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#54815 - 05/31/07 8:20 pm Positve earth (ground)  
Joined: Jul 2006
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Berticus Offline
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Berticus  Offline
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I was discussing electronic ignitions the other day and it occurred to me that I don't know why a lot of British bikes are +ve earth. Why +ve earth rather than -ve? Is there some technical reason or is it just a convention?

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#54816 - 05/31/07 8:30 pm Re: Positve earth (ground)  
Joined: Nov 2005
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Fisherman Offline
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Tennessee
My guess is that when the electrics were designed, there was a condensor or a zener that the positive side of was also the mounting hardware...

I'm sure that someone will come up with a technical explanation that makes perfect sense, but 300 million of us Yanks can't be wrong.

Bernicus (Bernie)


'Never argue with an idiot, they'll bring you down to their level, and beat you with experience'

'72 TR6
'12 Hinckley Scrambler
'95 FLHTC Road Sofa
#54817 - 05/31/07 8:54 pm Re: Positve earth (ground)  
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Alex Offline
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Seattle
A positively charged frame is actually somewhat more corrosion resistant, so why negative ground?


A smattering:
'53 Gold Flash
'67 Royal Star
'71 Rickman Metisse
'40 Silver Star
'37 Rudge Special
sixtyseventy Lightboltrocket road racer...and many more.
#54818 - 05/31/07 9:05 pm Re: Positve earth (ground)  
Joined: Jan 2006
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GrandPaul Online content
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Laredo (South) Texas, USA
Alex - spot on.


GrandPaul (does not use emoticons)
Author of the book "Old Bikes"
Too many bikes to list, mostly Triumph & Norton, some BSA & European
"The Iron in your blood should be Vintage"
#54819 - 06/01/07 2:11 am Re: Positve earth (ground)  
Joined: Aug 2001
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MikeG Online content
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New Hampshier USA
I think most of it was from convention (habit?) as well. A lot of early vehicles were positive ground, even over here. I have a 31 Ford thats 6V positive, don't think Ford change till after the war. It was most likely easier and cheaper for them to design around existing components rather than risk innovation/money on something different. g
MikeG


1960 BSA A10
2007 Suzuki Bandit
1957 A10
(Used to be a Triumph here)
71 Norton Commando
#54820 - 06/01/07 2:27 am Re: Positve earth (ground)  
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norbsa48503 Offline
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Flint,Mich
About 15 years ago there was a Flyer put out about this. I could never test it but it claimed that spark plugs were the reason. The single piece of paper proclaimed that plugs were 15% better performing in a positive ground system. More bang for the buck and dam the consequences. I think it came from some British car nuts.


norbsa
1960 TR6
1963 Super Rocket
1965 650 Star
1966 441
1968 Thunderbolt
1969 Twinkle 250
1972 Fastback
1974 Roadster
1970 S.S
Way too many BSA's not named
http://decentcycles.com
#54821 - 06/01/07 3:43 am Re: Positve earth (ground)  
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JD Offline
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I learn something new every day on this forum. Thanks guys for all the info!


Josh
#54822 - 06/01/07 11:37 am Re: Positve earth (ground)  
Joined: Oct 2006
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relicduke Offline
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Nova Scotia
Well,the +ground thing sure didn't keep British cars from rusting!
Along the same line crappy tire has an electric gizmo that is s'posed to keep your car from rusting


poverty is the mother of invention
#54823 - 06/01/07 12:46 pm Re: Positve earth (ground)  
Joined: Apr 2006
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SBoyd Offline
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Virginia, USA
"Why +ve earth rather than -ve?" Berticus

Why drive on the left instead of the right?
Why are English toggle switches "up for off"?
Why use the Whitworth system for fasteners?
Why, then, change to the US system just when the world is going to Metric?


