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danb

Joined: 29 Sep 2010
Posts: 7

Posted: Thu Sep 30, 2010 2:16 am Post subject: AMPS?

Hello, I am currently wiring my 912uls which has the heavy duty starter. I was not sure how many amps it drew and have had trouble finding this info (I'm sure it's nesteled somewhere in the Rotax pages). 



The question: How many amps will it draw and what size wire should be run to the starter? My Kitfox came with #6AWG, however it was written prior to the heavy duty starter development. Has the amp draw changed?

Thanks,

Dan B

Mesa, AZ

Kitfox IV

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Thu Sep 30, 2010 6:20 pm Post subject: AMPS?

It depends on how far the run will be from your battery to the starter

itself.  The longer the run the bigger the wire you will be needing.  While

you are at it make sure the grounds coming back to the battery from the

engine are hefty too.  



Let us know how long your run will be and then we can make an estimation on

the gauge of wire to use.  I say we because I'm sure this is the kind of

question that will get lots of replies.



Noel



--

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

dan(at)azshowersolutions.
Guest

Posted: Fri Oct 01, 2010 3:17 am Post subject: AMPS?

Noel,

Thanks for the reply. The positive run between my battery and main contactor 

is 6". From there I go to a starter contactor which is about 6" more...then I go 

through the firewall to the starter which will be no more than 15" away. So 

total distance from Batt to starter let's say 30" for a round number. I have a 

copper grounding bus that operates back to back on the firewall. I'm using a #2 

stranded grounding strap to the engine. I realize the bigger the conductor used 

the better, but if I can use the # 6 wire behind the firewall without buying 

more wire, terminals, etc...that would be good.



Thanks for your help

Dan

---

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Fri Oct 01, 2010 7:35 am Post subject: AMPS?

Initially, a starter can draw as much as 80A to 100A or even more. I think

the 6ga wire is a bit thin for this I think I'd go with the 2ga wire from

the battery to the starter.  Two reasons... 1. 2 ga wire will be able to

carry the current with ability to spare (around 150A intermittent).  And 2.

The extra weight of 30" of wire is hardly significant to the plane as a

whole.



One thing bothers me though...  You said your wiring goes about 6" to the

main contactor then another 6" to the starter contactor.  Thatg leads me to

believe that you are drawing all the current for the starter motor through

your main contactor.  That is a lot of current for a continuous contactor to

handle.  I would wire the starter solenoid directly from the battery

parallel with the buss wire and your main contactor.  Then feed the

energizing coil on your starter solenoid with power fed from the main

contactor.  That way there will be less heavy wire energized in flight and

the starter cannot be engaged when the master switch is off.



This has come up before and I have a simplified diagram here I can send

direct if you want it.  



Noel



--

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

rparigoris

Joined: 24 Nov 2009
Posts: 791

Posted: Fri Oct 01, 2010 11:38 am Post subject: Re: AMPS?

Hi Dan B.



The old style starter draws .6kW.



According to Lockwood, the new style starter draws less amps.



For a quick estimate using 60 amps for old style and 50 amps for new style will get you very close to what is probably real draw. Remember this engine is not too much over 70 cubic inches, not 200, 320, 360 or larger.



This info I gathered was based on a 914, but would imagine the 912S would be very similar.



You can choose a larger resolution and look at starter on the right side:

http://www.europaowners.org/forums/gallery2.php?g2_itemId=80372&g2_imageViewsIndex=1



Note if you run starter for 10 seconds, you should wait 2 minutes for cool down.



I have a Odyssey PC525 mounted aft in fuse and am using #4 CCA. Others using #4 have good success, but #2 wire would be a little better.



I think in your instance if #6 worked before, it will work better with the HD starter.



The wire I am using is copper clad aluminium. The diameter is larger than #4 copper but the resistance is just about the same. I almost took the yellow covering off the wire and stripped out strands to make it #5 to save a little weight, then heat shrink Teflon heat shrink over the strands. Sounded good, would have saved a little weight, then I realized just how much weight it was going to save from my rear pocket and idea was put in the bin.



Ron Parigoris

flyadive(at)gmail.com
Guest

Posted: Fri Oct 01, 2010 2:01 pm Post subject: AMPS?

Ron & Dan:



Here is the math for the information you gave:

0.6KW = 600 WATTS

600 WATTS (at) 12 VDC (I use 12 V because you are pulling the power from the Battery)

I (current) = 600 W / 12 VDC = 50 AMPS  But at WHAT TEMP?

 Lets also use 8 VDC... Why?  Because many starters will turn over at a much lower voltage than 12 VDC to insure starting when the battery is low and the temp too.  SOoooo...

I = 600 WATTS / 8 VDC = 75 AMPS  But again at WHAT TEMP?

 



I have VERY STRONG reservations to where and how they came up with this 0.6KW.

It sounds way - way too low.  

