Date: Thu, 21 Nov 2013 10:35:14 -0600
Reply-To: JRodgers <jrodgers113@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: JRodgers <jrodgers113@GMAIL.COM>
Subject: Re: High beams not working-lighting upgrades!
In-Reply-To: <BAY403-EAS264FA92C91C57E28F27215DA0E10@phx.gbl>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Dennis,
It would seem that to improve the electrical delivery the first place to
start would be to clean up all the grounds, then increase wire sizes to
reduce the load resistance. Ya want to increase in water flow - increase
the size of the pipe, so to speak - but be sure the tap (ground) at the
end is also adequate to the task.
A little aside - on the vanagons - and all other vehicles so far as I
know - pretty near all power goes through the ignition switch. If the
switch fails - the ignition is lost, everything is lost, can't start the
car/van. On airplanes - the electrical system is on a Master Switch -
and all ignition is on magnetos tied to a magneto switch. Turn on the
magneto switch - nothing happens, but the engine is ready to go. Then
turn on the master to energize the electrical system - hit the starter
button - and the starter engages turning the engine and the magnetos
kick in and activate the spark plugs - engine goes. Release the starter,
engine keeps running, alternator is now charging and you are ready to
go. You can actually turn off that master switch and the engine will
keep running. Typically in a car to shut the engine off you simply turn
the ignition switch off. While you can do that in an airplane - turn the
magneto switches off - it is not done in practice for safety reasons.
The procedure is to pull or shut off the mixture control with starves
the engine of fuel until it quits - then turn the ignition/magneto
switches off. Note I say "switches" because airplane typically have two
magnetos - for both safety and efficiency. But those puppies will not
turn off unless they are grounded or the engine is starved of fuel. Air
Craft magnetos have a spring loaded spark retarding device the retards
the spark for start up, but when it trips - it give a terrific charge to
the sparking plugs. If there is any residual fuel in the system - and
someone is working around the propeller - that trigger could kick the
engine over and hurt someone.
The split system is nice in that even if the battery is dead and the
electrical system cannot be activated - if the magnetos and the ful are
turned on - one can had start the engine by pulling the propeller
through it's arch briskly by hand. When the mag retarder kicks - the
engine will start.
I have owned a couple of Cessna 195's in my day. They had 7-cylinder
"Shakey Jake" engines - Jacobs engines - which used a single magneto on
one side and an automotive type distributor on the other. I can tell you
- distributors make life a whole bunch easier.
But it was always a little weird to have a distributor all torn apart on
the work bench rather than a magneto!!
Question? - Are there automotive magneto applications currently in use
in the Auto Industry.?
John
On 11/21/2013 9:15 AM, Dennis Haynes wrote:
>>From the factory the 90 amp alternator was already an upgrade to support AC
> and the larger radiator fans that went with it. It is plenty sufficient
> until crazy loads are added. As for over current protection there are things
> to consider including avoiding nuisance disconnects, especially lighting,
> ignition, and fuel delivery. The Europeans use a separate fuse for head
> filament and the rear is split left-right. The Americans use a
> self-resetting breaker for the headlights so you get the lights flashing in
> case of an overload. Fuse links are also an option for the larger wires.
>
> How much re-engineering do we want to do? What is there has worked for 22+
> years.
>
> A consideration for increasing the alternator capacity is "driving" it. The
> single belt can only transmit so much power and with the limited wrap around
> the drive pulley makes things worse. Even 120 amp alternators make for very
> short belt life. BTDT.
>
> Dennis
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> Bret Berger
> Sent: Thursday, November 21, 2013 1:43 AM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: High beams not working-lighting upgrades!
>
> Sounds like a good reason to install a properly sized fuse inline with a
> wire gauge upgrade. Perhaps an alternator upgrade would also be in order?
> Any voltage drop across your headlight/radiator fan/blower motor supply wire
> implies waste heat being dumped from the wire. Power = current x voltage.
> A 2 volt drop in a supply wire with a 20 amp load is
> 40 Watts wasted.
>
> On 11/17/2013 6:35 PM, Dennis Haynes wrote:
>> Most auto equipment will work over a large voltage range but
>> performance does suffer. However it is not by accident or even cost
>> savings that the wiring is "undersized". As the system gets loaded
>> down thee resistances help to control the load on the alternator.
>> Also, as so much wiring is not over current protected the smaller
>> sizes also help to limit or control fault currents. Yes those wires
>> can act as fuses hopefully burning up enough to open before the van is
> gone.
>
