Amperage doesn’t go up past the alternator rating…Voltage spikes so it
kills your electro-whizzies but will not pop a breaker or fuse.
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Jeff Luckey
Sent: Tuesday, September 01, 2009
12:33 AM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: More
Charging Circuit Info
What about the circuit breaker in the
alternator output? In the case of a full-field regulator failure, you
simply open the circuit breaker (if it doesn’t do it on its own due to the fact
that it’s charging current will go to max)
With the circuit breaker open nothing gets
fried or boiled. (sounds like a cooking show;)
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Kelly Troyer
Sent: Sunday, August 30, 2009
22:19
To: Rotary
motors in aircraft
Subject: [FlyRotary] More Charging
Circuit Info
Great cooling numbers on
your flight testing...........Good to hear that after all the trials and
tribulations you have been through that you are gaining confidence in your
installation..............
The electrical system info may be
somewhat dated as you said so everyone has to evaluate for themselves if
current equipment failure rates are within their personal
tolerance limits..........Most of us
are dealing with 1986-1995 era alternators with unknown mileage/hours
on them..........I have had
failures on these alternators in automobiles............Some
times just the diode array but once the internal
regulator............As luck would have it the failure was an
"Open" that time so did not have a runaway
voltage condition..............So as I said each of us has to make
their own decision on this subject.............
If nothing else this link provides a very
comprehensive explanation of the charging system and excellent
troubleshooting information for even the most electrically challenged
of our little group.............IMHO
Kelly Troyer
"Dyke Delta"_13B ROTARY Engine
"RWS"_RD1C/EC2/EM2
"Mistral"_Backplate/Oil Manifold
-------------- Original message from "Mike Wills"
<rv-4mike@cox.net>: --------------
Thanks for the link. Some interesting info, but...
What is lacking is any sort of statistical info to indicate that this is a real
problem. I'm not convinced that using a Cherokee as an example system is all
that applicable. And I dont know how old this article is, but gather it is
pretty old given the reference to problems with alternator failures in cars
resulting in nothing more than burning out lights. I'd venture to say that for
virtually any car built since the mid 80s, a runaway alternator output would
result in far more than a few burnt out lights.
Since virtually all cars these days use internal solid
state regulators, if these things were prone to failure, and since a runway
over volt failure on any modern car would likely toast some pretty expensive
electronics, I'd expect a fair number of really expensive repairs, warranty
issues, etc.... My conclusion is that this type of failure is actually quite
rare, but if you can point to relevant statistical data that says
otherwise, I'm all ears.
Some folks are more risk averse than others and a 1 in
a million possibility is enough to justify making a change. But sooner or
later you have to stop engineering for every possible risk no matter how remote
the failure mode and just get on with it.
Meanwhile, the important points I take from this
reference are, dont overload your alternator, ensure that the field is
de-energized while cranking the engine, and keep it cool.
Off topic, another 1.2 hours closer to completing my
Phase 1. This was the first flight that after I landed I didnt have anything on
my list to fix before the next flight. 95 degrees OAT at takeoff today and
the oil temp got to 200 at the top of the climb to 5000' but backed off to 192
after I leveled. H2O temp never above 180. Starting to gain some confidence in
it. Oh, and I have a DNA muffler on order. Should have it by next weekend but
may put off installing it so I can fly some more.
----- Original Message -----
Sent: Sunday, August 30,
2009 1:21 PM
Subject: [FlyRotary] FW:
More Charging Circuit Info
I am still on the bandwagon about
modifying our flying alternators for an external
regulator as noted in my past posts...........After supplying group
member Tim Holt &
also the group with info how to modify the Mazda alternator I
remembered the link
below which explains in language even the electrically challenged among
us will be
able to understand...............This info may have been already seen
by some of you
but I believe all of us should file it and also copy it to have
available when wiring
our aircraft electrical systems.............IMHO!!..........
--
Kelly Troyer
"Dyke Delta"_13B ROTARY Engine
"RWS"_RD1C/EC2/EM2
"Mistral"_Backplate/Oil Manifold
-------------- Forwarded
Message: --------------
From: "Kelly Troyer" <keltro@att.net>
To: tntholt23@bellsouth.net (Timothy Holt)
Subject: More Charging Circuit Info
Date: Sun, 30 Aug 2009 20:06:30 +0000
For your informaton here is additional justification in my
opinion for going to an external
regulator in our aircraft and having the ability to either automaticly
or manualy cut power
to the field windings in case of a shorted regulator............Note
that solid state regulators
tend to fail "Shorted" about 50% of the time and all current
internal regulators are solid
state.............Link Below..................."Nuff Said"
!!...............IMHO