Today's Message Index:
----------------------
1. 12:21 AM - Battery Dump (Bob Lee)
2. 06:22 AM - Re: LOAD DUMP (Paul Messinger)
3. 08:35 AM - BNC Connector (Gerry Clabots)
4. 09:32 AM - Re: BNC Connector (Richard E. Tasker)
5. 12:23 PM - RF breakthrough on Vans gauges (Richard Garforth)
6. 12:41 PM - Re: Re: LOAD DUMP (Wallace Enga)
7. 05:00 PM - Smoke in wires. (Rob W M Shipley)
8. 05:00 PM - Re: BNC Connector (Robert L. Nuckolls, III)
9. 05:03 PM - Re: Re: LOAD DUMP (Robert L. Nuckolls, III)
10. 05:28 PM - RF interference to Vans gauges (Robert L. Nuckolls, III)
11. 06:56 PM - Re: BNC Connector (HCRV6@aol.com)
Message 1
| INDEX | Back to Main INDEX |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
--> AeroElectric-List message posted by: "Bob Lee" <bob@flyboybob.com>
Bob,
I just checked the FAQ on Aeroelectric.com and did not find any update on
the Battery dumping subject that went around a while back. Did I miss your
reply or has the testing not been completed? I understood that you had
several ideas that you were planning to test that would provide an
inexpensive solution to this risk but then the subject went quiet.
Regards,
Bob Lee
mailto:bob@flyboybob.com
Message 2
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
--> AeroElectric-List message posted by: "Paul Messinger" <paulm@olypen.com>
Testing has been delayed and I have posted several updates on this; the
latest not long ago.
Other more important (to me) Tasks have kept me off this project. Plus I am
still waiting for calibration on one piece of test equipment (being done
free in spare time so its taking much longer to do, however its a 40-80 man
hour cal so its not trivial to get done free).
Yes we have a couple of solutions that appear on paper to completely solve
any Load dump issues. However to prove to Bob (and others) the solution
works, requires a high power setup with somewhat unusual instrumentation (at
least for me). I am not setup for switching and loading 50 amps at 20 to 80
volts so that has taken some time to get parts for and setup such power
testing and associated instrumentation and get it calibrated so the results
are meaningful and design margins can be determined.
My aircraft already has one solution implimentated (actually done several
years ago) based on reading extensive industry info on the subject. Thus the
planned testing is not something I need for my own design.
In the automotive design, damaging Load Dump's only can occur when there is
a failure as the battery is hard wired to the alternator "B" lead. There is
a small load dump when you turn off your headlights but the battery absorbs
the dump transient current pulse and keeps the voltage under normal levels.
The issue in aircraft is different where the battery can be disconnected
when the alternator is providing power. This can be either a design where
its a simple switch function (pilot error :-) ) or the battery contactor
failing open. Also if the OVP is used to open the "B" lead with an
internally regulated alternator any opening of the "B" lead during
alternator operation can overvoltage the alternator regulator and if that
regulator/alternator is not designed to survive load dumps it/they will
fail. The current continues for a very short time and the voltages rises
until some load path dissipates the current. The voltage rises as needed to
provide this load path and voltages can rise to very high levels. The way a
IGN coil produces the spark is similar where the primary coil voltage rises
from 12V to 350-400V where it is clamped if the spark plug has not fired and
dumped the load into the spark.
This MAY be the reason for the "reported" failures of the rebuilt ND
alternators being sold by Vans for the RV market. I do not know of ANY proof
of this however, that is "Vans alternators are inferior" to any other source
as has been suggested by some on this list.
Testing is more complex than it might seem however to be sure the solution
has proper design margin.
Consider that the industry has a simple product that is specifically
designed for this issue and one poster said that product failed for him (I
have an equivalent part and will be trying it also, however its clamping
voltage is higher than aircraft avionics can tolerate). Thus the need for
careful testing of a somewhat complex issue of transient energy etc.
Hopefully the testing will not damage the regulators in my test alternators
as I do not have a limitless supply.
Regardless its not possible to test all possible alternators and regulator
combinations so any solution must have a somewhat large design margin which
is hard to determine when the alternator/regulator(s) I have to test are not
necessarily worst case etc. For example I do not have any ND alternators nor
any of Bob's regulators to test. The peak current capability of the
alternator as well as the response time of the regulator are major factors.
