Mauledriver(at)nc.rr.com
Guest
|
 Posted: Sat Jun 29, 2019 4:44 am Post subject: The joys of a Z-14 during an charging system failure |
 |
|
An update on this old post - the LR3C did not fail as I concluded
originally - the failure was due to a 'bad wire' (18ga Tefzel)
The situation below was initially determined to be an intermittent
failing LR3c regulator. The offending regulator was returned to the
factory and a used unit from my shelf installed which seemed to work...
until more intermittent failures were experienced.
After much probing with a volt meter I determined that the wire from the
main alternator running back to the LR3c pin 4 was fractured internally
(!!). Now, I could not find the point at which it was fractured because
the insulation was intact. But continuity testing did seem to indicate
an unseen break in the wire. While this seemed and seems highly
unlikely, I could reach no other conclusion. The wire did go from the
regulator, thru a firewall penetration, around the engine and then was
split into 2 leads to feed both terminals of the plug on the B&C L-40
alternator. Continuity checks from that split to the regulator end of
the wire showed intermittent continuity.
Obviously the engine vibrates and translates all over the place during
operation, perhaps more than allowed for by my wire routing technique.
I have taken advantage of the dual terminals on the L-40 and run 2
separate wires, along 2 separate routes, back to a single terminal on
the regulator and all seems to be well.
As frustrating as this problem was, and given the extended time period
required to finally diagnose and fix, the Z-14 turned out to be very
tolerant of not only the intermittent failure, but of the extended fix
time. I was able to continue to fly without too much concern.
Thanks Bob!
On 4/15/2019 10:39 AM, Bill Watson wrote:
| Quote: |
<Mauledriver(at)nc.rr.com>
Having just passed 1100 hours on my RV-10, I experienced my 2nd LR3C
voltage regulator failure. Like the first, this turned out to be a
non-event despite some difficulty in problem determination.
I installed a Z-14 dual bus, dual alternator, dual battery electrical
system. Specifically a B&C L-40, a B&C SD-20, (2) Odyssey PC680s, and
(2) LR3c B&C regulators. Dual mags but an electrically hungry panel
with (3) GRT EFISs and the rest of the usual kitchen sink.
The charging system failure occurred during cruise in the normal
configuration; i.e. with both buses running independently and not
linked. I first noticed the voltage slowly drop on bus1. I switched
the cross-link on and off a few times and observed the voltage climb
each time suggesting something on bus1 had failed but bus2 was running
fine.
Soon the low voltage light lit so I simply switched the cross link on
and completed the 2 hour leg.
Upon landing and suspecting an LR3c failure, I ran through the problem
determination procedure per B&C. Problem was it all checked out so I
call them and they said it was probably a failed alternator. I sent
it in, they checked it out, the 1100 hour L-40 was just fine so they
sent it back for the cost of postage. I reinstalled it, reset the
belt tension and took a test flight.
All was well on the test flight so a week later I went on a 3 leg
journey to DC, Pgh and return. No problems on the first 2 legs but on
the third leg, bus 1 was out again. It was a non-event relative to
finishing the 1.5 hour leg.
I re-ran the regulator's PD procedure and step 4 failed (no voltage
drop for those following along). Since I had a previously repaired
one on the shelf, I simply swapped it out and was off and flying again.
Findings:
- The LR3c can 'soft-fail' and can be suspect even if PD checks out.
- The 20amp backup alternator is capable of running my full daytime
cruising load including battery charging. It only comes up short at
low RPMs during ground ops.
- The 40amp main alternator is enough for my fully loaded RV10 and
will keep things running and charging even during low RPM ground ops
(I already knew this).
- The Z-14 provides a great deal of 'dispatch reliability'. I can
finish out a trip and get home safely in most instances even with a
failed regulator or alternator. I feel confident enough to take off
with one side failed if need be, an example being on trips to the
Bahamas as long as battery life will carry me to an airport even with
a 2nd charging system failure.
- Don't mount the LR3c on the back of the firewall up under the RV10
panel where it is so *^*&^I%%$$#GD hard to get at for adjustment or
replacement.
Bill "experiencing the joys of ongoing OBAM aircraft maintenance" Watson
---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
|
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