I'm betting that current (0.6KW) is a sustained current AFTER the initial surge.

 I doubt if they used a current probe connected to a digital O-Scope to capture the true current draw.  Having done amperage checks on small lawnmowers, they were pulling 100 Amps on a SUMMER DAY.

Don't go borderline.

 



Barry

On Fri, Oct 1, 2010 at 3:38 PM, rparigoris <rparigor(at)suffolk.lib.ny.us (rparigor(at)suffolk.lib.ny.us)> wrote:

  	  Quote: 	
		  --> RotaxEngines-List message posted by: "rparigoris" <rparigor(at)suffolk.lib.ny.us (rparigor(at)suffolk.lib.ny.us)>

  

 Hi Dan B.

 

 The old style starter draws .6kW.

 

 According to Lockwood, the new style starter draws less amps.

 

 For a quick estimate using 60 amps for old style and 50 amps for new style will get you very close to what is probably real draw. Remember this engine is not too much over 70 cubic inches, not 200, 320, 360 or larger.

  

 This info I gathered was based on a 914, but would imagine the 912S would be very similar.

 

 You can choose a larger resolution and look at starter on the right side:

 http://www.europaowners.org/forums/gallery2.php?g2_itemId=80372&g2_imageViewsIndex=1

 

 Note if you run starter for 10 seconds, you should wait 2 minutes for cool down.

 

 I have a Odyssey PC525 mounted aft in fuse and am using #4 CCA. Others using #4 have good success, but #2 wire would be a little better.

 

 I think in your instance if #6 worked before, it will work better with the HD starter.

 

 The wire I am using is copper clad aluminium. The diameter is larger than #4 copper but the resistance is just about the same. I almost took the yellow covering off the wire and stripped out strands to make it #5 to save a little weight, then heat shrink Teflon heat shrink over the strands. Sounded good, would have saved a little weight, then I realized just how much weight it was going to save from my rear pocket and idea was put in the bin.

  

 Ron Parigoris

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=314349#314349

 

 

 

 

 

 

 

 ===========

 -List" target="_blank">http://www.matronics.com/Navigator?RotaxEngines-List

 ===========

 http://forums.matronics.com

 ===========

 le, List Admin.

 ="_blank">http://www.matronics.com/contribution

 ===========

 

 

 

 	


-- 

Barry

 "Chop'd Liver"



 

  [quote][b]

rparigoris

Joined: 24 Nov 2009
Posts: 791

Posted: Fri Oct 01, 2010 2:28 pm Post subject: Re: AMPS?

Hi Barry



I took the 600 watt number somewhere out of Rotax manual.



Being an electric model aeroplane flier, published numbers frequent lie. Almost always they are low because of voltage drops. 



It's true that to achieve the same watt output with a lower voltage you need to up the amperage, in reality when you lower the voltage going to an electric motor the amp draw drops. 



I also don't know for certain if toe 600 watt number is actual amp draw or the output of motor. If it is the output of the motor then you have to add in some amp draw because the motor is not 100% efficient. 



I forget who, but someone at Lockwood gave me their opinion that the 60 amp and 50 amp actual draw was probably close.



Anybody have a clamp on amp meter and can measure a 91X cranking amp draw?



Bottom line is you need enough RPM to allow easy starting when it's cold out. Who cares if the wire gets a little warm. If you can't get enough RPM, then see if you can figure out how to get it up. 



AGM batteries have slightly higher voltage than flooded lead acid, but more important often have a higher cranking voltage. I went for light and the PC545 aft mounted with #4 wires has worked well with folks with the old style starters. A PC680 with #2 wire and forward mounted will spin the engine a little quicker, but who cares if both start easily in the cold. I for one like the net lighter setup with the aft mounted battery because it is lighter and gives me a CG closer to aft than being nose heavy.



Ron Parigoris

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Fri Oct 01, 2010 3:45 pm Post subject: AMPS?

Barry:  

   

If I read you right you like myself feel the 6Ga. feed wire is a bit on the light side.  I agree if someone was to try to push 100 A through that wire it wouldn’t be long before it would heat up and cause even greater resistance.  

   

What would you think an acceptable gauge for the starter feed wire to be?  2Ga. ground straps were mentioned.  

   

I’m almost ready to install the battery in my 912 mod.  I think I’ll have to put the battery behind the seats and that means around an 8’ run.  I’m seriously considering 0Ga or 00Ga. wire.  If I weren’t on floats I’d install a ground power connector.  

   

Noel  

     

From: owner-rotaxengines-list-server(at)matronics.com [mailto:owner-rotaxengines-list-server(at)matronics.com] On Behalf Of FLYaDIVE

 Sent: October 1, 2010 7:28 PM

 To: rotaxengines-list(at)matronics.com

 Subject: Re: Re: AMPS?  