I have never called it anything but Load dump as that has been the industry
term for decades. Bob, as I recall, did want to rename it (do not recall
that name) so looking for anything but Load dump will not flag any note from
me.
Regardless the testing will not be exhaustive and no warrenty it will result
in a 100% solution for everyone. The best design solution is one where its
not possible to switch into a load dump condition with pilot errors.
Thus our solution is not to try to protect the alternator/regulator but the
avionics etc on the acft by clamping the spike to levels the avionics can
survive. The OVP circuit will NOT protect from load dump as shutting off the
regulator is too late. Opening the "B" lead contactor is not a solution
either as the contactor takes a long time to open compared to the load dump
pulse.
Paul
----- Original Message -----
From: "Bob Lee" <bob@flyboybob.com>
Subject: AeroElectric-List: Battery Dump
> --> AeroElectric-List message posted by: "Bob Lee" <bob@flyboybob.com>
>
> Bob,
>
> I just checked the FAQ on Aeroelectric.com and did not find any update on
> the Battery dumping subject that went around a while back. Did I miss
your
> reply or has the testing not been completed? I understood that you had
> several ideas that you were planning to test that would provide an
> inexpensive solution to this risk but then the subject went quiet.
>
> Regards,
>
> Bob Lee
> mailto:bob@flyboybob.com
>
>
Message 3
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
--> AeroElectric-List message posted by: "Gerry Clabots" <gclabots@execpc.com>
Does someone have a part number and a source for a 90 degree BNC connector that
I could use where I connect the coax to the antenna.I will be mounting the antenna
under the baggage compartment floor.
Thanks
Gerry 7A 70188
Message 4
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: BNC Connector |
--> AeroElectric-List message posted by: "Richard E. Tasker" <retasker@optonline.net>
I don't have a part number, but unless you just do not have the room,
you would be better off (financially and signal strength) to use a
regular straight connector and bend the cable.
Dick Tasker
Gerry Clabots wrote:
>--> AeroElectric-List message posted by: "Gerry Clabots" <gclabots@execpc.com>
>
>Does someone have a part number and a source for a 90 degree BNC connector that
I could use where I connect the coax to the antenna.I will be mounting the antenna
under the baggage compartment floor.
>Thanks
>Gerry 7A 70188
>
>
Message 5
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | RF breakthrough on Vans gauges |
--> AeroElectric-List message posted by: "Richard Garforth" <richard@hawk.flyer.co.uk>
Brian & Jim,
Thanks for the suggestions.
Taking the easiest first both antennas are already cabled in RG400 - thanks Jim.
I explored the situation further today and found that a handheld ICOM xmitter produced
the same result - this confirmed it is RF breaking into the gauge or the
wiring and not some strange earthing issue. I next removed the gauge and MAP
sensor and cable from the aircraft and set up a simple bench test. This showed
that the RF is getting into the circuit board in the gauge (even through the
glass front). I stripped the gauge down and found there is no HF decoupling
to be seen. Also it seems the moving coil meter is centre wound ( 3 terminals)
and works on a differential output from the driver chip. The MAP sensor appears
to be a 4 arm bridge sensor with a built in regulator. I finished up fitting
five 10nF disc caps (thanks Brian) on the meter circuit board.
One across each meter coil, one across the two signal arms of the bridge input
and one from each signal input to ground. Immediately the interference was reduced
considerably. Final fix was to take the MAP sensor out of its plastic box
and fit it directly to the rear of the meter and fit ferrite beads to the two
signal leads and the power input.
The end result is a gauge that only moves a needle width with the ICOM xmitter
ant held against the meter front.
My guess is that the Vans gauge that gives similar problems, the ammeter, being
centre zero has a similar internal configuration and may respond to a similar
fix. As I am a committed Voltmeter believer I can only speculate.
Richard(G-RVIX)
Message 6
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
--> AeroElectric-List message posted by: Wallace Enga <wenga@svtv.com>
Paul
I appreciate the efforts you are doing to investigate and resolve this Load
Dump anomaly.
I have more than a passing interest, as I am using this combination of an
Alternator with
Internal V.R. and Bob's O.V. Module.
