Positive Earth?

True enough Rohan, but all those comments I posted are from reputable sources & are in print, and I think you would agree they are legitimate reasoning, and scientific explanations that can easily be referenced from a high school physics class, but what I am trying to convey is, we dont really know why each brand of motorcycle did the change, or each brand of automobile, or the telephone companies did the change over. Some may have switched for scientific reasons, some just to comply with standardization, we may never really know why. There are several really compelling arguments each way (+and- earth).

If you read ALL the varying views out there in interweb land, there sure is a bunch of opinions.
They can't all be right....

Be nice to find some proper science fully quoted somewhere, with the experimental evidence to back it up.
Last time I looked, that didn't seem to occur too much - in anything that I could find anyway.

What is certain is that your bike needs one or the other and not both.

Funny, in the past when I threw up links from the BritBike forum that put a little light on Mr. Brolund, the moderator of this forum LAB deleted them. "Skip" learned the trick though and is using it himself.

The links I put up showed Skip at one point telling everyone how that when he needed magneto work done he always let an expert handle it, as he had never rebuilt one, then one year later he is telling everyone in the world that he is the expert and to send their magnetos to him so he can make the money "rebuilding" them.
Looking at his posts you can see he also goes through the same steep learning curve where Norton Dominators are involved, not even knowing the most basic technical details of them, to becoming an expert on them in a matter of weeks.

This is all related to Skip being a "businessman". I am sure that no matter who he is dealing with, whether he cobbling in windows for them or cobbling anything, he lets them know he is the "expert" they should shovel money at.

Brolund's only talent is Googling information then cutting it and pasting it on internet forums, as if no one else knew how to do such a thing for themselves.

That is what I find hilarious.

Okay LAB what do you have for me this time?

An intelligent man doesn't need to degrade others, as his knowledge & experience should stands on its own.
I have not " learned" a single thing from Ben Gradler despite his erroneous claims. He cant seem to just make a comment , without some childish rhetoric. This is why many moderators have to discipline him.

Magnetos: There is no secret that at one time I did not know how to fix magnetos. After nearly 75 rebuilds I still am not an expert, we never stop learning. To be clear, I never claimed to be, that is a lie repeated on this forum by one person only. I would be more than happy to discuss magnetos, advantages & disadvantages, troubleshooting, etc. on a new thread if anyone wishes to start one, rather than hijacking this thread about positive & negative earth.

Not sure why the personal attacks on me, I am sure Sigmund Freud has written something that may be of help, but thats another website altogether. I have done much for the Norton community for free, as I have been involved in various Norton clubs since the 70's and have worked on pre-Commando Nortons for more years than Ben Gradler, despite his claims of me being new to Dominators.

As to being paid for services rendered, I am sure Ben Gets paid for the work he does, I am certainly no different. Although I have sent hundreds of dollars of Norton parts to folks for free over the years, kind of a "pay it forward" thing with me.

Now that I have had to defend myself (as usual) lets talk about positive & negative ground shall we & lets try to stay on track with that subject.

I was brought up with mechanics at an early age when my father gave me lots of hands on time with his 1930 Ford Model A , various Nortons, and other automobiles that used positive earth. He had his explanations on pos vs. neg. earth & because of my fairly extensive collection (hoarding) of manuals & books & have found a number of "theories" about why the change was made, and yes, wikipedia & other internet sources have additional theories. The anode & cathode theory is very scientific & can be proven in any basic high school science or physics book, but the question is, is this the reason it was changed in cars & bikes? And also, did different companys change for different reasons? The majority of what I have read in my books & auto manuals (Chilton, Haynes, & Motors books) from the 1960's indicates it was mosly due to the radios, somewhat due to the theory of pos. earth causing more rust, and standardization . But again, just because it is in print doesn't make it so.

beng said:

Funny, in the past when I threw up links from the BritBike forum that put a little light on Mr. Brolund, the moderator of this forum LAB deleted them.

Okay LAB what do you have for me this time?

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You can both disagree with each other's point of view as much as you want, but just try to keep it civil-or the snippers will have to come out...again. :roll:

Triton Thrasher said:

What is certain is that your bike needs one or the other and not both.

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While this is VERY true !!! if you have one battery, what is not so clear is what happens if you have TWO batteries, and keep the wiring for them quite separate ?
Computers, as mentioned, have both a +5v and a -5v rail, and use a common earth.
As with all things electrical, nothing is ever as simple as it seems ?

I don't think there is anyone here who has not said something in error.
Can we keep the bickering for pub nights - to be settled in the usual fashion.
Leave that bit to your imagination...

Agreed Rohan .