  

   

Ron & Dan:    

   

    

Here is the math for the information you gave:  

    

0.6KW = 600 WATTS  

    

600 WATTS (at) 12 VDC (I use 12 V because you are pulling the power from the Battery)  

    

I (current) = 600 W / 12 VDC = 50 AMPS  But at WHAT TEMP?  

    

Lets also use 8 VDC... Why?  Because many starters will turn over at a much lower voltage than 12 VDC to insure starting when the battery is low and the temp too.  SOoooo...  

    

I = 600 WATTS / 8 VDC = 75 AMPS  But again at WHAT TEMP?  

    

   

    

I have VERY STRONG reservations to where and how they came up with this 0.6KW.  

    

It sounds way - way too low.    

    

I'm betting that current (0.6KW) is a sustained current AFTER the initial surge.  

    

I doubt if they used a current probe connected to a digital O-Scope to capture the true current draw.  Having done amperage checks on small lawnmowers, they were pulling 100 Amps on a SUMMER DAY.  

    

Don't go borderline.  

    

   

    

Barry  

    

   

    

   

    

   

    

     

On Fri, Oct 1, 2010 at 3:38 PM, rparigoris <rparigor(at)suffolk.lib.ny.us (rparigor(at)suffolk.lib.ny.us)> wrote:  

--> RotaxEngines-List message posted by: "rparigoris" <rparigor(at)suffolk.lib.ny.us (rparigor(at)suffolk.lib.ny.us)>

 

 Hi Dan B.

 

 The old style starter draws .6kW.

 

 According to Lockwood, the new style starter draws less amps.

 

 For a quick estimate using 60 amps for old style and 50 amps for new style will get you very close to what is probably real draw. Remember this engine is not too much over 70 cubic inches, not 200, 320, 360 or larger.

 

 This info I gathered was based on a 914, but would imagine the 912S would be very similar.

 

 You can choose a larger resolution and look at starter on the right side:

 http://www.europaowners.org/forums/gallery2.php?g2_itemId=80372&g2_imageViewsIndex=1

 

 Note if you run starter for 10 seconds, you should wait 2 minutes for cool down.

 

 I have a Odyssey PC525 mounted aft in fuse and am using #4 CCA. Others using #4 have good success, but #2 wire would be a little better.

 

 I think in your instance if #6 worked before, it will work better with the HD starter.

 

 The wire I am using is copper clad aluminium. The diameter is larger than #4 copper but the resistance is just about the same. I almost took the yellow covering off the wire and stripped out strands to make it #5 to save a little weight, then heat shrink Teflon heat shrink over the strands. Sounded good, would have saved a little weight, then I realized just how much weight it was going to save from my rear pocket and idea was put in the bin.

 

 Ron Parigoris

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=314349#314349

 

 

 

 

 

 

 

 ===========

 -List" target="_blank">http://www.matronics.com/Navigator?RotaxEngines-List

 ===========

 http://forums.matronics.com

 ===========

 le, List Admin.

 ="_blank">http://www.matronics.com/contribution

 ===========

 

 

   

  



  

 --     

Barry  

    

"Chop'd Liver"  

  

   

   	  Quote: 	
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_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Fri Oct 01, 2010 7:43 pm Post subject: Re: AMPS?

up to 70 amps. If you pull more look for a problem. Use 4ga. wire  even a 2ga. for a long run. The shorter the battery to starter wire the better. Make sure the ground wire is a larger size too.

_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

ptag.dev(at)tiscali.co.uk
Guest

Posted: Sat Oct 02, 2010 12:50 am Post subject: AMPS?

Hi! all.

.......and for my contribution ...use multicore welding wire! On short runs

the weight factor is negligible. Been there got the "T" shirt.

Regards

Bob Harrison Europa G-PTAG 914 Rotax c/w Up graded Starter and never a

problem even with 9 year old Oddessey Batteries.



--

grahamsingleton(at)btinte
Guest

Posted: Sat Oct 02, 2010 12:50 am Post subject: AMPS?

I agree. The impedance of the motor is very low until it starts to turn at a reasonable speed. If it stalls, which it might on a cold day, it will take a lot more current, start to heat up connections and resistance will increase, reducing current still further.

I went for Perihelions Fatwire, copper coated aluminum. Worth reading what he says about it. I used #2 for my Lycoming, #4 should be fine for a Rotax.  <http://www.periheliondesign.com/fatwires.htm>

Graham

From: FLYaDIVE <flyadive(at)gmail.com>

To: rotaxengines-list(at)matronics.com

Sent: Friday, 1 October, 2010 22:57:52

Subject: Re: Re: AMPS?

Ron & Dan:

I have VERY STRONG reservations to where and how they came up with this 0.6KW.

It sounds way - way too low.  

