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Airdog77
Joined: 24 Nov 2013
Posts: 80
Location: Northern Virginia
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 Posted: Tue Jun 28, 2016 10:16 am Post subject: Z-13/8 Questions |
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Hi Bob,
I'm building a Long-EZ and have a couple of questions on the Z-13/8 architecture.
1. In AEC 12th Ed. Chapter 11-3 you discuss "panel space conservation" and that in the Z diagrams there's an example that shows "avionics master switch controls essential bus connection to main bus, selects an emergency mode essential bus feed directly from battery . . . " I couldn't find any examples of that, but it did make me consider combining the AUX ALT and E-BUS ALT FEED switches into one switch using a 2-10 ON-ON-ON switch. Is there a specific reason that I'm missing that would preclude me from doing so? My thought is that it would refine my focus if my main alternator goes haywire, requiring me then to only concern myself with two actual switches versus three. Plus, there's the added bonus of weight savings and panel space.
2. I found a forum exchange where you discussed keeping feeds off the battery bus no greater than 7A (if fused). Otherwise, the feed should have a pilot controlled disconnect (relay) in local proximity to the bus. Apparently, I missed taking this into account as I designed my electrical system, and am now backtracking a bit to correct it. I wanted to clarify this information since in many of the Z diagrams in the back of the AEC you show a 10A fuel pump being fed off the battery bus. I also wanted to confirm this because I have a couple items requiring 10A feeds that I would like to keep on the battery bus. The first is a fuel pump, which I can throw in a relay no problem. The other feed, however, is for the nose gear actuator. On the gear actuator, the manufacturer's schematic shows the feed coming off the battery bus to a panel mounted 10A circuit breaker (required by manufacturer). I'm a bit stuck on how to design this, especially since there's no included information as to whether the gear actuator feed should be connected off the battery bus at a fused fast-on tab or off the threaded fuseblock post? I'm trying to keep my electrical system as safe, simple and elegant as possible, so I would greatly appreciate your feedback on this.
Regards,
Wade Parton
(building) Long-EZ N916WP
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Airdog
Wade Parton
Building Long-EZ N916WP
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nuckolls.bob(at)aeroelect
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| Posted: Tue Jun 28, 2016 11:56 am Post subject: Z-13/8 Questions |
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At 01:11 PM 6/28/2016, you wrote:
| Quote: | Hi Bob,
I'm building a Long-EZ and have a couple of questions on the Z-13/8 architecture.
1. In AEC 12th Ed. Chapter 11-3 you discuss "panel space conservation" and that in the Z diagrams there's an example that shows "avionics master switch controls essential (ENDURANCE) bus connection to main bus, selects an emergency (PLAN-B . . . we don't have emergencies) mode essential bus feed directly from battery . . . " I couldn't find any examples of that, but it did make me consider combining the AUX ALT and E-BUS ALT FEED switches into one switch using a 2-10 ON-ON-ON switch. |
Not recommended. It's prudent not to
generate signle points of failure for
the e-bus feeds.
| Quote: | | Is there a specific reason that I'm missing that would preclude me from doing so? My thought is that it would refine my focus if my main alternator goes haywire, requiring me then to only concern myself with two actual switches versus three. Plus, there's the added bonus of weight savings and panel space. |
That 'avionics switch' was illustrated to
placate builders deeply steeped in legacy
hangar lore. The original need for an avionics
switch was il-conceived. The REAL need for
any such switch evaporated a few years later
with the incorporation of DO160 design goals
and even less significant with the drop in
avionics power draw paired with more robust
cranking performance of batteries.
None of the z-figures illustrates or suggests
an avionics master switch.
| Quote: | | 2. I found a forum exchange where you discussed keeping feeds off the battery bus no greater than 7A (if fused). Otherwise, the feed should have a pilot controlled disconnect (relay) in local proximity to the bus. Apparently, I missed taking this into account as I designed my electrical system, and am now backtracking a bit to correct it. |
What's on your e-bus? Remember, this is an
ENDURANCE bus . . . crafted and loaded such
that during loss of main alternator, energy
stored in the ship's battery is held in RESERVE
for descent and approach to landing. So if you've
got an SD-8 aux alternator, e-bus loading goals
are on the order of 8A or less. This is done
by operating only those items necessary for
the EN ROUTE phase of flight.
