Matronics Email Lists :: View topic - kitfox /rotax 912 wiring diagram (variation on Z-16)

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

kitfox /rotax 912 wiring diagram (variation on Z-16)

Matronics Email Lists Forum Index -> AeroElectric-List

View previous topic :: View next topic

Author Message

uuccio(at)gmail.com
Guest

Posted: Tue Nov 26, 2013 2:38 pm Post subject: kitfox /rotax 912 wiring diagram (variation on Z-16)

Hi Folks,

I’ve finished a CAD drawing of the electrical diagram such as it currently exists on my Rotax 912 powered Kitfox (Kitfox Diagram 0.6.pdf/dwg).    

From reading through Bob’s materials and from previous exchanges on the list, I’ve come up with the following changes which I think are pretty standard:

<![if !supportLists]>-         <![endif]>Eliminate the Master CB (I had put it there following the diagram in the Rotax installation manual)

<![if !supportLists]>-         <![endif]>Make the Avionics bus the E-bus and feed it via a diode instead of via the Avionics Master Switch

<![if !supportLists]>-         <![endif]>Eliminate the Avionics CB and Avionics Master Switch and use the switch as an Alternate Feed for the E-bus

<![if !supportLists]>-         <![endif]>Eliminate the Alternator Light and rewire it as a “Starter On Warning Light”

<![if !supportLists]>-         <![endif]>Create a Battery bus for things like clock, panel lighting, etc

This leads to Kitfox Proposed Diagram 1.23.pdf/dwg which I am submitting for comments/suggestions.   It’s essentially a version of Z-16 with the following differences:

<![if !supportLists]>-         <![endif]>Ignition is via a momentary push-button whereas the Off/BAT/BAT+ALT modes are selected via an On-OFF-On Key switch.  This is more of an inheritance than a conscious choice… if I had to do things again I’d probably use the S700-2-10 switch as per Z-16 and the Key Switch for the mags.

<![if !supportLists]>-         <![endif]>A starter ON warning light was fitted

<![if !supportLists]>-         <![endif]>The low/high voltage monitoring is achieved via a LED with a tiny voltage sensitive auto-dimming circuit (Eclipse, sold by Sparkbright in the UK for approx $15).  This is green when the main bus voltage is between 13.2 and 15.2 volts, and various combinations of amber, alternating green and red or flashing red for over or under-voltage conditions. Sparkbright claims the calibration is better than 0.03 volts and I have not been able to disprove this.  

<![if !supportLists]>-         <![endif]>There are some extra features represented (such as the wiring of the two joysticks (Infinity Grips, Infinity Aerospace) and the extra 22,000 uF capacitor for the fuel pump (as per Rotax installation manual).

I’ve also attached a load analysis (Load Analysis.xls).

Thanks in advance for your comments!

Regards,

Sacha

Kitfox_Proposed_Diagram_1.23.dwg

Description:

Download

Filename:

Kitfox_Proposed_Diagram_1.23.dwg

Filesize:

86.18 KB

Downloaded:

573 Time(s)

Kitfox_Proposed_Diagram_1.23.pdf

Description:

Download

Filename:

Kitfox_Proposed_Diagram_1.23.pdf

Filesize:

88.13 KB

Downloaded:

687 Time(s)

Kitfox_Electrical_Diagram_0.6.dwg

Description:

Download

Filename:

Kitfox_Electrical_Diagram_0.6.dwg

Filesize:

84.18 KB

Downloaded:

557 Time(s)

Kitfox_Electrical_Diagram_0.6.pdf

Description:

Download

Filename:

Kitfox_Electrical_Diagram_0.6.pdf

Filesize:

75.52 KB

Downloaded:

507 Time(s)

Load_Analysis.xlsx

Description:

Download

Filename:

Load_Analysis.xlsx

Filesize:

31.89 KB

Downloaded:

492 Time(s)

user9253

Joined: 28 Mar 2008
Posts: 1938
Location: Riley TWP Michigan

Posted: Wed Nov 27, 2013 6:30 am Post subject: Re: kitfox /rotax 912 wiring diagram (variation on Z-16)

Sacha,

The output of the dynamo goes through a 5 amp circuit breaker which is too small for a 20 amp dynamo.