Barry

On Fri, Oct 1, 2010 at 3:38 PM, rparigoris <rparigor(at)suffolk.lib.ny.us (rparigor(at)suffolk.lib.ny.us)> wrote:

  	  Quote: 	
		  --> RotaxEngines-List message posted by: "rparigoris" <rparigor(at)suffolk.lib.ny.us (rparigor(at)suffolk.lib.ny.us)>

 Hi Dan B.

 The old style starter draws .6kW.

 According to Lockwood, the new style starter draws less amps.

 For a quick estimate using 60 amps for old style and 50 amps for new style will get you very close to what is probably real draw. Remember this engine is not too much over 70 cubic inches, not 200, 320, 360 or larger.

 This info I gathered was based on a 914, but would imagine the 912S would be very similar.

 You can choose a larger resolution and look at starter on the right side:

 http://www.europaowners.org/forums/gallery2.php?g2_itemId=80372&g2_imageViewsIndex=1

 Note if you run starter for 10 seconds, you should wait 2 minutes for cool down.

 I have a Odyssey PC525 mounted aft in fuse and am using #4 CCA. Others using #4 have good success, but #2 wire would be a little better.

 I think in your instance if #6 worked before, it will work better with the HD starter.

 The wire I am using is copper clad aluminium. The diameter is larger than #4 copper but the resistance is just about the same. I almost took the yellow covering off the wire and stripped out strands to make it #5 to save a little weight, then heat shrink Teflon heat shrink over the strands. Sounded good, would have saved a little weight, then I realized just how much weight it was going to save from my rear pocket and idea was put in the bin.

 Ron Parigoris

 Read this topic online here:

 http://forums.matronics.com/viewtopic.php?p=314349#314349

 ===========

 -List" target="_blank">http://www.matronics.com/Navigator?RotaxEngines-List

 ===========

 http://forums.matronics.com

 ===========

 le, List Admin.

 ="_blank">http://www.matronics.com/contribution

 ===========

-- 

Barry

 "Chop'd Liver"

  [quote]http://www.matronics.com/Navi========================

" target="_blank" href="http://forums.matronics.com">http://forums.matr   --> [b]

grahamsingleton(at)btinte
Guest

Posted: Sat Oct 02, 2010 1:59 am Post subject: AMPS?

Bob

True! 

Graham

From: Robert C Harrison <ptag.dev(at)tiscali.co.uk>

To: rotaxengines-list(at)matronics.com

Sent: Saturday, 2 October, 2010 9:47:33

Subject: RE: Re: AMPS?

--> RotaxEngines-List message posted by: "Robert C Harrison" <ptag.dev(at)tiscali.co.uk (ptag.dev(at)tiscali.co.uk)>

Hi!  all.

........and for my contribution ...use multicore welding wire! On short runs

the weight factor is negligible. Been there got the "T" shirt.

Regards

Bob Harrison Europa G-PTAG 914 Rotax c/w Up graded Starter and never a

problem even with 9 year old Oddessey Batteries.

  [quote][b]

dan(at)azshowersolutions.
Guest

Posted: Sat Oct 02, 2010 4:52 am Post subject: AMPS?

Gentlemen, I thank you for your replies and attention to this. I put the queston out here as I was getting many  varried answers from other builders as well as Rotax dealers. Lockwood even told me I would be ok with using #6, however, after these informative posts I'm going with a safety margin and ordering #2 cable. 

 Thanks again,

 Dan B

 Mesa, AZ



 

   From: GRAHAM SINGLETON <grahamsingleton(at)btinternet.com>

To: rotaxengines-list(at)matronics.com

Sent: Sat, October 2, 2010 2:56:19 AM

Subject: Re: Re: AMPS?



  Bob

True! 

Graham



 

   From: Robert C Harrison <ptag.dev(at)tiscali.co.uk>

To: rotaxengines-list(at)matronics.com

Sent: Saturday, 2 October, 2010 9:47:33

Subject: RE: Re: AMPS?



--> RotaxEngines-List message posted by: "Robert C Harrison" <ptag.dev(at)tiscali.co.uk (ptag.dev(at)tiscali.co.uk)>



Hi! all.

.......and for my contribution ...use multicore welding wire! On short runs

the weight factor is negligible. Been there got the "T" shirt.

Regards

Bob Harrison Europa G-PTAG 914 Rotax c/w Up graded Starter and never a

problem even with 9 year old Oddessey Batteries.



[quote][b][b]

grahamsingleton(at)btinte
Guest

Posted: Sat Oct 02, 2010 9:54 am Post subject: AMPS?

Dan

you'll be OK with #4

Graham



From: Dan Billingsley <dan(at)azshowersolutions.com>

To: rotaxengines-list(at)matronics.com

Sent: Saturday, 2 October, 2010 13:49:20

Subject: Re: Re: AMPS?



Gentlemen, I thank you for your replies and attention to this. I put the  queston out here as I was getting many  varried answers from other builders as well as Rotax dealers. Lockwood even told me I would be ok with using #6, however, after these informative posts I'm going with a safety margin and ordering #2 cable. 

