Today's Message Index:
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0. 04:15 AM - Just A Few Days Left... (Matt Dralle)
1. 01:41 PM - Re: Rotax 912 UL Rectifier wiring (Hugh McKay)
2. 06:14 PM - Re: 912 Bed-Mount bolt torque (Richard Girard)
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| Subject: | Just A Few Days Left... |
Dear Listers,
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Message 1
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| Subject: | Rotax 912 UL Rectifier wiring |
Dave,
Thank you for the additional electrical information and instruction. Refer
ring to the proposed sketch I sent to you, I am proposing a revision; to ch
ange out the existing 5 Amp Breaker/switch 13 to a similar 30 Amp Breaker/s
witch and reconnect the wiring as follows: connect the new 30 Amp breaker/
switch between the existing 30 Amp fuse and the rectifier. All the connecti
ng wire from the shunt/30 Amp fuse/ 30 Amp breaker 13, to the common connec
tion point of the four rectifier wires R, B+, C, and the + capacitor wire i
s stranded # 10 AWG THHN.
I have made a list of all my electrical devices that would be operating dur
ing taxi, take-off, cruise, and landing and calculated the electrical load
for each case in amps. The largest load demand is during take-off and landi
ng. The load demand during cruise is somewhat less. I notice in Phil Lockwo
od=99s article he states that one should expect the Rotax Rectifier/r
egulator to have a maximum output of approximately 18 Amps DC. My total ins
talled electrical load is about 27 amps DC. This means that if during fligh
t all of this installed electrical load was connected, the rectifier could
not meet the demand and the battery would be making up the difference, thus
draining the battery. But this is not the case during cruise, but is the c
ase during take-off and landing. My calculated take-off and landing load de
mand is about 21 Amps DC, while the cruise electrical load demand is around
11.5 Amps DC. If my thought logic is correct this means that during the sh
ort periods of take-offs and landings my battery would not be charging (red
light on), but during cruise it should be charging (red light off). Correc
t?? By still using a Potter & Brumfield W23 series W23-X1A1G-30 push/pull b
utton breaker at this point in the wiring I believe it not only protects th
e wire but still allows me to isolate the battery from the rectifier when t
he engine is no running.
Sorry to be asking you to look at this again. Comments, advice???
Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay@bellsouth.net
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10
From: Dave Alberti
Sent: Wednesday, November 21, 2018 10:42 PM
Subject: Re: RotaxEngines-List: Rotax 912 UL Rectifier wiring
Hugh, the primary function of breakers and fuses is to protect the wire.
=C2-The size of the wire is sized to the expected load and voltage drop d
ue to wire length. Placing a 5 amp breaker ahead of a 30 amp fuse is just a
wasted fuse installation. The fuse will never see a load greater than 5 am
ps. =C2-Replacing the 5 amp with a 30 makes the fuse redundant and unnece
ssary. =C2-If the wire downstream is incapable of carrying more than 30 a
mps it becomes the fuse. =C2-I have seen panels that smoked in RV
=99s and cars and if it happens in a plane you want to be able to strip the
load with the fewest switches possible. =C2-Your drawing will work to is
olate the =C2-charging circuit only if the wire size matches the expected
load with the caveat being you have no protection for the wire between the
breaker and the battery.
Dave Alberti
On Nov 21, 2018, at 8:38 PM, Hugh McKay <hgmckay@bellsouth.net> wrote:
Dave,
I am not an electrical guru so my understanding of electrical terms and fun
ctions in an electrical circuit is very limited. I do need to limit the amo
unt of changes to my panel simply due to space. Therefore, I am attaching a
scanned sketch of what I propose doing, hoping that it will be safe and me
et the electrical requirements for safe operation of the rectifier and give
the isolation requirements described by Rotax. Please refer to the attache
d sketch and the original one line to compare the proposed changes to the o
riginal.
