REFLECTOR: Electrical Diagram

Patrick Sieders pjsieders at comcast.net
Thu Jan 9 10:42:16 CST 2014


All,

 

Here is an updated electrical diagram as per request. I added a diode to
feed the emergency bus at all times with two sources available to it. Also
installed the Battery master switches.

 

Comments ?

 

Patrick

 

 

Patrick & Dana Sieders

7244 Sugarloaf Drive

Nashville TN 37211

 

Tel. 615-250-2304

Cell P. 615-918-2698

Cell D. 615-918-2699

 

Email. Js3201 at comcast.net

Http://www.sieders.com/sieders

 

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Patrick Sieders
Sent: Monday, December 30, 2013 7:44 AM
To: 'Velocity Aircraft Owners and Builders list'
Subject: Re: REFLECTOR: Electrical Diagram

 

Glenn,

 

Yes both batteries will be connected to the system with master relays. They
will be both powered off their resp. battery.

 

So, When in normal ops : The main batt and Primary Alt power the main bus
bar and consequently the VP-X. The B/U Batt and the B/U Alt power the non
essential items. Those are seatheaters and trickle charging of battery
backups in diverse instruments. We have to separate systems, due to the
transfer relay being unpowered, i.e. the (manual) switch is in Norm
position, which is "Primary + Backup (separate circuits)

 

When the main Alternator quits, the main busbar and thus the VP-X sense a
low voltage and a visual alert will be displayed on the screen. If a restart
of the Primary Alt is not possible, I can switch to "Backup Alt on Main
Bus", which connects the batteries in parallel (or I can disconnect the
batteries individually through their batt switches), the transfer relay is
powered and switches, the Field power for the Primary Alt is removed, the
Backup Alt is connected to the main bus bar, and the field power is
connected to the VP-X. Also due to the transfer relay switching, the non
essential bus is now unpowered and the emergency bus is powered. The
emergency bus connects only to three instruments at this time, connected to
their second power input. The VP-X does not remove power from the transfer
relay, remember t's a manual switch. The only way power is removed is when I
do it, or the main bus voltage slips below the level which is needed to
trigger the relay.

 

Another option is to switch to Backup Alternator system only. This will give
me power only to the emergency bus, with which my 3 emergency instruments
are powered and can get me to the ground. The transfer relay is not powered,
and the main system can be shutdown. This is in case of a total electrical
failure in the main system. At that point the transfer relay cannot be
powered, since its received its power from the main system. Within the VP-X
I can also disconnect the field to the B/U Alt in case of a fault. Two sense
lines will be connected from the batteries to the VP-X so I will have
Voltage levels available at all times, except when the VP-X is shutdown.

 

Now, to give some more info : The backup battery  and B/U Alt will never
supply more than 40 Amps. The fuse between the B/u alt master relay and the
transfer relay protects the relay at 40 amps. The B/U Alt is a plane power,
with built in Volt Regulator (VR) 30Amps. Thus loadshedding will have to be
performed before switching the B/U Alt to the main system. And starting is
only done from the main system. 

 

One thing I agree on is that the emergency bus in this drawing is only
powered by switching a relay. I am thinking of putting in a Zener Diode and
connect it to the main line (left of the emer. Bus). This will provide power
to the emergency bus at all times.

 

I know it's a lot to take in. Hope it all makes sense.

 

Gr. Patrick

 

 

 

 

Patrick & Dana Sieders

7244 Sugarloaf Drive

Nashville TN 37211

 

Tel. 615-250-2304

Cell P. 615-918-2698

Cell D. 615-918-2699

 

Email. Js3201 at comcast.net

Http://www.sieders.com/sieders

 

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Glenn Falkenberg
Sent: Sunday, December 29, 2013 11:09 PM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: Electrical Diagram

 

Hi Patrick

I have the same question as Brian.  When the secondary alternator transfers
over to power to the main bus, it looks like the transfer relay supplies
power to the emergency bus from the backup battery.  Are your batteries
connected to the system via relays or switches?  From your schematic it
looks like relays. Another question, does the VP-X remove power from the
transfer relay in the event of the second alternator fault?  If it does
remove power, the relay will relax and you wont have power available from
the backup battery. This would also remove power from the emergency bus.  I
really like the concept of running essential and non-essential buses off two
alternators. 

 

On Sun, Dec 29, 2013 at 3:16 PM, Patrick Sieders <pjsieders at comcast.net>
wrote:

Hello All,

 

I have been working on my electrical diagram for a while now and I am about
to put it in the airplane. But, it's always nice to have a second look (or a
third, fourth...) , especially someone with experience with the VP-X system.
And so I present to you my simplified main power system. Now I know that
this might spark a discussion about how simple your electrical system should
be, I understand, but that is not what I asked for help.

 

A little explanation : I wanted to use both my alternators at the same time,
on separate busses. The VP-X as you might know, only accepts one at a time.
So I made a circuit that makes it possible for my backup alternator to
disconnect from the non essential bus (seat heat etc.) and connect to the
main bus in the event my main alternator quits. If the backup alternator
quits as well, then the main battery will be used for emergency power, which
depletes. The backup battery will feed emergency instruments via power input
#2 on those particular instruments, when the power of the main batt drops
below it's own level.

 

My question is for you to find any scenario and/or electrical situation that
can occur which would be detrimental to the system. Ask me questions if you
have them.

 

Thanks for your participation, and if I do not speak to you until the new
year, Many blue skies and soft landings for 2014 !

 

Patrick

 

 

Patrick & Dana Sieders

7244 Sugarloaf Drive

Nashville TN 37211

 

Tel. 615-250-2304

Cell P. 615-918-2698

Cell D. 615-918-2699

 

Email. Js3201 at comcast.net

Http://www.sieders.com/sieders


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