 Thanks again,

 Dan B

 Mesa, AZ



 

   From: GRAHAM SINGLETON <grahamsingleton(at)btinternet.com>

To: rotaxengines-list(at)matronics.com

Sent: Sat, October 2, 2010 2:56:19 AM

Subject: Re: Re: AMPS?



  Bob

True! 

Graham



 

   From: Robert C Harrison <ptag.dev(at)tiscali.co.uk>

To: rotaxengines-list(at)matronics.com

Sent: Saturday, 2 October, 2010 9:47:33

Subject: RE: Re: AMPS?



--> RotaxEngines-List message posted by: "Robert C Harrison" <ptag.dev(at)tiscali.co.uk (ptag.dev(at)tiscali.co.uk)>



Hi! all.

........and for my contribution ...use multicore welding wire! On short runs

the weight factor is negligible. Been there got the "T" shirt.

Regards

Bob Harrison Europa G-PTAG 914 Rotax c/w Up graded Starter and never a

problem even with 9 year old Oddessey Batteries.



 	  Quote: 	
		  http://www.matronics.cfollow" target="_blank" href="http://forums.matronics.com">http://forum==========

flyadive(at)gmail.com
Guest

Posted: Sun Oct 03, 2010 8:44 am Post subject: AMPS?

 	  Quote: 	
		  Ron:

	




You are going to have to explain your statement on this on:

 "  in reality when you lower the voltage going to an electric motor the amp draw drops."

When you lower the voltage AND the motor still runs the AMPERAGE MUST GO UP.

I = E/R

 The FIXED is the Resistance.  The only variance in the Resistance is due to Heat and Brush Ware.

At some point in dropping the voltage the motor will not function  - That is because the voltage is too low to produce an inductive field in the stator and rotor..  

 BUT!  As long as the voltage is enough to make the motor move the Current  ( I ) will go UP.

There is NO OTHER - REALITY - Statement.

I know, I know I'm a PITA and a stickler to detail.

  	  Quote: 	
		  

"I also don't know for certain if toe 600 watt number is actual amp draw or the output of motor. If it is the output of the motor then you have to add in some amp draw because the motor is not 100% efficient."

 	




There are two  (2) things not known:

1 - When and How the readings were taken to determine the 0.6KW... As I stated in my previous post.  I betting they were taken AFTER the starter motor reached  full speed.

 



2 - You statement of "100% efficient" does not have ANYTHING to do with this.  Efficiency is equal to OUTPUT divided my INPUT.  % - IN / OUT.  And we don't care what the OUT is.  We are only interested in what the IN is... HOW MUCH INPUT CURRENT will the Starter Motor draw during startup.

 



AND - It is the instantaneous Current with the high mechanical load that the Wires must handle.

AHhhh clamp on meters... That is what I'm betting the the manufacture used to get the current draw.

 They show ONLY an RMS value and not the peak.  Guess-factoring you can add 29.3% <<<--- a real number, more to that reading to be more in-line with what the wire should be handling.  And "should be handling'", my quote, does not give a safety margin. A step up of at least one wire size would be minimum.

 



Again I must state: I know, I know I'm a PITA and a stickler to detail.

Barry



  [quote][b]

grahamsingleton(at)btinte
Guest

Posted: Sun Oct 03, 2010 9:07 am Post subject: AMPS?

No. The faster the motor runs the greater the back EMF. So the lower the current.

Graham

From: FLYaDIVE <flyadive(at)gmail.com>

To: rotaxengines-list(at)matronics.com

Sent: Sunday, 3 October, 2010 17:42:01

Subject: Re: RotaxEngines-List: Re: AMPS?

 	  Quote: 	
		  Ron:

You are going to have to explain your statement on this on:

 "  in reality when you lower the voltage going to an electric motor the amp draw drops."

When you lower the voltage AND the motor still runs the AMPERAGE MUST GO UP.

I = E/R

 The FIXED is the Resistance.  The only variance in the Resistance is due to Heat and Brush Ware.

At some point in dropping the voltage the motor will not function  - That is because the voltage is too low to produce an inductive field in the stator and rotor..  

 BUT!  As long as the voltage is enough to make the motor move the Current  ( I ) will go UP.

  [quote][b]

flyadive(at)gmail.com
Guest

Posted: Sun Oct 03, 2010 9:29 am Post subject: AMPS?

Hello Noel:



I really like your idea of a Ground Power Connector, they offer all sorts of advantages.

 How does being on floats negate the Ground Power Connector?

As you know and mentioned, wire run length is a major factor.  An AWG of 2 should do well for short runs of wire and that #2 does have a safety margin figured in.  Going to an AWG of 0 for BOTH POSITIVE & NEGATIVE runs should work VERY well.

 I have never use it - But, there have been many reports of using 'welder's cable', very flexible, abrasion resistance, low resistance and available at welding supply houses.  They also have the ring lugs.