The e-bus first appeared on LongEz aircraft
before Z-13/8. Back then, the design goal was to
reduce EnRoute loads to some value assuring
arrival at airport of intended destination
battery-only. Often these loads added up to
less than 2 amps. Panel lite, nav receiver,
transponder.
With Z-13/8, the nature of e-bus ops changed
dramatically. Now you have an en route budget
on the order of 8A while holding the battery
in reserve. Shoot for 8A or less and don't
worry about the relay.
| Quote: | | I wanted to clarify this information since in many of the Z diagrams in the back of the AEC you show a 10A fuel pump being fed off the battery bus. |
I don't show a fuel pump that DRAWS 10A,
I show a fuel pump that is POWERED through
a feeder protected at 10A.
| Quote: | | I also wanted to confirm this because I have a couple items requiring 10A feeds that I would like to keep on the battery bus. The first is a fuel pump, which I can throw in a relay no problem. |
What is the current draw for this pump?
| Quote: | | The other feed, however, is for the nose gear actuator. On the gear actuator, the manufacturer's schematic shows the feed coming off the battery bus to a panel mounted 10A circuit breaker (required by manufacturer). |
That is an intermittent load . . . lasting
only seconds. So like your starter that draws
a LOT of current, it only uses a few percent
of the battery's stored energy to get the fires
lit off.
| Quote: | | I'm a bit stuck on how to design this, especially since there's no included information as to whether the gear actuator feed should be connected off the battery bus at a fused fast-on tab or off the threaded fuseblock post? |
Your nose gear actuator could draw lots of
current but it's only for a few seconds so the
ENERGY required is minimal. Wire it to a fast-on
location at the battery bus fuse block. Shucks, you can wire
the nose gear up with 12AWG driven by a 20 A fuse
if there's any concern for nuisance tripping the
fuse. I would do some testing on the ground
to put a rough measure on the motor's inrush
characteristics. What kind of information do you
have on the motor used in the gear assembly?
Does it have a lable with a manufacturer's name
and part number?
| Quote: | I'm trying to keep my electrical system as safe, simple and elegant as possible, so I would greatly appreciate your feedback on this.
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No problem, it's what we do here. If you're
putting Z-13/8 in an Ez, then tie all your
alternator feeds to the system at the HOT
size of the starter contactor which should
be on the firewall. What size wires are you
running aft for starter feed and ground?
Make us a list of all your fuses, what they
feed and which bus drives them.
Bob . . .
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Airdog77
Joined: 24 Nov 2013
Posts: 80
Location: Northern Virginia
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| Posted: Tue Jun 28, 2016 3:17 pm Post subject: Re: Z-13/8 Questions |
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Bob,
Roger on NOT combining the AUX ALT and E-BUS ALT FEED switches into one switch. It does make me curious though what would happen if either of those switches becomes in-op, since there would still be no way to revert to the SD-8 backup ALT, correct?
| Quote: |
What's on your e-bus? |
This is what I currently have on my E-BUS:
E-Bus Relay/SD-8 Relay/VReg/OV 0.3A
ElectroAir Electronic Ignition System Coil 0.8A
Electronic Ignition System Controller 0.8A
EFIS GRT HXr - PFD 1.5A
EFIS GRT Mini-X MFD 0.3A
Engine Mgt System Module - GRT 0.2A
TruTrak ADI 0.5A
Trig TT22 Transponder Mode S 0.4A
Trig TY91 Radio - COM1 0.2A
Radenna SkyRadar-DX ADSB Receiver 0.4A
Fuel Computer 0.4A
MGL RTC-2 Clock 0.1A
USB Hub 0.4A
Nose Gear Auto Gear Extension 0.1A
Nav Lights 0.4A
TRIO Autopilot Control Head 0.5A
Trio A/P Servos (~2A transient)
Total nominal draw on E-BUS/SD-8: 7.9 amps (not including transient loads).
Also, The numbers above either came out of the manuals or from discussions with the manufacturers.
