Paul:
I recently finished wiring and electrical checkout on my 914 monowheel.
I'll answer your questions on how I did it according to Bob's bible.
1. I used a switch to take the alternator off line. As I read somewhere it
was bad practice to use a CB as a switch. I have this switch marked as
"primary buss", this is alongside the switch marked essential bus alternate
feed which allows the battery to supply the essential bus when thrown. I
wired the big diode a little different than what is shown in Bob's
schematic. I found that there is about an 0.8 volt drop across the diode.
With this slightly lower voltage my electric horizon gyro doesn't fully
spool up. So I wired the alternate feed switch to bypass the diode when it
is off. When flipped on the battery supplies the essential bus but the
diode keeps it from driving the main bus. If you look at figure Z-16 I just
put a wire from the top of the main bus to the open terminal 3 of the E-bus
alternate feed switch shown on that schematic. That way the electric gyro
always gets full voltage.
2. I used the tapped hole on top of the engine case just to the right of
center. I used #4 gauge welding cable for both the ground and power
lines, with crimped ring connectors on each end.
3. I used the fusable links as shown on the Aero Electric schematics
instead of the slo blo fuses.
4. The #6 ring connector is a number 6 machine screw 6-32 not 6mm.
5. I would think if you were trimmed for straight an level flight and your
engine fell off you would have lost your alternator and primary buss. I
guess having the trim motor on the battery allows you to compensate for the
W&B change for the missing engine.
6. I am using the fuses also but had put another CB between the main and
essential busses as shown in the schematic that comes with the diode used
to isolate them.
7. The Westach 712-4D6K K type thermocouple is used.
8. My GPS antenna in inside the fuselage above my head in the space beteen
the doors. It is attached to the trim panel I put above to mount interior
lights etc.
Steve Hagar
A143
Mesa, AZ
> [Original Message]
> From: Paul Stewart <europa@pstewart.f2s.com>
> To: europa-list@matronics.com <europa-list@matronics.com>
> Date: 1/1/04 6:23:16 AM
> Subject: Europa-List: electrics
>
>
> Having now read 'lecrtic Bob's book twice I fear there is no excuse to
> put off delving into electrics any longer. However I have a few
> questions I have not as yet found answers to so if anyone can shed light
> onto one or more of them I would be very grateful.
>
> 1. If (as I intend to) I use OV protection via a relay and 5A c/b,
> can I do away with an alternator/generator output switch and pull the
> c/b when I want to deliberately take the alternator off line (don't know
> when that would be)?
>
> 2. Where exactly have folk attached engine block grounding straps?
> There are many tapped holes in the engine block without apparent use -
> can I use any suitably placed one?
>
> 3. What do folk use and where does one get the 30A slow blow fuse
> required for battery feed and alternator/generator feed to the main bus?
>
> 4. On 'lectric Bob's web site he sells AMP PIDG crimp connectors. Does
> any one know if what he refers to as #6 ring terminal is M6 ? ( the
> combination of metric everything on the engine and imperial everywhere
> else is becoming a bit of a pain)
>
> 5. I don't quite follow why, if there is a requirement for the trim
> motor to be wired directly off the battery rather than the bus bar, the
> same is not true of at least one of the 914 fuel pumps - surely these
> are as much if not more flight critical than the trim motor?
>
> 6. I intend to wire using fuses rather than c/b ( OV protection
> excepted) - is there anything other than this which 'must' be protected
> by c/b rather than fuse?
>
> 7. What EGT probes have folk used for thier Rotax installations?
>
> 8. Am I correct in thinking GPS antennas con 'see' through fibreglass?
> (I know this has been discussed before)
>
> Thanks in anticipation and a Happy New Year to all..Regards
>
>
> Paul Stewart #432
>
>
>
>
>
--- Steve Hagar
--- hagargs@earthlink.net
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