When the O.V Disconnect ("B" lead) Contactor opens, I can understand the
transient current pulse caused
by the now open circuit on the Alternator side, but I fail to see, how
this could cause an O.V. spike on the
bus side, which is now isolated from the Alternator in the Load Dump scenario.
Why doesn't the bus voltage just drop to the Main Batt level or in the case
of the pilot mistakenly
opening the BATT Contactor, drop to zero?
Isn't the very condition which causes the transient current pulse, (the
Open "B" lead Contactor) ,
the result of the busses/batt no longer being connected to the Alternator?
What am I missing here?
Wally Enga
RV7
Message 7
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
--> AeroElectric-List message posted by: "Rob W M Shipley" <rob@robsglass.com>
I received this in my mail the other day and felt that it might contribute much
to the erudite discussions we enjoy so much in this list. As an English ex-pat
I am intimately aware of the excellence of Lucas products and their contribution
to reliability of the fine automobiles made in the British Isles.
> << "A Treatise on the Importance of Smoke" by Joseph Lucas
> All electrical components and wiring harnesses depend on proper
> circuit functioning, which is the transmission of charged ions by
> retention of the visible spectral manifestation known as "smoke".
> Smoke is the thing that makes electrical circuits work. Don't be
> fooled by scientists and engineers talking about excited electrons
> and the like. Smoke is the key to all things electrical.
>
> We know this to be true because every time one lets the smoke out of
> an electrical circuit, it stops working. This can be verified
> repeatedly through empirical testing. For example, if one places a
> large copper bar across the terminals of a battery, prodigious
> quantities of smoke are liberated and the battery shortly ceases to
> function. In addition, if one observes smoke escaping from an
> electrical component such as a Lucas voltage regulator, it will also
> be observed that the component no longer functions.
>
> The logic is elementary and inescapable! The function of the wiring
> harness is to conduct the smoke from one device to another. When the
> wiring harness springs a leak and lets all the smoke out of the
> system, nothing works right afterward.
>
> Starter motors were considered unsuitable for British motorcycles for
> some time largely because they regularly released large quantities of
> smoke from the electrical system.
>
> It has been reported that Lucas electrical components are possibly
> more prone to electrical leakage than their Bosch, Japanese or
> American counterparts. Experts point out that this is because Lucas
> is British, and all things British leak. British engines leak oil,
> British shock absorbers, hydraulic forks, and disk brake systems leak
> fluid, British tires leak air and British Intelligence leaks national
> defense secrets.
>
> Therefore, it follows that British electrical systems must leak
> smoke. Once again, the logic is clear and inescapable.
>
> Sometimes you may miss the component releasing the smoke that makes
> your electrical system function correctly, but if you sniff around
> you can often find the faulty component by the undeniable and
> telltale smoke smell. Sometimes this is a better indicator than
> standard electrical tests performed with a volt-ohm meter.
>
> In conclusion, the basic concept of transmission of electrical energy
> in the form of smoke provides a clear and logical explanation of the
> mysteries of electrical components and why they fail.
>
> "A gentleman does not motor about after dark."
> - Joeseph Lucas, 1842 - 1903
I learned a long time ago that once you let the "Factory Smoke" out of any electrical
device, it is next to impossible to replenish it.
Message 8
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: BNC Connector |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 12:26 PM 5/9/2004 -0400, you wrote:
>--> AeroElectric-List message posted by: "Richard E. Tasker"
><retasker@optonline.net>
>
>I don't have a part number, but unless you just do not have the room,
>you would be better off (financially and signal strength) to use a
>regular straight connector and bend the cable.
>
>Dick Tasker
>
>Gerry Clabots wrote:
>
> >--> AeroElectric-List message posted by: "Gerry Clabots"
> <gclabots@execpc.com>
> >
> >Does someone have a part number and a source for a 90 degree BNC
> connector that I could use where I connect the coax to the antenna.I will
> be mounting the antenna under the baggage compartment floor.
> >Thanks
> >Gerry 7A 70188
Right angle connectors do exist . . . but are comparatively
expensive and not in everybody's catalog. Here's a new article
on a low cost but rugged alternative to a one-piece, solderless
right-angle connector.
http://www.aeroelectric.com/articles/BNC_Rt_Angle/BNC_Rt_Angle.html
Bob . . .