I do currently have an S704-1 Relay wired into place between the battery bus and E-Bus.
| Quote: | | What is the current draw for this pump? |
Just under 5A according to the folks at EFII. According to them, a 16AWG wire fused at 10A from the battery bus to the panel switch, then 16AWG to the pump sitting just forward of the firewall would work fine.
| Quote: |
What kind of information do you
have on the motor used in the gear assembly?
Does it have a lable with a manufacturer's name
and part number? |
The nose gear actuator is under a cover right now that is difficult to get to, but from my build pictures I found that on the motor cover it states:
| Quote: | | Thomson Saginaw Ball Screw Company, Inc., Performance Pak |
And from looking at the manufacturer's website, it looks as if this is the Electrak 10 series motor. The nose gear actuator motor is actually part of the EZNoseLift electric nose gear system. The purpose for the 10A CB is that in a fiberglass plane like the Long-EZ it offers some protection if the up-travel microswitch fails and the nose gear continues to travel up into the nose wheel well. After some minor crushing the 10A CB is designed to pop and thus save the rest of nose from any further damage. I checked with the manufacturer and he recommended running a 16-AWG wire from the battery bus to the 10CB on the panel.
| Quote: | What size wires are you
running aft for starter feed and ground? |
Planning on using the Super-4-CCA copper clad aluminum. This was recommended to me by a number of EZ drivers that are currently using it and are quite happy with it.
I'll work on compiling that list of fuses, feeds and busses.
Thanks Bob!
-Wade
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_________________
Airdog
Wade Parton
Building Long-EZ N916WP
www.longezpush.com |
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nuckolls.bob(at)aeroelect
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| Posted: Tue Jun 28, 2016 5:20 pm Post subject: Z-13/8 Questions |
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At 06:17 PM 6/28/2016, you wrote:
| Quote: | --> AeroElectric-List message posted by: "Airdog77" <Airdog77(at)gmail.com>
Bob,
Roger on NOT combining the AUX ALT and E-BUS ALT FEED switches into one switch. It does make me curious though what would happen if either of those switches becomes in-op, since there would still be no way to revert to the SD-8 backup ALT, correct? |
Not at all. Recall that the Plan-B for inop main
alternator is . . .
Ebus Alt Feed Switch . . . closed.
Aux alternator Switch . . . ON
Main alternator/battery contactor switch . . . . OPEN
This series of actions supports the e-bus
DIRECTLY from the battery, supports the battery
with 8A of engine driven energy, relieves the
system of parasitic battery contactor loads and
potentially parasitic alternator field loads.
The main bus goes dark.
This DOES not preclude the pilot from re-closing
the battery contactor to bring the main bus back
up . . . which brings the e-bus up as well through
the normal feed diode.
But keep in mind that ONE failure is rare,
in the interval defined by fuel aboard for engine
endurance. DUAL failures are exceedingly rare.
Hence, there are NO single failures of Z-13/8
that put the pilot in an uncomfortable condition.
Bob . . .
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nuckolls.bob(at)aeroelect
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| Posted: Tue Jun 28, 2016 6:46 pm Post subject: Z-13/8 Questions |
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| Quote: |
This is what I currently have on my E-BUS:
E-Bus Relay/SD-8 Relay/VReg/OV 0.3A
ElectroAir Electronic Ignition System Coil 0.8A
Electronic Ignition System Controller 0.8A
EFIS GRT HXr - PFD 1.5A
EFIS GRT Mini-X MFD 0.3A
Engine Mgt System Module - GRT 0.2A
TruTrak ADI 0.5A
Trig TT22 Transponder Mode S 0.4A
Trig TY91 Radio - COM1 0.2A
Radenna SkyRadar-DX ADSB Receiver 0.4A
Fuel Computer 0.4A
MGL RTC-2 Clock 0.1A
USB Hub 0.4A
Nose Gear Auto Gear Extension 0.1A
Nav Lights 0.4A
TRIO Autopilot Control Head 0.5A
Trio A/P Servos (~2A transient)
Total nominal draw on E-BUS/SD-8: 7.9 amps (not including transient loads). |
Okay, looks like the SD8 is good
| Quote: | Also, The numbers above either came out of the manuals or from discussions with the manufacturers.