Stop the insanity.
#54824 - 06/01/07 1:50 pm Re: Positve earth (ground)  
Joined: Jun 2002
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Stuart Online content
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Stuart  Online Content
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Scotland
Hi,

Quote:
Originally posted by SBoyd:
Why drive on the left instead of the right?
Roman chariots were driven with the driver standing on the right so, when they passed in opposite directions, it made sense for them to pass right-side to right-side, so they kept to the left of the road. The Romans conquered all of Western Europe but, even when they retreated, the various countries kept driving on the left.

When the French revolution ousted the ruling class and put ordinary people in power, they hated mainly the English and changed as much as they could to the opposite of what the English did, including driving on the right. Napoleon conquered all of Europe except Great Britain and Ireland, and spread the French habit of driving on the right.

Until Britain defeated France at the Battle of Waterloo in 1815, the two countries were the dominant colonial powers around the world. To a great extent, depending on which colonial power historically dominated a particular country still dictates which side of the road that country drives on today.

Quote:
Originally posted by SBoyd:
Why are English toggle switches "up for off"?
Why use the Whitworth system for fasteners?
During the Industrial Revolution, the British Empire or British commercial influence dominated most of the world, so the most of the world got what the British made. As well as coming up with the eponymous engineering fastener standard, Whitworth invented the micrometer, which made accurate repetetive manufacture to a standard possible.

Quote:
Originally posted by SBoyd:
Why, then, change to the US system just when the world is going to Metric?
At the time, the largest market, by far, for British automotive exports was the US, which refused to go metric ... at the time. :rolleyes:

Btw, do you know the entire metric system is based on a mistake? As well as the aforementioned driving on the right, the French revolutionaries decided they wanted an entirely new measurement system, based on one ten-millionth of the distance between the North Pole and the Equator via the centre of Paris. Unfortunately, the French astronomers and mathematicians cocked up (didn't have a micrometer wink ) and there are 10,000,800 metres between the North Pole and the Equator.

Hth.

Regards,

#54825 - 06/01/07 3:37 pm Re: Positve earth (ground)  
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SBoyd Offline
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Virginia, USA
Good going Stuart.
Now, translating for relicduke (above)
"crappy tire" is a little known (outside of Canada) chain store called "Canadian Tire". Selling everything from auto-parts to hockey skates.


Stop the insanity.
#54826 - 06/01/07 4:01 pm Re: Positve earth (ground)  
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Vox Teardrop Offline
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Indy
Stuart, nice copy and paste of wikipedia text.


95' Triumph Speed Triple
72' Triumph T120
64' BSA Lightning Rocket
#54827 - 06/01/07 5:54 pm Re: Positve earth (ground)  
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BruceinT.O. Offline
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Toronto, Canada
Hey SBoyd,

You've made me proud with your ability to interpret Canajun. Want a beer, eh?


Bruce

1968 Triumph Trophy
#54828 - 06/01/07 7:12 pm Re: Positve earth (ground)  
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Alex Offline
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Quote:
Originally posted by Stuart:
Btw, do you know the entire metric system is based on a mistake?
Not really: It's just that that measurement standard was soon replaced by another one...which, in turn, was replaced by yet another....which also was soon replaced by another...and so on. By that definition, it has been based on many mistakes.

Also, did you know that the puny inch has been based on the almighty meter since 1893?


A smattering:
'53 Gold Flash
'67 Royal Star
'71 Rickman Metisse
'40 Silver Star
'37 Rudge Special
sixtyseventy Lightboltrocket road racer...and many more.
#54829 - 06/01/07 8:34 pm Re: Positve earth (ground)  
Joined: May 2007
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Airedale Offline
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Airedale  Offline
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Black Isle , Scotland
"In the beginning" nearly all vehicles were negative earth.
Then in 1936 the change over to positive earth was effected on british cars and it was done primarily to cause a reduction in spark plug voltages.It has long been known that the sparking voltage of some designs of spark plug notably the pointed electrode type is appreciably less when the central electrode has a negative polarity than when it is positive.
Another reason for the change over was as this minnimised corrosion to the battery terminals and other connections in the system.The reasons however that prompted this change have now been eliminated by design, material and other modifications.for example this required negative spark polarity can now be obtained within modern coil designs irrespective of the earth polarity.and the corrosive nature of dissimilar battery connections has also been long overcome.