=C2-
You will note on the sketch that I have a common point where I connect 5 wi
res to a common connection (R, B+, C, the wire from the Capacitor, and the
wire from the 30 Amp fuse). Between the 30 Amp fuse and the shunt I propose
using my existing Breaker 13 (Potter & Brumfield Series W23 Push Button Th
ermal circuit breaker W23-X1A1G5 (which is certified to be used as a manual
push to close/pull to open disconnect) rated for 5 Amps having a Trip time
at 200% rating of 6-22 seconds. If necessary I can replace this same ident
ical Potter & Brumfield breaker with Amp ratings up to 50 Amps. By the way
all the breakers shown on the one line are panel mounted Potter & Brumfield
Series W23 Push Button Thermal circuit breakers. I use these breakers rout
inely as disconnect switches to isolate certain sections of the electrical
system on start-up. Do you find any flaws in this sketch?
=C2-
Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
=C2-
Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay@bellsouth.net
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10
=C2-
From: Dave Alberti
Sent: Wednesday, November 21, 2018 1:28 PM
Subject: Re: RotaxEngines-List: Rotax 912 UL Rectifier wiring
=C2-
Hugh, I have an actual contractor (looks like a solenoid) from Spruce desig
ned to use for this application. Mine is on the firewall near my battery.
=C2-My comparison position is prior to your ammeter shunt. You would have
to wire your breaker so that when closed it would energize the solenoid to
close the circuit supplying 12 volts to B+, R and C. =C2-I use a switch
like Cessna, red split battery alternator .
Dave Alberti
On Nov 20, 2018, at 10:31 PM, Hugh McKay <hgmckay@bellsouth.net> wrote:
Dave,
=C2-
Thanks for your clarification of the Rotax instruction concerning disconnec
ting the battery. I went back and read a similar article by Phil Lockwood c
alled =9CTips and Tricks for the Ideal Rotax 912 Installation
=9D published in 2005. In that article he clearly states that the + battery
wire that is connected to R, B+, and C must be disconnected from the batte
ry. Based on my wiring one line drawing where would you recommend I move Br
eaker 13 to isolate the battery, and should I change the breaker to a large
r amp rating?
=C2-
Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
=C2-
Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay@bellsouth.net
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10
=C2-
From: Dave Alberti
Sent: Tuesday, November 20, 2018 9:41 PM
Subject: Re: RotaxEngines-List: Rotax 912 UL Rectifier wiring
=C2-
Hugh, that does not isolate the battery, the rotax drawing drops at relay 1
9 and takes all voltage off the regulator at B+ and R. =C2-<DADA423704E04
780947357B5BB6383CA.png>
Dave Alberti
414-699-9312
On Nov 20, 2018, at 7:59 PM, Hugh McKay <hgmckay@bellsouth.net> wrote:
Dave,
=C2-
My battery is manually isolated by Breaker 13 shown within the =9Cclo
ud=9D noted as Rev.#1 on the attached one line (better drawing than w
hat I sent previous). All the Breakers mounted on the panel including Break
er 13 are Potter & Brumfield W23 Push Button Thermal circuit breakers that
can also be used as manual isolation switches. I assumed the term =9C
Master Switch=9D as used by Mr. Truemper meant the =9CIgnition
Switch=9D as seen on my one line. With that switch in the =9Cof
f=9D position and Breaker 13 open the voltage to ground on R, B+, and
C each measured 12.7 VDC in stead of 0 VDC. This is the same wiring arrang
ement as shown in the Rotax 912 Installation Manual, page 46 of 66 Dated 19
97 03 26. Unless I am =9Csomewhere lost in translation=9D, If M
r. Truemper has his engine wired according to the Rotax manual (which is th
e same as mine, he should also be reading the voltage to ground on R, B+, a
nd C each as 12+ VDC in stead of 0 VDC
=C2-
Having said all this, have I lost my mind?? According to the attached one l
ine is my electrical system wired correctly????<D29C00CAAAD94829847618F3128
C3F05.jpg>
=C2-
=C2-
Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
=C2-
Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay@bellsouth.net
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10
=C2-
From: Dave Alberti
Sent: Tuesday, November 20, 2018 7:23 PM
Subject: Re: RotaxEngines-List: Rotax 912 UL Rectifier wiring
=C2-
You don=99t show a battery relay to that isolates the battery when al
l switches are off (as in shutdown) which is in the rotax install wiring di
agram. =C2-I believe that is the master that =C2-Truemper=99s spe
aking about.