I do currently have an S704-1 Relay wired into place between the battery bus and E-Bus. |
that could go away . . .
| Quote: | > What is the current draw for this pump?
Just under 5A according to the folks at EFII. According to them, a 16AWG wire fused at 10A from the battery bus to the panel switch, then 16AWG to the pump sitting just forward of the firewall would work fine. |
Is this a back up pump or does it run all the time?
| Quote: | > Thomson Saginaw Ball Screw Company, Inc., Performance Pak
And from looking at the manufacturer's website, it looks as if this is the Electrak 10 series motor. The nose gear actuator motor is actually part of the EZNoseLift electric nose gear system. The purpose for the 10A CB is that in a fiberglass plane like the Long-EZ it offers some protection if the up-travel microswitch fails and the nose gear continues to travel up into the nose wheel well. After some minor crushing the 10A CB is designed to pop and thus save the rest of nose from any further damage. I checked with the manufacturer and he recommended running a 16-AWG wire from the battery bus to the 10CB on the panel. |
Hmmmm . . . IVO Props do a similar thing to
manage the stalled motor condition . . . not
very sanitary. If these are ball-screw actuators,
theres is potential for large forces on
the screw as a product of both stall torque and
dynamic torque when bringing the rotating armature
mass to an abrupt halt.
Have there been instances of limit switch failure?
| Quote: | > What size wires are you
> running aft for starter feed and ground?
Planning on using the Super-4-CCA copper clad aluminum. This was recommended to me by a number of EZ drivers that are currently using it and are quite happy with it.
I'll work on compiling that list of fuses, feeds and busses. |
Looking forward to it . . .
Bob . . .
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Airdog77
Joined: 24 Nov 2013
Posts: 80
Location: Northern Virginia
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| Posted: Tue Jun 28, 2016 8:45 pm Post subject: Re: Z-13/8 Questions |
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Bob,
I'm glad I asked the question!
| Quote: | Not at all. Recall that the Plan-B for inop main
alternator is . . .
Ebus Alt Feed Switch . . . closed.
Aux alternator Switch . . . ON
Main alternator/battery contactor switch . . . . OPEN |
For some reason I had this process exactly reversed... some vital info to know right there!
Also good to know on the relay between the battery bus and E-bus: I'll remove it.
| Quote: |
Is this a back up pump or does it run all the time? |
It's a back up pump to the engine driven fuel pump. It's only on during takeoffs and landings, and as a backup if the mechanical fuel pump croaks.
| Quote: |
Have there been instances of limit switch failure? |
I haven't heard of any limit switch failures, and I've been working this project for over 5 years. I did get into the manual and here's the warning, which shows that a failure of the micro-switch is protected more by the mechanical configuration of the actuator, in conjunction with a CB, than any crunching of fiberglass. Forgive my earlier dramatic paraphrasing on how this thing works:
"Warning:
The actuator is capable of 3000 lbs. of straight line lifting force that
will cause damage and injury even when protected by the slip clutch
and the circuit breaker. In case of micro switch failure or
misadjustment, the over travel in the up position is about .15” at the
actuator. The internal rubber shock cushion will absorb this and the
actuator will reach its mechanical limit and pop the breaker. This
feature will protect the aircraft structure from damage."
Thanks again Bob!
Regards,
-Wade
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Airdog
Wade Parton
Building Long-EZ N916WP
www.longezpush.com |
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JOHN TIPTON
Joined: 17 Sep 2006
Posts: 239
Location: Torquay - England
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| Posted: Tue Jun 28, 2016 10:39 pm Post subject: Z-13/8 Questions |
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Hi Bob
Isn't 'closed' - 'ON' --- (and of course 'open' being 'OFF')
You used both 'styles' or am I wrong
John
Sent from my iPad
----x--O--x----
On 29 Jun 2016, at 02:09 am, "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:
| Quote: | At 06:17 PM 6/28/2016, you wrote:
| Quote: | --> AeroElectric-List message posted by: "Airdog77" <Airdog77(at)gmail.com (Airdog77(at)gmail.com)>
Bob,
Roger on NOT combining the AUX ALT and E-BUS ALT FEED switches into one switch. It does make me curious though what would happen if either of those switches becomes in-op, since there would still be no way to revert to the SD-8 backup ALT, correct? |
Not at all. Recall that the Plan-B for inop main
alternator is . . .