#54830 - 06/01/07 10:05 pm Re: Positve earth (ground)  
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BeezaBryan Online content
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Derbyshire UK
Quote:
Originally posted by Alex:
Also, did you know that the puny inch has been based on the almighty meter since 1893? [/QB]
If that is correct then another mistook was made.
1 Imperial inch = 25.4 mm

How can the Imperial inch be puny when it needs 25.4 of those millithings to equal it?


Blessed are the curious for they shall have adventures

It's not the destination, it's the journey.

Bryan
BSA Owners Club UK
Ohio Valley BSAOC USA


#54831 - 06/01/07 10:13 pm Re: Positve earth (ground)  
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Tom Bartoli Offline
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Tom Bartoli  Offline
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Posts: 100
Kissimmee, Florida (near Orlan...
As most engineering students learn early in their study is that there are two conventions used for direction of current flow.

The most common used today by Electrical Engineering students is known as "Conventional current flow"; that is, current is assumed to flow out of the positive terminal, thru the circuitry, and return to the negative terminal.

Another convention used mostly by Physicists is known as "Electron flow", where electrons flow out of the negative terminal and return to the positive terminal.

In days gone by the latter convention (Electron flow) was more prevalent and my guess is that's why the positive ground convention.

In any case, whatever circuitry is connected between the two terminals of the battery, neither the circuitry nor the battery cares which side is used as a "reference"... or, as we erroneously call it, "ground". Technically, the term ground is reserved for actual connections to "Earth"... like the third terminal (the round one) of the AC outlets in the house.
laugh


Tom - FL
05 Suzuki Bandit 1200S
#54832 - 06/01/07 10:14 pm Re: Positve earth (ground)  
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Alex Offline
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Alex  Offline

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Seattle
Quote:
Originally posted by beezabryan1:

How can the Imperial inch be puny when it needs 25.4 of those millithings to equal it?
...which is precisely why metric units are more accurate than imperial ones. laugh


A smattering:
'53 Gold Flash
'67 Royal Star
'71 Rickman Metisse
'40 Silver Star
'37 Rudge Special
sixtyseventy Lightboltrocket road racer...and many more.
#54833 - 06/01/07 11:45 pm Re: Positve earth (ground)  
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Airedale Offline
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Airedale  Offline
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Joined: May 2007
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Black Isle , Scotland
It is easy however to impress a girl with my 12 inches.
bragging over the metric equivalent however will lead to incomprehesion and derision!!!!!!!!!!

#54834 - 06/02/07 12:56 am Re: Positve earth (ground)  
Joined: Mar 2006
Posts: 135
tech 108 Offline
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tech 108  Offline
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Posts: 135
Florida
Hello from Tech 108, Gentlemen, lets get directly back to the topic. Why were Triumph motorcycles for the time being positive ground? The one bike that really personifies the Triumph Heritage is
the 5T Speedtwin designed by Edward Turner himself. Are you aware that the original bike was designed around a negative ground system? It wasn't until 1952 that the bike was converted for the reason and I quote from The Triumph Speedtwin and Thunderbird Bible by Henry Woolridge, pg. 48.
Quote( Triumph introduced positive earth electrics because the motor trade was of the opinion that less terminal corrosion took place when this arrangement was used. ) End Quote.
Mr. Turner would not have signed off on this change unless he believed it. Therefore I believe.

#54835 - 06/02/07 12:09 pm Re: Positve earth (ground)  
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Stuart Online content
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Stuart  Online Content
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Scotland
Hi,

Quote:
Originally posted by Vox Teardrop:
Stuart, nice copy and paste of wikipedia text.
Wikipedia is a child of the internerd; otoh, my expensive English classical education predates the internerd by at least a couple of decades.

