From: Rotary motors in
aircraft [mailto:flyrotary@lancaironline.net] On
Behalf Of Ed Anderson
Sent: Friday, May 15, 2009 4:33 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: EXP 2V
Bus
Welcome, Bryan
As I indicated the EXP2 may not be a bad
choice, the only downside I could see is making later additions. Let me
forewarn you - as an alternative engine experimenter, there is a strong
likelihood that you will make changes {:>)
Ed
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Bryan Winberry
Sent: Friday, May 15, 2009 4:20 PM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: EXP 2V
Bus
Thanks Ed,
I actually stumbled on your account on the
aeroelectric website.
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Ed Anderson
Sent: Friday, May 15, 2009 3:31 PM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: EXP 2V
Bus
Hi Bryan,
While I do not fly with the EXP2V bus, I
do have some knowledge of it as I helped an RV-6A owner with an electrical
problem who had one.
It turns out the EXP2V electrical
problem was not due to the EXP2V solely – it had considerable help from
someone who had screwed up and fried the on-board relay and then
attempted to Jump the relay position rather than replacing the on-board
relay. The results were that without the relay and with the non-factory
jumper (there is a factory jumper apparently with a diode embedded in it which
can be used to replace the relay – but a piece of wire won’t work)
– the battery stayed connected to the board load and more importantly to
the alternator continuously. That was fine in that it kept the battery
connected and charged while the engine was running, however, upon engine shut
down, This connection would drain the battery overnight and next day - no power
to start the aircraft. With the relay in place when the master switch is
turned off the relay opens removing the battery from the alternator circuit,
but that could not happen with this self made jumper in place.
Upon examination it was apparent that very
high currents had been applied to some of the traces on the board, the copper
traces had gotten hot enough to cause the solder coating to flow –
undoubtedly this current also was responsible for frying the relay.
Initially, I was not highly impressed with
the EXP2V but the more I examined the circuit the more I became convinced
that particularly for those “electrically challenged” this might
not be a bad way to go. The only downside I have heard is that trying to
wire in later electrical additions to the board can be frustrating as you only
have so many switches and circuits on the board. The polyfuses
(automatically reset) have gotten a lot of attention (not all favorable) but I
do not personally know of anyone who has had any bad experiences with
them. I wired my own panel and therefore know it intimately, so changes
are no problem. However, as I indicated, this might be a better choice
than trying to wire your own if you do not feel knowledgeable or comfortable
about doing so.
I did come to one conclusion about the
high current flow. In looking at the circuit diagram, it became clear
that if someone had been messing with the alternator AND had left the EXP2V
master switch ON and then permitted the “B” lead of the alternator
to become grounded – even temporarily – that would ground the
battery through the board and the on-board relay. I strongly suspect that
this is what happened and with the resulting high current flow which fried the
relay and melted the solder – so one could surmise that the board
withstood the abuse about as well as any circuit could have.
I have no vested interest one way or the
other, just passing on my observations and opinion.
Ed
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Bryan Winberry
Sent: Friday, May 15, 2009 1:27 PM
To: Rotary
motors in aircraft
Subject: [FlyRotary] EXP 2V Bus
Anyone out there using this bus? Would welcome pros
and cons with regard to the Renesis going into a RV-7.
Bryan
Just starting to think about electrical
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