Ebus Alt Feed Switch . . . closed.
Aux alternator Switch . . . ON
Main alternator/battery contactor switch . . . . OPEN
This series of actions supports the e-bus
DIRECTLY from the battery, supports the battery
with 8A of engine driven energy, relieves the
system of parasitic battery contactor loads and
potentially parasitic alternator field loads.
The main bus goes dark.
This DOES not preclude the pilot from re-closing
the battery contactor to bring the main bus back
up . . . which brings the e-bus up as well through
the normal feed diode.
But keep in mind that ONE failure is rare,
in the interval defined by fuel aboard for engine
endurance. DUAL failures are exceedingly rare.
Hence, there are NO single failures of Z-13/8
that put the pilot in an uncomfortable condition.
Bob . . .
|
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nuckolls.bob(at)aeroelect
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| Posted: Wed Jun 29, 2016 4:53 am Post subject: Z-13/8 Questions |
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At 01:36 AM 6/29/2016, you wrote:
| Quote: | Hi Bob
Isn't 'closed' - 'ON' --- (and of course 'open' being 'OFF')
You used both 'styles' or am I wrong |
yes
open/off closed/on
Bob . . .
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kenryan
Joined: 20 Oct 2009
Posts: 426
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| Posted: Sat Jul 02, 2016 4:38 pm Post subject: z-13/8 questions |
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Regarding drawing Z-13/8 ...
1. Why is there a 30 amp inline fuse on the 14 gauge wire coming from the 8 amp dynamo?
2. Why doesn't the 4AWG cable connect to the battery side of the battery contactor?
Thanks,
Ken Ryan
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user9253
Joined: 28 Mar 2008
Posts: 1922
Location: Riley TWP Michigan
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| Posted: Sat Jul 02, 2016 6:14 pm Post subject: Re: Z-13/8 Questions |
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If the over-voltage module shorts out, it is desired that the 2 amp circuit breaker trip before the fuse blows. A larger size fuse will take longer to blow.
There is a 4 awg wire connected to the battery side of the battery contactor. I do not understand the question.
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kenryan
Joined: 20 Oct 2009
Posts: 426
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| Posted: Sat Jul 02, 2016 6:43 pm Post subject: Z-13/8 Questions |
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Thanks Joe. I was thinking 30 amps was too high for 14 gauge but I now see that it's not. The other question is why not run the big cable to the starter from the battery side of the contactor? That way the engine could be started in the event of battery contactor failure. Is it because cutting current to that wire when the contactor is turned off is considered more important than being able to start the engine if the contactor fails? That would make sense I guess for forced landings, etc. But not for getting maximum voltage to the starter. The reason I ask is because the Rotax 914 installation manual shows the starter wire going to the battery side of the battery contactor. And it does seem like it would make sense to maximize voltage getting to the starter.
On Sat, Jul 2, 2016 at 6:14 PM, user9253 <fransew(at)gmail.com (fransew(at)gmail.com)> wrote:
| Quote: | --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)>
If the over-voltage module shorts out, it is desired that the 2 amp circuit breaker trip before the fuse blows. A larger size fuse will take longer to blow.
There is a 4 awg wire connected to the battery side of the battery contactor. I do not understand the question.
--------
Joe Gores
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user9253
Joined: 28 Mar 2008
Posts: 1922
Location: Riley TWP Michigan
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| Posted: Sun Jul 03, 2016 4:38 am Post subject: Re: Z-13/8 Questions |
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A 30 amp fuse is normally too high for protecting a #14 wire. There are two purposes for circuit protection, overload and short circuits. Since a PM dynamo is self current limiting, overload protection does not need to the provided. But short circuit protection does. The battery and the rest of the electrical system needs to be protected against the PM dynamo circuit shorting out. A 30 amp fuse will definitely blow when a 14 awg wire shorts out. The event will happen so quickly that the tefzel insulation will not get hot enough to be damaged.