  The 25 amp main circuit breaker is a single point of failure.  When it opens, everything electrical stops working.

  To fix the above two problems, use the 25 amp circuit breaker for the dynamo circuit.  Do not install any main circuit breaker.  The pilot can shut off the master relay in case of smoke in the cockpit.

  The 20 amp avionics circuit breaker is another single point of failure.  Replace it with a wire.

  I see no reason to have the starter switch on the control stick unless the pilot intends to make frequent engine starts while flying.  It is only a matter of time before the start button is accidentally pushed when the engine is already running.

 If anyone disagrees with the above, please speak up.  It will not hurt my feelings and I want Sacha to have good advice.

Joe

_________________
Joe Gores

user9253

Joined: 28 Mar 2008
Posts: 1938
Location: Riley TWP Michigan

Posted: Wed Nov 27, 2013 6:41 am Post subject: Re: kitfox /rotax 912 wiring diagram (variation on Z-16)

Sacha,

I was looking at the wrong schematic, Kitfox Diagram 0.6.pdf, my mistake.

I should have been looking at Kitfox_Proposed_Diagram_1.23.pdf.

  Even so, the dynamo output is still going though a 5 amp breaker.  And the start switch is still on the control stick.

Joe

_________________
Joe Gores

user9253

Joined: 28 Mar 2008
Posts: 1938
Location: Riley TWP Michigan

Posted: Fri Nov 29, 2013 11:01 am Post subject: Re: kitfox /rotax 912 wiring diagram (variation on Z-16)

 	  Quote: 	
		  By replaced, do you mean I should add a fuse between the Dynamo and the Voltage regulator? 	


No

 	  Quote: 	
		  I’m confused… I thought the b-lead is wire that goes between the dynamo and the voltage regulator. How can it be connected to the battery contactor? 	


The two yellow wires from the dynamo carry AC to the voltage rectifier / regulator.  The yellow wires connect to "G" terminals.  I assume the "G" stands for Generator.  Notice the letter "B" on the regulator connector.  I consider the "B" lead to be the wire that connects the output of the regulator to the aircraft electrical system.  This wire needs to be protected against short circuits at the battery end with a fuse or circuit breaker.  The advantage of using a fuse is that it can be located on the engine side of the firewall adjacent to and connected to the load side of the master relay.  Since the maximum output of the Rotax dynamo is 20 amps, it is unlikely that a 30 amp fuse will nuisance blow.

 	  Quote: 	
		  the ALT breaker. . . . seems to limiting the current that the dynamo can supply . . 	


The output of an alternator is limited by the load or by the capacity of the alternator, whichever is less.  Since the load will usually be more than 5 amps, a 5 amp circuit breaker will trip and disable the charging system.  The charging system will never work at all if wired per the schematic.

Joe

_________________
Joe Gores

uuccio(at)gmail.com
Guest

Posted: Fri Nov 29, 2013 3:46 pm Post subject: kitfox /rotax 912 wiring diagram (variation on Z-16)

 

 	  Quote: 	
		   Iâ€™m confusedâ€¦ I thought the b-lead is wire that goes between the dynamo and the voltage regulator. How can it be connected to the battery contactor?  

The two yellow wires from the dynamo carry AC to the voltage rectifier / regulator.  The yellow wires connect to "G" terminals.  I assume the "G" stands for Generator.  Notice the letter "B" on the regulator connector.  I consider the "B" lead to be the wire that connects the output of the regulator to the aircraft electrical system.  This wire needs to be protected against short circuits at the battery end with a fuse or circuit breaker.  The advantage of using a fuse is that it can be located on the engine side of the firewall adjacent to and connected to the load side of the master relay.  Since the maximum output of the Rotax dynamo is 20 amps, it is unlikely that a 30 amp fuse will nuisance blow.  
	