-----------------------------------------
( Experience and common sense cannot be )
( replaced with policy and procedures. )
( R. L. Nuckolls III )
-----------------------------------------
Message 9
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 02:41 PM 5/9/2004 -0500, you wrote:
>--> AeroElectric-List message posted by: Wallace Enga <wenga@svtv.com>
>
>Paul
>
>I appreciate the efforts you are doing to investigate and resolve this Load
>Dump anomaly.
>
>I have more than a passing interest, as I am using this combination of an
>Alternator with
>Internal V.R. and Bob's O.V. Module.
>
>When the O.V Disconnect ("B" lead) Contactor opens, I can understand the
>transient current pulse caused
> by the now open circuit on the Alternator side, but I fail to see, how
>this could cause an O.V. spike on the
>bus side, which is now isolated from the Alternator in the Load Dump scenario.
It doesn't. The issue came to light when a number of folks
having alternators wired per figure Z-24 cycled them OFF and ON
when the engine was running and the alternator was probably carrying
moderate to high loads. The resulting load dump transient was
confined to the alternator side of the alternator disconnect contactor
and only the alternator's internal voltage regulator was damaged.
>Why doesn't the bus voltage just drop to the Main Batt level or in the case
>of the pilot mistakenly
>opening the BATT Contactor, drop to zero?
>
>Isn't the very condition which causes the transient current pulse, (the
>Open "B" lead Contactor) ,
>the result of the busses/batt no longer being connected to the Alternator?
>
>What am I missing here?
Not a thing.
Bob . . .
-----------------------------------------
( Experience and common sense cannot be )
( replaced with policy and procedures. )
( R. L. Nuckolls III )
-----------------------------------------
Message 10
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | RF interference to Vans gauges |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 04:13 PM 5/7/2004 -0500, you wrote:
>--> AeroElectric-List message posted by: "Alex Peterson"
><alexpeterson@earthlink.net>
>
>
> >
> > Seen some old postings regarding this issue - Has anyone
> > found a fix yet? My MAP gauge goes full scale using a top
> > antenna but only part full scale using an underside antenna.
> >
> > Richard G-RVIX(RV9A)
>
>Richard, the fix is to not look at it while transmitting:>)
That's one alternative. This is a down-side of some
hardware supplied to the OBAM aircraft community. Some
products are brought to the marketplace by folks who
either don't understand the value of making products
perform equal to or better than "certified" stuff -OR-
they don't understand the environment in which they
are working.
There is no excuse for not having fixed this
problem by now. I've been hearing about it off-and-on
for at least a year. As consumers you have several
choices: (1) return the hardware for refund as
"not suited to the intended task", (2) work out
and implement fixes at your own time and expense,
(3) work with the original manufacturer to see if
he/she is willing to upgrade your purchase to operate
in the real world or (4) just live with it. It
doesn't hurt anything as long as you understand
the condition and can believe the instrument all
times other than transmitting.
As always, if anyone does put the wrenches to the
manufacturer, tell them I'll offer suggestions for
modifying their design . . . perhaps even at no
cost. But since I don't own any of this stuff,
it's up to those to do own it to be responsible
consumers and squeeze these folks into useful
action.
There's an old adage that suggests "If
you continue to do as you've always done,
you will continue to be as you've always been."
A corollary to this adage says, "Until you convince
a supplier that their product has unsatisfactory
design flaws and insist on responsible adjustments,
they'll continue selling it warts and all to your
fellow builders . . . and your's won't get fixed either.
Bob . . .
-----------------------------------------
( Experience and common sense cannot be )
( replaced with policy and procedures. )
( R. L. Nuckolls III )
-----------------------------------------
Message 11
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: BNC Connector |
--> AeroElectric-List message posted by: HCRV6@aol.com
In a message dated 5/9/04 8:36:50 AM Pacific Daylight Time,
gclabots@execpc.com writes:
<< Does someone have a part number and a source for a 90 degree BNC connector
that I could use where I connect the coax to the antenna. I will be mounting
the antenna under the baggage compartment floor. >>
I used a 90 degree BNC adapter from Radio Shack for the same installation,
hope it works.
Harry Crosby
Pleasanton, California
RV-6, final assembly
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|