Scientific facts are one thing & don't necessarily dictate what manufacturers do (ac vs. dc household voltage, vhs vs. beta, etc) Would it be fair to assume the primary reason for the change were to standardize the entire automotive/cycle industry rather than any particular science, like the decision on which side a bike should shift on?

I don't think its fair to 'assume' anything ?
We didn't see the sales pitch that produced this....

Why change the Norton generator systems over, when they had been like that for decades, and alternators didn't arrive (for Nortons) for 4 more years.
And none of the components had changed ?

Auctually, I was looking for opinions. It seems like it was circa 1957 when SAE began to RECOMMEND negative ground and 12 volt systems. It was circa 1960 when SAE changed that standard to say SHALL be negative ground. It took a while for the tractor, truck, and automotive industry to follow the revised SAE standard .

This topic was raised in multiple forums including here with several points of views and comments as to the integration or migration for the automobile industry to implement a positive ground versus a negative ground.

Several views/comments made on one versus the other such as wire and battery terminal corrosion, extending the plug life, etc could all be correct but again there is no substantiated evidence of such, this primarily due to lack of standards or general collective data and studies back then that one was better than the other.

Although the standard body such as SAE (Society of Automobile Engineers) was originally set in 1905 in the USA, it was just to promote an exchange of ideas onto other societies. In 1928 the idea for a society of engineers specializing in automobile electrical trade industry was address in the UK.

Since then these standard bodies had slowly implemented standard changes for the auto industry.

Last implementation by the main manufactures was also a slow process, it did not happen overnight. What we know is all major USA manufactures GM, Ford, Chrysler and their respective subsidiaries used either or system. However with the introduction of the 12 volt systems in the mid 50’s (1955/1956) the negative ground was predominant the setup in the automobile industry but not fully implemented by all.

In 1948, UK manufactures Star to use 12v electrical system, 1960 alternators started to replace the generators, 1965 the negative earth/ground was reintroduced.

I would suggest reading the “Automobile Electrical and Electronic Systems” by Tom Denton 3rd edition; it has a few notes on this topic, . This book can be found on-line.

skipsoldbikes said:

In 1948, UK manufactures Star to use 12v electrical system, 1960 alternators started to replace the generators, 1965 the negative earth/ground was reintroduced.
.

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Where are you quoting this from ?
Commandos were still positive earth until the end, circa 1977 or so.
Triumph had alternators in 1954, and some of their bikes had them in the 1940s ?
Most (British) bike makers had changed over before 1960.
The reason oft quoted is that Lucas had decreed they would not make generators any more.
And the move away from magnetos was because Lucas said they would not make them any more...

Rohan said:

Triton Thrasher said:

What is certain is that your bike needs one or the other and not both.

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Can we keep the bickering for pub nights -
...

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I don't know. Why do you ask me?

Rohan said:

skipsoldbikes said:

In 1948, UK manufactures Star to use 12v electrical system, 1960 alternators started to replace the generators, 1965 the negative earth/ground was reintroduced.
.

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Where are you quoting this from ?
Commandos were still positive earth until the end, circa 1977 or so.
Triumph had alternators in 1954, and some of their bikes had them in the 1940s ?
Most (British) bike makers had changed over before 1960.
The reason oft quoted is that Lucas had decreed they would not make generators any more.
And the move away from magnetos was because Lucas said they would not make them any more...

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He's talking about cars.

Can we keep the bickering for pub nights -

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Triton Thrasher said:

I don't know. Why do you ask me?

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That bit wasn't directed at you in particular, just part of general comments.
Unless you want to bicker ??!!

I thought I was agreeing with you....

Triton Thrasher said:

He's talking about cars.

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So the SAE was following British motorcycle practice, more or less.
Or, following an independent trajectory ??

The SAE info is from the standard of automotive engineers & the history of pos. versus neg. earth in the auto industry, which wad done to standardize the industry. Historically, such advances trickle down to motorcycles, agricultural engines, etc. The auto industry is where the money is, so they often tend to set the standard for similar industries (but not always). This is one aspect of the argument that actually has some written proof to back it up (SAE), but again, not necessarily the only influence on the decision. As you can see by the examples I gave, even after the standard was set, not everyone followed suit.

So Rohan, you have offered a counterpoint for many of the ideas, why do you think the change was made, & what proof do you have to offer?

skipsoldbikes said:

So Rohan, you have offered a counterpoint for many of the ideas, why do you think the change was made, & what proof do you have to offer?

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I don't know what this phrase actually means, in english, but when the british motorcycle industry went to alternators and semiconductors, the only types of diodes then commercially available were the positive earth type.