 



AND - Gaggle - I know I posted this before but it REALLY is a GREAT TRICK:

 SOLDER the wire to the ring lug ONLY at the end next to the mounting part of the ring lug.

Crimp First - Then older.  Clean well.

 



Barry



 

  



On Fri, Oct 1, 2010 at 7:40 PM, Noel Loveys <noelloveys(at)yahoo.ca (noelloveys(at)yahoo.ca)> wrote:

  	  Quote: 	
		               

Barry:  

   

If I read you right you like myself feel the 6Ga. feed wire is a bit on the light side.  I agree if someone was to try to push 100 A through that wire it wouldn’t be long before it would heat up and cause even greater resistance.  

   

What would you think an acceptable gauge for the starter feed wire to be?  2Ga. ground straps were mentioned.  

   

I’m almost ready to install the battery in my 912 mod.  I think I’ll have to put the battery behind the seats and that means around an 8’ run.  I’m seriously considering 0Ga or 00Ga. wire.  If I weren’t on floats I’d install a ground power connector.  

   

Noel  

     

From: owner-rotaxengines-list-server(at)matronics.com (owner-rotaxengines-list-server(at)matronics.com) [mailto:owner-rotaxengines-list-server(at)matronics.com (owner-rotaxengines-list-server(at)matronics.com)] On Behalf Of FLYaDIVE

 Sent: October 1, 2010 7:28 PM

 To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)

 Subject: Re: Re: AMPS?  

  

   

Ron & Dan:    

   

    

Here is the math for the information you gave:  

    

0.6KW = 600 WATTS  

    

600 WATTS (at) 12 VDC (I use 12 V because you are pulling the power from the Battery)  

    

I (current) = 600 W / 12 VDC = 50 AMPS  But at WHAT TEMP?  

    

Lets also use 8 VDC... Why?  Because many starters will turn over at a much lower voltage than 12 VDC to insure starting when the battery is low and the temp too.  SOoooo...  

    

I = 600 WATTS / 8 VDC = 75 AMPS  But again at WHAT TEMP?  

    

   

    

I have VERY STRONG reservations to where and how they came up with this 0.6KW.  

    

It sounds way - way too low.    

    

I'm betting that current (0.6KW) is a sustained current AFTER the initial surge.  

    

I doubt if they used a current probe connected to a digital O-Scope to capture the true current draw.  Having done amperage checks on small lawnmowers, they were pulling 100 Amps on a SUMMER DAY.  

    

Don't go borderline.  

    

   

    

Barry  

    

   

    

   

    

   

    

     

On Fri, Oct 1, 2010 at 3:38 PM, rparigoris <rparigor(at)suffolk.lib.ny.us (rparigor(at)suffolk.lib.ny.us)> wrote:  



--> RotaxEngines-List message posted by: "rparigoris" <rparigor(at)suffolk.lib.ny.us (rparigor(at)suffolk.lib.ny.us)>

 



 Hi Dan B.

 

 The old style starter draws .6kW.

 

 According to Lockwood, the new style starter draws less amps.

 

 For a quick estimate using 60 amps for old style and 50 amps for new style will get you very close to what is probably real draw. Remember this engine is not too much over 70 cubic inches, not 200, 320, 360 or larger.

 

 This info I gathered was based on a 914, but would imagine the 912S would be very similar.

 

 You can choose a larger resolution and look at starter on the right side:

 http://www.europaowners.org/forums/gallery2.php?g2_itemId=80372&g2_imageViewsIndex=1

 

 Note if you run starter for 10 seconds, you should wait 2 minutes for cool down.

 

 I have a Odyssey PC525 mounted aft in fuse and am using #4 CCA. Others using #4 have good success, but #2 wire would be a little better.

 

 I think in your instance if #6 worked before, it will work better with the HD starter.

 

 The wire I am using is copper clad aluminium. The diameter is larger than #4 copper but the resistance is just about the same. I almost took the yellow covering off the wire and stripped out strands to make it #5 to save a little weight, then heat shrink Teflon heat shrink over the strands. Sounded good, would have saved a little weight, then I realized just how much weight it was going to save from my rear pocket and idea was put in the bin.

 

 Ron Parigoris

 

 

 

 

 Read this topic online here:

 

 

http://forums.matronics.com/viewtopic.php?p=314349#314349

 

 

 

 

 

 

 

 ===========

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 ===========

 http://forums.matronics.com

 ===========

 le, List Admin.

 ="_blank">http://www.matronics.com/contribution

 ===========

 

 

 

  

  



  

 --     

Barry  

    

"Chop'd Liver"  

  

   

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Barry

 "Chop'd Liver"



 

  [quote][b]

flyadive(at)gmail.com
Guest

Posted: Sun Oct 03, 2010 9:49 am Post subject: AMPS?

Gaggle:

 

 	  Quote: 	
		   WHAT A SCREW UP!

	




I put in the wrong formula.  

I = P / E  

 



Sorry -  Did anyone else catch it?

Barry

 

 	  Quote: 	
		    

 	  Quote: 	
		  Ron:

	




You are going to have to explain your statement on this on:

  "  in reality when you lower the voltage going to an electric motor the amp draw drops."

When you lower the voltage AND the motor still runs the AMPERAGE MUST GO UP.

I = E/R

  The FIXED is the Resistance.  The only variance in the Resistance is due to Heat and Brush Ware.

At some point in dropping the voltage the motor will not function  - That is because the voltage is too low to produce an inductive field in the stator and rotor..  

  BUT!  As long as the voltage is enough to make the motor move the Current  ( I ) will go UP.



 

   	  Quote: 	
		  



ist" target="_blank">http://www.matronics.com/Navigator?RotaxEngines-List

tp://forums.matronics.com

_blank">http://www.matronics.com/contribution



	




	


-- 

Barry

 "Chop'd Liver"



  [quote][b]

rparigoris

Joined: 24 Nov 2009
Posts: 791

Posted: Sun Oct 03, 2010 1:00 pm Post subject: Re: AMPS?

Hi Barry



"It's true that to achieve the same watt output with a lower voltage you need to up the amperage, in reality when you lower the voltage going to an electric motor the amp draw drops."



If you have a battery or power supply with wires that can keep the lowering of voltage and amperage to a minimum, then it's true that if you lower the voltage to a motor that is reasonably loaded the amp draw will go up since the motor can't spin as fast as if it had higher voltage (within reason as far as voltage and load and motor timing).



What I was getting at is that often (VERY OFTEN with high performance moder electrics) you may have a battery and wire size that is very close to asking max. amps that the battery can offer while maintaining a reasonable voltage.

If you ask any more amps it will begin to give up a lot of voltage and not offer up any more amps. If you have long thin wires that only drop voltage further, then heat the wires up and drop voltage even further, often you are asking more amps from the battery that it can put out. The scenario is the battery is huffing and puffing harder and harder but begins dropping amp output and voltage, and the wires are warming up and making things worst. Net is if you see too little voltage at a running loaded motor (again within reason and you calculated what you are looking for), it probably means you have a battery that has not enough ability to dump amps and keep the voltage up, and or the wires are creating too much resistance and dropping voltage. In this scenario of marginal battery and wires, lets put it in the cold where the battery is offering up even less performance and the motor is offering up more resistance to turning and we measure a lower voltage going to the motor, the motor will just plain not be seeing very many amps going to it compared to a warm battery and engine.



Again what really matters to me is when it's cold out I can start my bird. 



BTW on cars it works where on a cold day if you turn on all loads for a few minutes before starting the the warming up of the battery compared to the watts used  nets to more cranking power.



Also with electric motors timing is every bit as important as on IC motors. You want to select proper advance for what you are doing. You never want to run a brushed motor retarded from neutral. Amp draw will go way up and brush life and power output way down. Select too much advance for a highly loaded motor and if you can provide enough amps you will get a little more power output, but often the battery/wires net to less power and you are better off running closer to a neutral timing. I wouldn't be too surprised if someone tried a few motors and optimized timing for our 91Xs to get the high output version that draws less amps than the original. I wouldn't be too surprised if the original motor wouldn't benefit a lot by optimized timing, but then again it may not be too easy to adjust.

Ron Parigoris

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Mon Oct 04, 2010 4:36 pm Post subject: AMPS?

Barry:  

   

There are a few reasons why I wouldn’t use a ground power connector.  First is there are no brakes on a float plane.  It would work great if I had someone else to remove the connector after starting the engine.  Tying the tail is with a slip knot is an option but then I would still have to have the engine running with no one in the cockpit...  not the best idea.  Finally is of course the possibility of damaging the ground battery pack if the connector happened to fall in the drink.  

   

Wheel planes are another quintal of fish!  There are chocks to hold them in place and usually a few people to remove the connector and of course it gives you plenty of power for those cold morning starts without having to worry about carrying the batteries aloft.  

   

Noel  

     

From: owner-rotaxengines-list-server(at)matronics.com [mailto:owner-rotaxengines-list-server(at)matronics.com] On Behalf Of FLYaDIVE

 Sent: October 3, 2010 2:56 PM

 To: rotaxengines-list(at)matronics.com

 Subject: Re: Re: AMPS?  

  

   

Hello Noel:    

   

    

I really like your idea of a Ground Power Connector, they offer all sorts of advantages.  

    

How does being on floats negate the Ground Power Connector?  

    

   

    

As you know and mentioned, wire run length is a major factor.  An AWG of 2 should do well for short runs of wire and that #2 does have a safety margin figured in.  Going to an AWG of 0 for BOTH POSITIVE & NEGATIVE runs should work VERY well.  

    

I have never use it - But, there have been many reports of using 'welder's cable', very flexible, abrasion resistance, low resistance and available at welding supply houses.  They also have the ring lugs.  

    

   

    

AND - Gaggle - I know I posted this before but it REALLY is a GREAT TRICK:  

    

SOLDER the wire to the ring lug ONLY at the end next to the mounting part of the ring lug.  

    

Crimp First - Then older.  Clean well.  

    

   

    

Barry  

    

   

    

   

    

      

On Fri, Oct 1, 2010 at 7:40 PM, Noel Loveys <noelloveys(at)yahoo.ca (noelloveys(at)yahoo.ca)> wrote:      

Barry:  

   

If I read you right you like myself feel the 6Ga. feed wire is a bit on the light side.  I agree if someone was to try to push 100 A through that wire it wouldn’t be long before it would heat up and cause even greater resistance.  

   

What would you think an acceptable gauge for the starter feed wire to be?  2Ga. ground straps were mentioned.  

   

I’m almost ready to install the battery in my 912 mod.  I think I’ll have to put the battery behind the seats and that means around an 8’ run.  I’m seriously considering 0Ga or 00Ga. wire.  If I weren’t on floats I’d install a ground power connector.  

   

Noel  

     

From: owner-rotaxengines-list-server(at)matronics.com (owner-rotaxengines-list-server(at)matronics.com) [mailto:owner-rotaxengines-list-server(at)matronics.com (owner-rotaxengines-list-server(at)matronics.com)] On Behalf Of FLYaDIVE

 Sent: October 1, 2010 7:28 PM

 To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)

 Subject: Re: Re: AMPS?  

  

   

Ron & Dan:    

   

    

Here is the math for the information you gave:  

    

0.6KW = 600 WATTS  

    

600 WATTS (at) 12 VDC (I use 12 V because you are pulling the power from the Battery)  

    

I (current) = 600 W / 12 VDC = 50 AMPS  But at WHAT TEMP?  

    

Lets also use 8 VDC... Why?  Because many starters will turn over at a much lower voltage than 12 VDC to insure starting when the battery is low and the temp too.  SOoooo...  

    

I = 600 WATTS / 8 VDC = 75 AMPS  But again at WHAT TEMP?  

    

   

    

I have VERY STRONG reservations to where and how they came up with this 0.6KW.  

    

It sounds way - way too low.    

    

I'm betting that current (0.6KW) is a sustained current AFTER the initial surge.  

    

I doubt if they used a current probe connected to a digital O-Scope to capture the true current draw.  Having done amperage checks on small lawnmowers, they were pulling 100 Amps on a SUMMER DAY.  

    

Don't go borderline.  

    

   

    

Barry  

    

   

    

   

    

   

    

       

On Fri, Oct 1, 2010 at 3:38 PM, rparigoris <rparigor(at)suffolk.lib.ny.us (rparigor(at)suffolk.lib.ny.us)> wrote:  

    

--> RotaxEngines-List message posted by: "rparigoris" <rparigor(at)suffolk.lib.ny.us (rparigor(at)suffolk.lib.ny.us)>  

  

Hi Dan B.

 

 The old style starter draws .6kW.

 

 According to Lockwood, the new style starter draws less amps.

 

 For a quick estimate using 60 amps for old style and 50 amps for new style will get you very close to what is probably real draw. Remember this engine is not too much over 70 cubic inches, not 200, 320, 360 or larger.

 

 This info I gathered was based on a 914, but would imagine the 912S would be very similar.

 

 You can choose a larger resolution and look at starter on the right side:

 http://www.europaowners.org/forums/gallery2.php?g2_itemId=80372&g2_imageViewsIndex=1

 

 Note if you run starter for 10 seconds, you should wait 2 minutes for cool down.

 

 I have a Odyssey PC525 mounted aft in fuse and am using #4 CCA. Others using #4 have good success, but #2 wire would be a little better.

 

 I think in your instance if #6 worked before, it will work better with the HD starter.

 

 The wire I am using is copper clad aluminium. The diameter is larger than #4 copper but the resistance is just about the same. I almost took the yellow covering off the wire and stripped out strands to make it #5 to save a little weight, then heat shrink Teflon heat shrink over the strands. Sounded good, would have saved a little weight, then I realized just how much weight it was going to save from my rear pocket and idea was put in the bin.    



 

 Ron Parigoris

 

 

 

 

 Read this topic online here:  

  

http://forums.matronics.com/viewtopic.php?p=314349#314349

 

 

 

 

 

 

 

 ===========

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 ===========

 http://forums.matronics.com

 ===========

 le, List Admin.

 ="_blank">http://www.matronics.com/contribution

 ===========

 

   

  



  

 --     

Barry  

    

"Chop'd Liver"  

  

   

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 --     

Barry  

    

"Chop'd Liver"  

  

   

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_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

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