Dave Alberti
414-699-9312
On Nov 20, 2018, at 3:46 PM, Hugh McKay <hgmckay@bellsouth.net> wrote:
I need some advice by anyone out there who may be able to clear up a questi
on I have concerning checking the output wiring of the standard Rotax 912 r
ectifier used with the 912 UL engine. I have this rectifier on my =C2-All
egro 2000 ELSA (912 UL engine). For additional information I am attaching m
y airplane wiring one line diagram that shows how my rectifier is wired. Al
so I want to make reference to a Blog article authored by Klaus Truemper ti
tled =9C18 December 2012 Testing Rotax 912/914 Generator and Rectifie
r=9D. You can Google the title and read the article.
=C2-
In the section of Mr. Truemper=99s article (Testing Regulator/Rectifi
er) where he states =9CWith the Master switch off: The above test (re
ferring to the previous paragraph) should show 0 voltage for all three case
s. I do not know what Mr. Truemper=99s wiring diagram looked like bec
ause he did not offer one in his article.
=C2-
After reading Mr. Truemper=99s article and because of some perceived
battery charging issues I was having with my airplane I thought I would che
ck my rectifier according to his instructions in the article section titled
(Testing Regulator/Rectifier). All the tests he listed (the same ones I di
d) fell within the values stated in his article except those tested with th
e Master switch =9Coff=9D. In my case, with the Master switch
=9Coff=9D the voltage to ground on R, B+, and C each measured 1
2.7 VDC in stead of 0 VDC.
=C2-
Again I don=99t have Mr. Truemper=99s wiring diagram, but in th
e wiring diagram shown in the Rotax 912 UL engine installation manual their
wiring diagram indicates that there will be regular 12 VDC battery voltage
on R, B+, and C when the master switch is =9Coff=9D.
=C2-
My question is this: Assuming there is a disconnect switch between terminal
C and B+ in the open position (per instruction from Rotax to protect the b
attery from discharge), with the Master switch in the =9Coff=9D
position should I be measuring 12+VDC to ground on R, B+, and C rather tha
n 0 VDC??
=C2-
Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
=C2-
Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay@bellsouth.net
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10
=C2-
<Electrical wiring one-line Diagram.pdf>
=C2-
<D29C00CAAAD94829847618F3128C3F05.jpg>
=C2-
<image1.png>
=C2-
<Allegro 2000 Wiring Sketch.pdf>
<DADA423704E04780947357B5BB6383CA.png>
Message 2
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| Subject: | Re: 912 Bed-Mount bolt torque |
If it's a 8 X 1.25 that's close to a 5/16-18 for me and I wouldn't go
beyond 14 ft lb and use Loctite 243 to keep it tight. The HMM specifies
17.7 ft lb for unlisted M8. I guess that gives you 16 ft lb +/- 1.5 ft lb.
:-}.
Rick
On Thu, Nov 22, 2018 at 10:15 AM edflys2 <edkalau@shaw.ca> wrote:
>
> Have a 912ULS configured with a bed mount. I am trying to determine the
> correct torque for the cap screws that hold the Zenair steel Angle Bracke
ts
> to the bottom of the crank case (Sonex call them "Engine Mount Attach
> Bars"). I find various recommended torque values for the M8 cap screws
as
> high as 26 ft lbs, which seems high for a bolt screwed into an aluminum
> crank case.
>
> Any advise appreciated.
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=485503#485503
>
>
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--
=9CBlessed are the cracked, for they shall let in the light.=9D
Groucho Marx
<http://www.goodreads.com/author/show/43244.Groucho_Marx>
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