Quote:
Originally posted by Alex:
Quote:
Originally posted by Stuart:
Btw, do you know the entire metric system is based on a mistake?
Not really:
What used to be *the* standard metre, made out of something costalotium with a coefficient of expansion virtually nil is still exhibited in an air-conditioned vault in Paris.

Quote:
Originally posted by Alex:
did you know that the puny inch has been based on the almighty meter since 1893?
The 'puny' inch was enshrined in medieval statute when England still ruled most of France; the metric system was devised by a bunch of uppity ex-colonial ingrates given their freedom by a benevolent England (something that was to repeat itself throughtout history :rolleyes: ). Britain only finally decided to go metric in 1965 (whereupon its automotive manufacturers promptly adopted the American engineering fastener standard :rolleyes: ) and is still beating off attempts by the French (most recently by having an EC Directive rescinded) to impose their flawed measurement system.

Hth.

Regards,

#54836 - 06/03/07 2:58 pm Re: Positve earth (ground)  
Joined: Sep 2006
Posts: 133
48 dingalinger Offline
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48 dingalinger  Offline
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Posts: 133
Victorville
Hey Gents;

Good noise here laugh

The electrons don't care if they are positive or negetive, they can only do their work with a path to ground.

Quote:
Originally posted by tech 108:
Hello from Tech 108, Gentlemen, lets get directly back to the topic. Why were Triumph motorcycles for the time being positive ground? The one bike that really personifies the Triumph Heritage is
the 5T Speedtwin designed by Edward Turner himself. Are you aware that the original bike was designed around a negative ground system? It wasn't until 1952 that the bike was converted for the reason and I quote from The Triumph Speedtwin and Thunderbird Bible by Henry Woolridge, pg. 48.
Quote( Triumph introduced positive earth electrics because the motor trade was of the opinion that less terminal corrosion took place when this arrangement was used. ) End Quote.
Mr. Turner would not have signed off on this change unless he believed it. Therefore I believe.
Negetive ground is common in the telecommunications industry. tech108 brings up a good point that its all about who's in charge.
Alexander Graham, The British, French, Spanish. Romans. Persians. The all have had influance.

I wonder what prize Mr. Sir Whitworth received for the addoption of his meassurement system from the Crown

Curse his system,,, His name lives!!!
g


'68 T120R
'66 A65L
Bob
it really doesn't matter to anyone, BUT ME
#54837 - 06/17/07 4:57 pm Re: Positve earth (ground)  
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Posts: 13
Spezialist Offline
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Spezialist  Offline
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Posts: 13
Middle of the Pacific
Quote:
Originally posted by tech 108:
Hello from Tech 108, Gentlemen, lets get directly back to the topic. Why were Triumph motorcycles for the time being positive ground? The one bike that really personifies the Triumph Heritage is
the 5T Speedtwin designed by Edward Turner himself. Are you aware that the original bike was designed around a negative ground system? It wasn't until 1952 that the bike was converted for the reason and I quote from The Triumph Speedtwin and Thunderbird Bible by Henry Woolridge, pg. 48.
Quote( Triumph introduced positive earth electrics because the motor trade was of the opinion that less terminal corrosion took place when this arrangement was used. ) End Quote.
Mr. Turner would not have signed off on this change unless he believed it. Therefore I believe.
Or just a simple dab of petrol to the connections and never again worry about acid bleed through.

#54838 - 06/17/07 10:57 pm Re: Positve earth (ground)  
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Posts: 804
andrewinpopayan Offline
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andrewinpopayan  Offline
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Halifax, Butt end of Europe
I want to sneak into the place in Paris and saw off a couple of feet of the costalotium bar and wieght it in for precious scrap to fund my next project.

Quote:
Negetive ground is common in the telecommunications industry. tech108 brings up a good point that its all about who's in charge.
Alexander Graham, The British, French, Spanish. Romans. Persians. The all have had influance.
Lucas should be added to the list. I remember that when car radio's first became available you either had a switch to select + or - ground or you bought the radio to suit the vehicle ground.


99% of carb problems are electrical.

1959 3TA

BMW R1150 Oilhead

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