG output to the aircrafts electrical bus. This is a
very simple over-voltage protection circuit, but the down side of is that "it
takes time to work". Meaning, that you can still have unregulated voltage on
the main aircraft bus long enough to cause extensive avionics damage. The solution
is very simple.... keep your batteries in perfect condition and this will
rarely..... if ever ...... occur. Having repaired three aircraft that ignored
this advice, I can tell you with firm confidence that if you let the batteries
degrade with this design, it WILL happen.
All of the Russian electrical designs for these aircraft (Yak/Sukhoi) are ALMOST
identical. The layout of where the parts happen to end up is different, but
the design is the same. If you still have questions about it, let me know and
I would be glad to help. I have pictures of the main electrical panel of the
55 SOMEWHERE on my computer. :-( I lose things in the vast warehouse of
the hard drive all the time. :-)
In short, the 10 amp B&C is a product directed at a very specific market, and is
not a good choice for anyone outside of that sphere.
As Jan mentioned, the SK35 with the LS-1A regulator is a much better choice for
the majority of folks flying Yaks, Sukes, or CJ's. It is a true alternator
with a Field Winding, and is more robust for the majority of needs. If you have
a ton of electrical additions, then the SK55 of course.
Mark
-----Original Message-----
From: owner-yak-list-server@matronics.com [mailto:owner-yak-list-server@matronics.com] On Behalf Of Jan Mevis
Sent: Monday, March 03, 2014 2:03 AM
Subject: Re: Yak-List: Re: B&C alternator conversion in Canada
I had the permanent magnet 10 amp B&C some years ago.
One day, the overvoltage protection AND the regulator were severely damaged, because
too large a current was drawn.
I replaced it with the more robust 35 amp type.
The 35 amp type is just slightly heavier than the 10 amp, but has a much better
voltage regulating system.
Jan
On 03/03/14 04:36, "milescrane" <milescrane@gmail.com> wrote:
>
>We installed a B&C alternator on our Yak 55 (the one marketed for the
>Sukhoi) and did save about 25lb. This is the low output, permanent
>magnet type.
>It came with a solid state regulator and overvoltage protection. The
>weight saving came primarily from the removal of the generator, and
>also from the old carbon pile regulator and relay box.
>
>The positives so far are: improved power-to-weight ratio and aerobatic
>performance, and a smoothly operating charging system that works well
>even at low engine speeds.
> As for the negatives, we found that it was difficult and confusing to
>sort out the existing wiring in our -55, for which we could find no
>diagrams, although everyone we talked to said it was 'easy'. We routed
>the wires as much as possible with the existing bundles and removed
>wires which we identified as being non-functional. We traced one fault
>after the install to an original wire to a CB on the panel, that
>appeared intact but had failed internally- due to flexing, we think.
>The wiring turned out to be a greater challenge than it should have been.
>A few maintenance professionals were scratching their heads along with us.
>
>I would recommend conferring with Transport Canada M&M first. They will
>likely require documentation of all phases of the installation
>including the suitability of the physical mounting of the alternator
>and regulator, gauges and support of the wiring, etc.
>
>If we were not flying contest aerobatics, we would have left the
>generator in. Now that the alternator is in, we are happy with how it
>is performing.
>
>
>Read this topic online here:
>
>http://forums.matronics.com/viewtopic.php?p=419687#419687
>
>
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