B and C provides a schematic that is wired as you suggested. In fact, there is no battery contactor at all.
http://www.bandc.aero/pdfs/420-506_REVB.pdf
Most aircraft are wired with the battery contactor and starter contactor in series. One advantage is being able to shut off the battery contactor if the starter contactor gets stuck closed. I understand Rotax's reasoning. There is more than one way to wire an airplane. Like other design considerations, compromises need to be made. The advantage of one feature causes a disadvantage someplace else.
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kenryan
Joined: 20 Oct 2009
Posts: 426
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| Posted: Sun Jul 03, 2016 7:20 am Post subject: Z-13/8 Questions |
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Thanks Joe, especially for the explanation regarding overload and short circuit. I never clearly understood that before. Here's another question:
With the Rotax the rotary keyed ignition switch is not allowed. Independent toggles for the ignitions are clearly specified. Given that, what would be the options for inserting a keyed switch to prevent unauthorized starting? The only thing I have come up with is to put it in series with the battery contactor (given that the starter cable is connected to the output side of that contactor). If I moved the starter cable to the battery side of the contactor, where might I use a keyed switch?
Ken
On Sun, Jul 3, 2016 at 4:38 AM, user9253 <fransew(at)gmail.com (fransew(at)gmail.com)> wrote:
| Quote: | --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)>
A 30 amp fuse is normally too high for protecting a #14 wire. There are two purposes for circuit protection, overload and short circuits. Since a PM dynamo is self current limiting, overload protection does not need to the provided. But short circuit protection does. The battery and the rest of the electrical system needs to be protected against the PM dynamo circuit shorting out. A 30 amp fuse will definitely blow when a 14 awg wire shorts out. The event will happen so quickly that the tefzel insulation will not get hot enough to be damaged.
B and C provides a schematic that is wired as you suggested. In fact, there is no battery contactor at all.
http://www.bandc.aero/pdfs/420-506_REVB.pdf
Most aircraft are wired with the battery contactor and starter contactor in series. One advantage is being able to shut off the battery contactor if the starter contactor gets stuck closed. I understand Rotax's reasoning. There is more than one way to wire an airplane. Like other design considerations, compromises need to be made. The advantage of one feature causes a disadvantage someplace else.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=457672#457672
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user9253
Joined: 28 Mar 2008
Posts: 1922
Location: Riley TWP Michigan
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| Posted: Sun Jul 03, 2016 8:20 am Post subject: Re: Z-13/8 Questions |
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Ken, assuming that you are installing a starter contactor, how about wiring it as shown in Z13/8?
Battery, Battery Contactor, Starter Contactor, Starter
Replace the push button switch in Z13/8 with a momentary key switch like Mouser part number 611-Y208122A203NQ
Ignore the Mouser Switch Function description. The C&K data sheet shows that the DPDT switch can be wired to function as desired.
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Joe Gores
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user9253
Joined: 28 Mar 2008
Posts: 1922
Location: Riley TWP Michigan
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| Posted: Sun Jul 03, 2016 8:29 am Post subject: Re: Z-13/8 Questions |
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If your starter contactor does not have an internal diode, install an exterior one with the arrow pointing towards positive. The banded end of a diode is the end of the diode that the arrow points towards. A diode will protect the start switch from arcing.
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gilles.thesee(at)free.fr
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| Posted: Sun Jul 03, 2016 11:18 am Post subject: Z-13/8 Questions |
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Le 03/07/2016 à 17:17, Ken Ryan a écrit :
| Quote: |
With the Rotax the rotary keyed ignition switch is not allowed. Independent toggles for the ignitions are clearly specified.
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Hi Ken and all,
Didn't know about that.
Maybe it concerns the latest engines. Or maybe it is in the new installation documents, but as Rotax didn't change the engines already flying, I would not lose sleep on the keyswitch vs separate switches problem.
Hundreds of airplanes have been flying for years with a standard ignition keyswitch for their Rotax without the slightest issue.
I'd even state that the Rotax circuit wiring suggestions are to be taken with a grain of salt, especially concerning the 914.
--
Best regards,
Gilles
http://contrails.free.fr
http://lapierre.skunkworks.free.fr
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kenryan
Joined: 20 Oct 2009
Posts: 426
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| Posted: Sun Jul 03, 2016 11:25 am Post subject: Z-13/8 Questions |
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Thanks Joe, good idea.