  

Ah!  I got it!  Here is the revised diagram 1.24 (it needs to be cleaned up but at least now I think it is correct).  

  

 	  Quote: 	
		   the ALT breaker. . . . seems to limiting the current that the dynamo can supply . .   

The output of an alternator is limited by the load or by the capacity of the alternator, whichever is less.  Since the load will usually be more than 5 amps, a 5 amp circuit breaker will trip and disable the charging system.  The charging system will never work at all if wired per the schematic.  
	


Joe  

  

Absolutely.  The diagram made no sense at all.  In fact, I think I must have drawn the diagram wrong because the aircraft has flown some 40 hours without the ALT breaker ever tripping.  Anyway, I think I've got it now.  Thank you sir!  

 <<...>>  <<...>>

Kitfox_Proposed_Diagram_1.24.dwg

Description:

Download

Filename:

Kitfox_Proposed_Diagram_1.24.dwg

Filesize:

86.03 KB

Downloaded:

529 Time(s)

Kitfox_Proposed_Diagram_1.24.pdf

Description:

Download

Filename:

Kitfox_Proposed_Diagram_1.24.pdf

Filesize:

87.59 KB

Downloaded:

470 Time(s)

user9253

Joined: 28 Mar 2008
Posts: 1938
Location: Riley TWP Michigan

Posted: Fri Nov 29, 2013 7:30 pm Post subject: Re: kitfox /rotax 912 wiring diagram (variation on Z-16)

OK, you have the dynamo working now.  I see no other major mistakes.  I would not have all of those buttons on the control stick because I know that I would get them mixed up and push the wrong one.  But that is a matter of personal preference.  In the lower right hand corner of the drawing is a 22,000 microfarad capacitor that is connected between ground and the contactors.  I do not think that capacitor is needed.  It does not hurt anything, but is one more thing that could fail.

Joe

_________________
Joe Gores

uuccio(at)gmail.com
Guest

Posted: Sat Nov 30, 2013 2:18 am Post subject: kitfox /rotax 912 wiring diagram (variation on Z-16)

In the lower right hand corner of the drawing is a 22,000

microfarad capacitor that is connected between ground and the contactors.  I

do not think that capacitor is needed.  It does not hurt anything, but is

one more thing that could fail.

		

The Rotax 912 installation manual recommends having a capacitor in parallel

with the fuel pump.  Electrically I guess it is in parallel... Does it make

any difference whether I leave it as it is or should I connect it like this:

winmail.dat

Description:

Download

Filename:

winmail.dat

Filesize:

3.31 KB

Downloaded:

881 Time(s)

user9253

Joined: 28 Mar 2008
Posts: 1938
Location: Riley TWP Michigan

Posted: Sat Nov 30, 2013 5:29 am Post subject: Re: kitfox /rotax 912 wiring diagram (variation on Z-16)

Sacha,

Without a winmail program, I was unable to open the winmail.dat file.

To reduce electrical noise from the fuel pump, the capacitor should be located at the fuel pump and connected to the positive and negative wires of the fuel pump.  I assume that is what you have done in the winmail.dat file.

  In your original drawing, yes, the capacitor is in parallel with the fuel pump in a roundabout way.  But when trying to suppress electrical noise, it is better to keep wires short.

Joe

_________________
Joe Gores

uuccio(at)gmail.com
Guest

Posted: Sat Nov 30, 2013 1:33 pm Post subject: kitfox /rotax 912 wiring diagram (variation on Z-16)

 	  Quote: 	
		   To reduce electrical noise from the fuel pump, the capacitor should be located at the fuel pump and connected to the positive and negative wires of the fuel pump.  I assume that is what you have done in the winmail.dat file. Joe Gores


	


Yes it is. But I thought that the capacitor in parallel with the fuel pump was to facilitate the starting of the pump not to reduce noise. 