My Commando hasn't rotted away, and nor has the wiring, 40 years after it was made.
Positive earth electrics and all.
What more 'proof' do we need ?

I still have a few of the large square type selenium diodes, as used by the BSA Bantams ? in their charging systems - if you bought the battery option lighting system (?).
These are CONSIDERABLY earlier than your date for alternators in cars, so the US Industry would seem to be decades behind the bitish motorcycle industry... ?
So its debateable where the trickle-down effect is going.... ?

As we all know, selenium (and germanium) were the preceding technologies to the introduction of silicon in the semiconductor business.
Selenium Valley or Germanium Valley just doesn't have the same ring to it.

P.S. Didn't Triumphs build those wartime twin sidevalves with alternator electrics ?
That is even earlier again.

Hi Rohan, good post, but again, none of us can seem to come up with the elusive documentation (other than the SAE reference) that is set in stone. Even the SAE documents dont state why , or set an exact date, it just a means to standardize the auto industry.

As to the commando & the cathode/anode effect originally debated in the auto industry, your Commando surely has a much lower ampere battery, wouldnt that affect the theory somewhat ? We know the reaction takes place, but from what I understand it is accelerated when the metals are exposed to air & moisture. Keep in mind, the era of autos that were concerned about this effect used a bare wire woven earth strap, not a nicely insulated earth wire lie the Commando. I am not saying this is a legitimate concern to begin with, but that that was the discussion at the time (many moons ago).

As to British vs. US automakers being ahead, or behind on alternator technology or =/- ground issues; back then, every brand did what they wanted , not a lot of standardization. GM was probably the worst back then, for decades, they sold both positive & negative earth autos (ancient history). And positive ground vehicles continued in production up through the 1980's in Europe from various manufacturers.

Germanium Valley, now that's funny!!!

I assume you are referring to diodes in the alternators, the only real difference between a negative ground alternator and a positive ground alternator IS the direction of the diodes. It is true, the diodes have to be insulated from ground, but that's always the case. (Even in a negative ground alternator, only three of the diodes have grounded anodes, the other three have their anodes tied to the three legs of the stator.)

Some say the +/- earth was due to changes in auto radios power diodes, I believe that the early power transistors were mostly NPN. (Mainly because NPN has the arrow pointing in the "right" direction for most engineers' simple minds to understand.) However, it is not true that NPN transistors require "negative potential" at the collector. For an NPN transistor to be properly biased, the collector must be at a positive voltage relative to the base and emitter.

So, is it true that the almost simultaneous advent of semiconductors and negative grounding in the automotive world is mostly coincidence ?

This is a topic that comes up regularly on classic car & bike forums, & tractor forums, one thing is constant on them all, no conclusive evidence & the debate continues..........................

Nice post, GREAT COMMENTS & OPINIONS !!

skipsoldbikes said:

As to the commando & the cathode/anode effect originally debated in the auto industry, your Commando surely has a much lower ampere battery, wouldnt that affect the theory somewhat ?

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Does amperage come into it ?? How ??
I'm not aware that my battery is flowing any power other than into the ignition when its running.
And when its parked, the key is off, so the chassis is connected to the +ve of the battery only, no amperage whatsoever.
Or it would go flat.
So any amperage powering corrosion of any form is going to be miniscule ?

skipsoldbikes said:

I assume you are referring to diodes in the alternators, the only real difference between a negative ground alternator and a positive ground alternator IS the direction of the diodes. It is true, the diodes have to be insulated from ground, but that's always the case.

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British motorcycle electrics had a zener diode as the voltage control system.
That finned thingy under the tank on Trumpys, and the gold thing bolted to the Z plate on Commandos.
It was +ve earth - and bolted to the chassis, for heat dispersal, so there was no insulating away from that.
I'm not aware that Lucas even had -ve earth zener diodes until the late 1970s - for the Triumph T140E was it ?
And that was the core part of british motorcycle electrics that for a long time DEMANDED that they be +ve earth.
No radios on bikes - unless you have a GoldWing.
Wonder how Police radios got on...

BTW, this is the bit that makes Triumph motorcycles positive earth.
The bronzey looking thingie in the middle is a +ve earth semiconductor, a Lucas zener diode. Its not quite an inch across.
It dumps any excess voltage as heat, above a certain threshold volts (14.2 volts, is it ? Probably need to consult the Manual).
Commandos use exactly the same Lucas part, but fitted to a different heatsink.

Rohan said:

skipsoldbikes said:

riumphs build those wartime twin sidevalves with alternator electrics ?
That is even earlier again.

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No. They were post-War.