On Sun, Jul 3, 2016 at 8:20 AM, user9253 <fransew(at)gmail.com (fransew(at)gmail.com)> wrote:
| Quote: | --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)>
Ken, assuming that you are installing a starter contactor, how about wiring it as shown in Z13/8?
Battery, Battery Contactor, Starter Contactor, Starter
Replace the push button switch in Z13/8 with a momentary key switch like Mouser part number 611-Y208122A203NQ
Ignore the Mouser Switch Function description. The C&K data sheet shows that the DPDT that can be wired to function as desired.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=457674#457674
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eferrer" target="_blank">http://forums.matronics.com
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errer" target="_blank">http://wiki.matronics.com
===========
b Site -
-Matt Dralle, List Admin.
rel="noreferrer" target="_blank">http://www.matronics.com/contribution
===========
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kenryan
Joined: 20 Oct 2009
Posts: 426
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| Posted: Sun Jul 03, 2016 11:31 am Post subject: Z-13/8 Questions |
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Thanks Gilles. As I tend to be biased towards the manufacturer when it comes to guidance, I am referring heavily to the Rotax 914 installation instructions. Can you tell me specifically which areas that you feel are suspect? If you could do that it would help me to evaluate their "suggestions" against my installation.
On Sun, Jul 3, 2016 at 10:53 AM, GTH <gilles.thesee(at)free.fr (gilles.thesee(at)free.fr)> wrote:
| Quote: | Le 03/07/2016 à 17:17, Ken Ryan a écrit :
| Quote: |
With the Rotax the rotary keyed ignition switch is not allowed. Independent toggles for the ignitions are clearly specified.
|
Hi Ken and all,
Didn't know about that.
Maybe it concerns the latest engines. Or maybe it is in the new installation documents, but as Rotax didn't change the engines already flying, I would not lose sleep on the keyswitch vs separate switches problem.
Hundreds of airplanes have been flying for years with a standard ignition keyswitch for their Rotax without the slightest issue.
I'd even state that the Rotax circuit wiring suggestions are to be taken with a grain of salt, especially concerning the 914.
--
Best regards,
Gilles
http://contrails.free.fr
http://lapierre.skunkworks.free.fr
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user9253
Joined: 28 Mar 2008
Posts: 1922
Location: Riley TWP Michigan
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| Posted: Sun Jul 03, 2016 11:50 am Post subject: Re: Z-13/8 Questions |
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I agree with Gilles. What difference does it make if both ignition switches and start switch are within one housing or are independent switches? Unless you consider the switch handle being a common point of failure. Advantage of individual switches are less cost and easier to replace and troubleshoot.
| Quote: | | I'd even state that the Rotax circuit wiring suggestions are to be taken with a grain of salt |
Agree, how about the warning not to run the engine with regulator terminal C not connected or the regulator will self destruct?
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gilles.thesee(at)free.fr
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| Posted: Mon Jul 04, 2016 4:57 am Post subject: Z-13/8 Questions |
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Le 03/07/2016 à 21:30, Ken Ryan a écrit :
| Quote: | Thanks Gilles. As I tend to be biased towards the manufacturer when it comes to guidance, I am referring heavily to the Rotax 914 installation instructions. Can you tell me specifically which areas that you feel are suspect? If you could do that it would help me to evaluate their "suggestions" against my installation.
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Hi Ken and all,
It took me some time to download and peruse the latest 914 Installation Manual (February 2015).
Concerning the ignition switches, it seems there has been no changes since the 1996 version that was current when we wired our project. The manual just mentions
"Type : two separate, suitable on-off switches" (page 114 newer edition)
The Rotax 914 relies on two electrical pumps to keep running.
Rotax suggests to feed the main pump from the voltage rectifier/regulator, and the aux pump from the main bus.
If the regulator fails - not a rare occurence - you are left with only the aux pump and the battery to stay aloft.
I feel a critical pump should run direct from a battery bus.
--
Best regards,
Gilles
http://contrails.free.fr
http://lapierre.skunkworks.free.fr
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