Sacha

uuccio(at)gmail.com
Guest

Posted: Tue Dec 03, 2013 11:10 am Post subject: kitfox /rotax 912 wiring diagram (variation on Z-16)

 	  Quote: 	
		   I have not heard reports of audio noise from fuel pumps, but installed the capacitor per instructions for my RV-12. Joe


	


I alway thought of the capacitor as being there to balance out the inductance of the motor thus helping it to start and stop without creating large voltage drops in the circuit.  I suppose this might also be the rationale for the noise reduction. 



In my garden I have a 130 ft well with a large 230VAC electrical pump submersed in the water at the bottom of the well. I can't remember the wattage, I think it was around 1500W.  I noticed that the electrician installed a capacitor in parallel with the pump and I remember that it helped the starting of the pump. 



Sacha

jluckey(at)pacbell.net
Guest

Posted: Tue Dec 03, 2013 12:14 pm Post subject: kitfox /rotax 912 wiring diagram (variation on Z-16)

Capacitors are used to help start single phase AC motors.  They are used to 'fake' a second phase to help the motor start turning.

DC motors are different animals and do not require starting capacitors.

Sometimes very small capacitors are installed across DC motors to help filter the noise caused by brushes.

        From: Sacha <uuccio(at)gmail.com>

 To: "aeroelectric-list(at)matronics.com" <aeroelectric-list(at)matronics.com> 

 Sent: Tuesday, December 3, 2013 11:09 AM

 Subject: Re: Re: kitfox /rotax 912 wiring diagram (variation on Z-16)

 --> AeroElectric-List message posted by: Sacha <uuccio(at)gmail.com (uuccio(at)gmail.com)>

 	  Quote: 	
		   I have not heard reports of audio noise from fuel pumps, but installed the capacitor per instructions for my RV-12. Joe

I alway thought of the capacitor as being there to balance out the inductance of the motor thus helping it to start and stop without creating large voltage drops in the circuit.  I suppose this might also be the rationale for the noise reduction. 

In my garden I have a 130 ft well with a large 230VAC electrical pump submersed in the water at the bottom of the well. I can't remember the wattage, I think it was around 1500W.  I noticed that the electrician installed a capacitor in parallel with the pump and I remember that it helped the starting of the pump. 

Sacha  * The Builder's Bookstore www.homebuilt;     * Race Consulting ww                     &nbs======================

 [quote][b]

uuccio(at)gmail.com
Guest

Posted: Tue Dec 03, 2013 11:34 pm Post subject: kitfox /rotax 912 wiring diagram (variation on Z-16)

Thanks Jeff for shedding light on this. It still leaves a question mark over Rotax's recommendation for installing a capacitor. Maybe I'll ask my German speaking ex-Bosch engineer friend to give the Rotax headquarters a call. He may be able to get some sense out of them or at least an indication of what their rationale was when they included this recommendation in the manual. 



On Dec 3, 2013, at 21:14, Jeff Luckey <jluckey(at)pacbell.net (jluckey(at)pacbell.net)> wrote:

[quote]Capacitors are used to help start single phase AC motors.  They are used to 'fake' a second phase to help the motor start turning.

DC motors are different animals and do not require starting capacitors.

Sometimes very small capacitors are installed across DC motors to help filter the noise caused by brushes.

[b]

uuccio(at)gmail.com
Guest

Posted: Wed Dec 04, 2013 10:06 am Post subject: kitfox /rotax 912 wiring diagram (variation on Z-16)

Bob, what's a PM machine?

Sacha



On Dec 4, 2013, at 16:00, "nuckollsr" <bob.nuckolls(at)aeroelectric.com> wrote:



 	  Quote: 	
		   I'd love to put one of the larger PM machines on the test bench with a Rotax-Ducatti R-R

user9253

Joined: 28 Mar 2008
Posts: 1938
Location: Riley TWP Michigan

Posted: Wed Dec 04, 2013 2:23 pm Post subject: Re: kitfox /rotax 912 wiring diagram (variation on Z-16)

 	  Quote: 	
		  what's a PM machine? 	


Most likely Permanent Magnet alternator, aka dynamo.

_________________
Joe Gores

Display posts from previous:

	Matronics Email Lists Forum Index -> AeroElectric-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum