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Float Flyr
Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland
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 Posted: Mon Oct 04, 2010 6:09 pm Post subject: AMPS? |
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I'm not trying to be cute here but I do have to ask what are high
performance moder electrics? Do you mean modular or motor?
I'm interested in your idea of running all loads for a few minutes before
trying to start a cold car. Problem with that as I see it and believe me
this far north I do see quite a bit of cold, is the battery itself doesn't
warm up in discharge but actually polarizes faster. (grows bubbles of
hydrogen on the plates lowering power.) In fact in really cold weather the
oil itself may thicken enough that you will have to make two tries a couple
of minutes apart just to get the crank to spin. Don't ask what current or
voltage drop the starter would demand on one of those occasions. Needless
to say starting any engine not pre heated is just another game of roulette.
BTW Changing gears on a really cold (older type) transmission also can be
lots of fun! The clutch will feel like a rock and you may need both hands
to get it in gear. You get used to driving the first twenty minutes in
first until things start to warm up a bit. I've also been cars where the
brake fluid got cold enough that stopping was interesting.. Sometimes I'd
have to waid five minutes for the brakes to release... thank god for disk
brakes!
My understanding of electric motors is they are dumber than Homer Simpson.
When designed to operate with a specific current, voltage and load they are
more than happy to do so. But if you increase the load they will literally
commit Hari Kari by drawing more and more current until they overheat and
burn out in an attempt to handle a too large load. My instruction was to
make sure the feed to the motor was sufficient to provide enough current
with a minimum of voltage drop for a design load. Basically that means that
you can't use too large feed wires. Planes unlike ships, boats, cars and
trucks have to be light enough to fly so weight and balance become paramount
in importance otherwise we would all be using 0000Ga cable and this thread
wouldn't be here. If I were to err on choosing a cable to handle a starter
motor I'd choose to have one size larger cable than what I think is actually
needed. That way my current resistance and voltage drop across the cable is
minimized for times when my battery may be a little weak or the oil may be a
little cool.
Noel
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Noel Loveys
Kitfox III-A
Aerocet 1100 Floats |
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rparigoris
Joined: 24 Nov 2009
Posts: 797
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| Posted: Tue Oct 05, 2010 12:49 am Post subject: Re: AMPS? |
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Hi Noel
"I'm not trying to be cute here but I do have to ask what are high
performance moder electrics? Do you mean modular or motor?"
I'm trying to be cute here, I was referring to a "modular" motor propulsion units!
Serious, I committed a typo, it was supposed to be "model" electrics.
I designed what I call "Quick Sticks". I love flying wings, and can change out modular propulsion units in seconds. I can go from a lightweight slope soarer, to a mild powered flying machine with great duration to a downright "beast", direct drive for speed and redrive for climb and efficiency.
I garbage pick CF arrows form the local sporting goods store that hit the cinder block wall, wrap them with Spectra and thin CA the Spectra in place and mount batteries, ESC (Electronic speed controller) with various configurations of motors, transmissions and props. Many tweaked to a very nice mix of light yet quite effective.
Here in the middle of page on red hood of car is some of my earlier examples:
http://www.europaowners.org/forums/gallery2.php?g2_itemId=28737
I have many an hour tweaking, measuring and tweaking some more.
The initial flying wing was a Zagi THL. It was designed to come in at 10 oz. I of course had to make a nice light one to slope in very calm conditions that came in under 8 oz! Quick Sticks installed can give me an all up weight of about 18 oz to 3+1/2 pounds.
Now to explore the other end, I took a bungee and a number of steel pipes. I kept on increasing weight and launching till I got to 4+1/2 pounds! The wings were flexing a bit too much but the thing flew great! I fabricated a wing that was stronger and added 16 zapped CP1700 cells that were at their absolute limit of dumping amps connected to an Aveox 3/4 horse power motor with 4.4 to 1 planetary reduction drive and 14.5" x 14 hand laid up RF prop. Egads, over 100mph and absolute pure vertical out of sight in seconds. I use a double bungee to launch it. Landing was a bit of a problem where even with 3 degrees washout it would tip stall sometimes and stall spin. No problem, I built another wing with less wing area (still 4 foot span) higher aspect ratio and thinner, and increased weight to 5 pounds! however I installed articulatable NASA lead edge droop where I could select 30 degrees positive and 5 degrees negative. 20 degrees drags things up but turns it into a pussy cat, negative 5 degrees increases speed (probably negates washout) but you do not want to stall it:
See bout 1/2 way down page
http://www.europaowners.org/forums/gallery2.php?g2_itemId=27305&g2_page=1
BTW you can see how I am using my Quick Stick technology as a total loss battery for my Europa with Rotax 914 as an emergency way to run a fuel pump, could probably even start the 914. Even though it is only 2.2 pounds, It will handle a 70 amp discharge once in a while without breaking too much of a sweat, I wouldn't do it as a habit, but if I was trying to make a mid air restart after soaring and either the motor got a little cold or my main battery failed, putting this 15+ volt nominal battery in parallel with my main battery would probably do good things for starting. If I had the altitude and my main battery (or connection) somehow failed, I would probably use my total loss to do an air restart, even though I don't like spinning a cold engine so fast right away:
http://www.europaowners.org/forums/gallery2.php?g2_itemId=27305&g2_page=1
Also coming out of Quick Stick technology is cooling aid for my Rotax 914 install on my Europa XS. I have a folder that will have the ability to run forward with plenty of pitch speed to aid cooling of oil and coolant radiators, but also the ability to run in reverse to help warm up the fluids, in flight start after soaring will sure be a good time, and i am thinking it may even add a little speed in cruise, a pseude cowl flap if you will. I am also installing two speed 400s hidden behind cowl gills. The Europa XS monowheel suffers from overheating on ground and during climb in hot weather. this is my attempt at keeping things cool:
http://www.europaowners.org/forums/gallery2.php?g2_itemId=28737
Here is schematic for cooling fans:
http://www.europaowners.org/forums/gallery2.php?g2_itemId=79814
Using Eric Jones servo controller (knob in panel insert) to control a ESC, and a DPTT switch with a reverse red LED and a blue forward LED:
http://www.europaowners.org/forums/gallery2.php?g2_itemId=81189
BTW I am using an aft mounted Odyssed PC545 battery to crank my Rotax 914 with new style starter, using Eric Jones CCA #4 wire crimped then soldered with 2% silver solder from McMaster Carr with a lower melting point compared to 63-37 or 60-40. Any copper on the airplane gets plated with cool amp (silver plating right in place):
http://www.europaowners.org/forums/gallery2.php?g2_itemId=30710&g2_page=1
Boy talking about blabbing!
Ron Parigoris
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flyadive(at)gmail.com
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| Posted: Tue Oct 05, 2010 4:24 am Post subject: AMPS? |
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Noel:
Good points - I was thinking about some of them as I was writing you. I'm sure there are hundreds of issues I do not know about, not having been in a float plane.
And I guess when the weather gets so cold that you have to worry about an APU for starting - You also have to start worrying about ICE on the lake. 
Barry
On Mon, Oct 4, 2010 at 8:32 PM, Noel Loveys <noelloveys(at)yahoo.ca (noelloveys(at)yahoo.ca)> wrote:
| Quote: |
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 (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 3, 2010 2:56 PM
To: rotaxengines-list(at)matronics.com (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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"Chop'd Liver"
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flyadive(at)gmail.com
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| Posted: Tue Oct 05, 2010 4:41 am Post subject: AMPS? |
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Ron:
I also fly R/C, have been doing it since 1972. And I have yet to see a motor with a variable phase angle where you can change the timing. The brushes must make contact and that's all there is. Anything else is ... Well, it IS ____ ! Let the designers handle that WE do not have any control over it. And personally I prefer Glow & Gas engines. They sound better. THEY SOUND!
As for the "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."
--- Wait a minute ... Let me put my Hip Boots on. Who is feeding you this BS?
When you put a battery under cold condition you are loosing between 15% to 33% of the cranking ability. Hey, don't take my word for it LQQK at your battery and read the CA Vs CCA ratings. NOW, you want some poor person to turn On their lights and etc., to draw from this already weak battery BEFORE you try to start! How many ways is that wrong.
1 - If you want to put a load on the battery what better load then JUST STARTING!
2 - Do you REALLY think a load of 200 to 250 Watts for a "few minutes" is much of a load to heat a battery? ! ? Ha Ha Ha Heat the battery! I would rather have a stray cat curl up with the battery than waste the time and energy trying to heat the battery, by running it down.
3 - Have you worked out how much of a load Lights and a Fan are?
4 - Question: What does a battery store?
5 - How warm do you thing the battery will get? Lets LQQK at the MASS of the battery - - Forget MASS, let's keep it simple, think of weight... How heavy is a battery? And at what temperature is this battery 32F, 20F maybe 10F? And how many calories of heat do you think is required to raise the temperature of this battery by 1 Degree F? Not even 1 Deg C.
6 - Don't forget the LEAD of the battery is a heat sink. And so is the WATER - whoops ELECTROLYTE.
Still want to heat up the battery before starting?
Put a 100 Watt bulb next to it. And leave it on over night. Over Night that is how long it takes on a cold night.
GEEEEEEEE I wonder why car companies haven't told the public about this trick?
Tell your Wife this trick - And when the battery is DEAD - She will go in the house to get warm and YOU can charge the battery. And DON'T yell at her, that she did something wrong - Other wise you may need some place to stay warm. Curl up in the dog house with Fido.
I'm not picking on you Ron, I HATE the internet for what it does in the WRONG way - It propagates Old Wife's Tails and bull at the speed of an electron.
In this case Shoot the Messenger that gave you that story.
Barry
On Sun, Oct 3, 2010 at 5:00 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 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, t!
he 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
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=314525#314525
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Barry
"Chop'd Liver"
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Float Flyr
Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland
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| Posted: Tue Oct 05, 2010 5:12 am Post subject: AMPS? |
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Thanks Ron that was most interesting.
Noel
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Noel Loveys
Kitfox III-A
Aerocet 1100 Floats |
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Float Flyr
Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland
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| Posted: Tue Oct 05, 2010 5:23 am Post subject: AMPS? |
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Ice on the lake does shorten the flying season for me... I do have skiis for the plane but it’s a bother taking the floats off and then ransporting the plane to a location to fly from. For me flying is definitely a warm weather pastime.
Noel
From: owner-rotaxengines-list-server(at)matronics.com [mailto:owner-rotaxengines-list-server(at)matronics.com] On Behalf Of FLYaDIVE
Sent: October 5, 2010 9:45 AM
To: rotaxengines-list(at)matronics.com
Subject: Re: Re: AMPS?
Noel:
Good points - I was thinking about some of them as I was writing you. I'm sure there are hundreds of issues I do not know about, not having been in a float plane.
And I guess when the weather gets so cold that you have to worry about an APU for starting - You also have to start worrying about ICE on the lake.
Barry
On Mon, Oct 4, 2010 at 8:32 PM, Noel Loveys <noelloveys(at)yahoo.ca (noelloveys(at)yahoo.ca)> wrote:
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 (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 3, 2010 2:56 PM
To: rotaxengines-list(at)matronics.com (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
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Float Flyr
Joined: 19 Jul 2006
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Location: Campbellton, Newfoundland
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| Posted: Tue Oct 05, 2010 5:29 am Post subject: AMPS? |
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I think Ron is getting at a different kind of battery. I have noticed with an old electric razor it speeds up a lot after a minute or so of operation. I have no idea why as there is little or no load on the motor when it is first turned on. I would have thought that after a minute or so it would have actually slwed down not speeded up.... go figure.
Noel
From: owner-rotaxengines-list-server(at)matronics.com [mailto:owner-rotaxengines-list-server(at)matronics.com] On Behalf Of FLYaDIVE
Sent: October 5, 2010 10:09 AM
To: rotaxengines-list(at)matronics.com
Subject: Re: Re: AMPS?
Ron:
I also fly R/C, have been doing it since 1972. And I have yet to see a motor with a variable phase angle where you can change the timing. The brushes must make contact and that's all there is. Anything else is ... Well, it IS ____ ! Let the designers handle that WE do not have any control over it. And personally I prefer Glow & Gas engines. They sound better. THEY SOUND!
As for the "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."
--- Wait a minute ... Let me put my Hip Boots on. Who is feeding you this BS?
When you put a battery under cold condition you are loosing between 15% to 33% of the cranking ability. Hey, don't take my word for it LQQK at your battery and read the CA Vs CCA ratings. NOW, you want some poor person to turn On their lights and etc., to draw from this already weak battery BEFORE you try to start! How many ways is that wrong.
1 - If you want to put a load on the battery what better load then JUST STARTING!
2 - Do you REALLY think a load of 200 to 250 Watts for a "few minutes" is much of a load to heat a battery? ! ? Ha Ha Ha Heat the battery! I would rather have a stray cat curl up with the battery than waste the time and energy trying to heat the battery, by running it down.
3 - Have you worked out how much of a load Lights and a Fan are?
4 - Question: What does a battery store?
5 - How warm do you thing the battery will get? Lets LQQK at the MASS of the battery - - Forget MASS, let's keep it simple, think of weight... How heavy is a battery? And at what temperature is this battery 32F, 20F maybe 10F? And how many calories of heat do you think is required to raise the temperature of this battery by 1 Degree F? Not even 1 Deg C.
6 - Don't forget the LEAD of the battery is a heat sink. And so is the WATER - whoops ELECTROLYTE.
Still want to heat up the battery before starting?
Put a 100 Watt bulb next to it. And leave it on over night. Over Night that is how long it takes on a cold night.
GEEEEEEEE I wonder why car companies haven't told the public about this trick?
Tell your Wife this trick - And when the battery is DEAD - She will go in the house to get warm and YOU can charge the battery. And DON'T yell at her, that she did something wrong - Other wise you may need some place to stay warm. Curl up in the dog house with Fido.
I'm not picking on you Ron, I HATE the internet for what it does in the WRONG way - It propagates Old Wife's Tails and bull at the speed of an electron.
In this case Shoot the Messenger that gave you that story.
Barry
On Sun, Oct 3, 2010 at 5:00 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 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, t!
he 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
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=314525#314525
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dan(at)azshowersolutions.
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| Posted: Tue Oct 05, 2010 5:00 pm Post subject: AMPS? |
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This has been a very good discussion. Years ago I attended one of the Nuckolls workshops, so I thought to join that group and ask him to take a looksee at our Amp topic. He did, so for more info and opinion check out Bob's take...
http://tinyurl.com/25t4lh3
You might suggest that those folks also join us on
the AeroElectric-List.
Bob . . .
From: Noel Loveys <noelloveys(at)yahoo.ca>
To: rotaxengines-list(at)matronics.com
Sent: Tue, October 5, 2010 6:27:22 AM
Subject: RE: Re: AMPS?
I think Ron is getting at a different kind of battery. I have noticed with an old electric razor it speeds up a lot after a minute or so of operation. I have no idea why as there is little or no load on the motor when it is first turned on. I would have thought that after a minute or so it would have actually slwed down not speeded up.... go figure.
Noel
From: owner-rotaxengines-list-server(at)matronics.com [mailto:owner-rotaxengines-list-server(at)matronics.com] On Behalf Of FLYaDIVE
Sent: October 5, 2010 10:09 AM
To: rotaxengines-list(at)matronics.com
Subject: Re: Re: AMPS?
Ron:
I also fly R/C, have been doing it since 1972. And I have yet to see a motor with a variable phase angle where you can change the timing. The brushes must make contact and that's all there is. Anything else is ... Well, it IS ____ ! Let the designers handle that WE do not have any control over it. And personally I prefer Glow & Gas engines. They sound better. THEY SOUND!
As for the "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."
--- Wait a minute ... Let me put my Hip Boots on. Who is feeding you this BS?
When you put a battery under cold condition you are loosing between 15% to 33% of the cranking ability. Hey, don't take my word for it LQQK at your battery and read the CA Vs CCA ratings. NOW, you want some poor person to turn On their lights and etc., to draw from this already weak battery BEFORE you try to start! How many ways is that wrong.
1 - If you want to put a load on the battery what better load then JUST STARTING!
2 - Do you REALLY think a load of 200 to 250 Watts for a "few minutes" is much of a load to heat a battery? ! ? Ha Ha Ha Heat the battery! I would rather have a stray cat curl up with the battery than waste the time and energy trying to heat the battery, by running it down.
3 - Have you worked out how much of a load Lights and a Fan are?
4 - Question: What does a battery store?
5 - How warm do you thing the battery will get? Lets LQQK at the MASS of the battery - - Forget MASS, let's keep it simple, think of weight... How heavy is a battery? And at what temperature is this battery 32F, 20F maybe 10F? And how many calories of heat do you think is required to raise the temperature of this battery by 1 Degree F? Not even 1 Deg C.
6 - Don't forget the LEAD of the battery is a heat sink. And so is the WATER - whoops ELECTROLYTE.
Still want to heat up the battery before starting?
Put a 100 Watt bulb next to it. And leave it on over night. Over Night that is how long it takes on a cold night.
GEEEEEEEE I wonder why car companies haven't told the public about this trick?
Tell your Wife this trick - And when the battery is DEAD - She will go in the house to get warm and YOU can charge the battery. And DON'T yell at her, that she did something wrong - Other wise you may need some place to stay warm. Curl up in the dog house with Fido.
I'm not picking on you Ron, I HATE the internet for what it does in the WRONG way - It propagates Old Wife's Tails and bull at the speed of an electron.
In this case Shoot the Messenger that gave you that story.
Barry
On Sun, Oct 3, 2010 at 5:00 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 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, t!
he 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
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=314525#314525
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="_blank">http://www.matronics.com/contribution
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"Chop'd Liver"
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jetboy
Joined: 22 Jul 2006
Posts: 233
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| Posted: Fri Oct 08, 2010 1:01 pm Post subject: Re: AMPS? |
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Minimum steady state cranking amps is 75 for the 912S
This is described in SB-912-042 R1
We did this test on a troublesome 912UL and got 71 amps. Although the SB does not apply to diagnosis of faulty sprag clutch for the lower compression engine, this indeed was the case and the engine was fixed as a result of this test.
You want the cable to take 200 amps without much sag, as someone posted, welding cables are a good option these days, especially short links where flexibility is important.
Ralph
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rickofudall
Joined: 19 Sep 2009
Posts: 1392
Location: Udall, KS, USA
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| Posted: Fri Oct 08, 2010 4:35 pm Post subject: AMPS? |
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Ralph et al, This is from the Rotax installation manual, page 114, 17.3.5) Electric starter:Wire from starter relay to the electric starter
- cross section of at least 16 mm squared (6AWG)
- output: 0.7 kW / 0.9 kW optional
page 115, 17.3.6) Starter relay
-switching current: max. 75 A (permanent)
max. 300 A (for 1 sec.)
Rick Girard
On Fri, Oct 8, 2010 at 4:01 PM, jetboy <sanson.r(at)xtra.co.nz (sanson.r(at)xtra.co.nz)> wrote:
| Quote: | --> RotaxEngines-List message posted by: "jetboy" <sanson.r(at)xtra.co.nz (sanson.r(at)xtra.co.nz)>
Minimum steady state cranking amps is 75 for the 912S
This is described in SB-912-042 R1
We did this test on a troublesome 912UL and got 71 amps. Although the SB does not apply to diagnosis of faulty sprag clutch for the lower compression engine, this indeed was the case and the engine was fixed as a result of this test.
You want the cable to take 200 amps without much sag, as someone posted, welding cables are a good option these days, especially short links where flexibility is important.
Ralph
--------
Ralph - CH701 / 2200a
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Float Flyr
Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland
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| Posted: Fri Oct 08, 2010 4:53 pm Post subject: AMPS? |
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According to AC43.13-1b p.11-3 the next current charted above, you always go
to the next higher draw (above 75A), is 100A the cable to be used is 4ga.
for runs up to 30 ft. That is the chart for intermittent flow. 2ga. allows
for current up to 150A., same run and for currents over 150A to 200A 1ga. is
called for. These calculations are for 20C (68F) higher temps require
larger cables.
Noel
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