Today's Message Index:
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1. 08:33 AM - Re: Voltage question and start (Bitterlich, Mark G CIV NAVAIR, WD)
2. 09:48 AM - Re: Voltage question and start (greg.barnhard@gmail.com)
Message 1
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| Subject: | Voltage question and start |
Your grasp of the theory involved is totally accurate. There is not a large current
draw on the batteries when starting an M-14 with the compressed air starting
system. Of course that totally assumes that your batteries are in good shape.
Simply check your battery voltage to be sure. Thus, the only thing that
happens when the generator is connected to the main electrical bus is that
voltage goes from about 24, to (typically) 28 VDC. On the other hand in an aircraft
with an electrical starter, the instant current draw from the starter is
huge, and it can easily pull the battery voltage down very low, and there can
be a pretty decent spike as a result.
Another very obvious thing to keep in mind is that with our standard generator,
the generator is disconnected and then reconnected every time you bring the engine
to idle. I doubt you are going to turn off all the Avionics just because
you pull the throttle back! :-)
Typically something like your "GAD 27" is nothing more than a big capacitor which
tends to smooth out any voltage changes and a diode to prevent the cap from
back-feeding the whole aircraft electrical bus. You could easily build your
own if you really wanted to.
So again, with strong emphasis on having good batteries, the Yak-52 with not have
the same voltage spike potential that say a Cessna 180 might have.
Mark
-----Original Message-----
From: owner-yak-list-server@matronics.com [mailto:owner-yak-list-server@matronics.com] On Behalf Of greg.barnhard@gmail.com
Sent: Saturday, May 20, 2017 3:15 PM
Subject: [Non-DoD Source] Yak-List: Voltage question and start
--> <greg.barnhard@gmail.com>
Good afternoon everyone,
You'll have to forgive my lack of knowledge when it comes to electricity. It has
always been a weak subject of mine.
I'm installing a Garmin G3X touch with a few of the other gizmos associated with
it in my Yak-52W.
When the master comes on, the PFD will power on along with the engine monitoring
information. Garmin offers a GAD 27 which allows for voltage stabilization for
start. My question is, I shouldn't need that for my setup since the electrical
power is used to open the start valve and power the shower of sparks, right?
Those two items shouldn't cause voltage spikes, correct? I believe the GAD
27 voltage stabilization is for those who use conventional electrical starters
with high draw, etc.
Can someone please set me straight?
Thanks!
Greg
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=469464#469464
Message 2
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| Subject: | Re: Voltage question and start |
Thanks everyone for the replies. I managed to do some more research as well. Mark,
thanks for confirming what I thought I knew. That GAD27 is a 14V box and doesn't
apply to my setup. Thankfully I'm lucky to have an alternator on mine rather
than a generator and the voltage draw down will not cause any issues with
the avionics (according to Garmin). They said it would have to draw down below
11V for anything negative to happen and most of their concerns would be with
a 14V system with a transitional electric starter.
Thanks again!
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=469519#469519
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