# Why do EV motors still use SAE hardware and keyed shafts?



## onegreenev (May 18, 2012)

Because all those companies still sell replacement motors to industry. That is there bread and butter. The very few DC EV motors do not justify the change. I use an 11" Kostov Forklift Motor. Pure industry. Same with many AC motor setups. They are also designed for industry. The few designed for automobiles don't justify the change. The quantity sold for EV conversions are rather small. It's not like they are rolling off the shelf at breakneck speeds. Even for industrial use they are not rolling off the shelves. 

Pete


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## major (Apr 4, 2008)

Why do our road signs still use miles and miles per hour? 

Standards are great. So many to choose from.


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## poprock (Apr 29, 2010)

It would be a terrible turn of events if we all could have a worldwide agreed standard relating to anything. Who would we hate? You may have seen the Simpsons episode where Homer becomes the Grand Poobah of a secret society called the Stonecutters. In their anthem they say "we are the ones who keep the metric system down ".


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## samwichse (Jan 28, 2012)

I bet European/Asian ratchets are still 1/4", 3/8", 1/2" drive too. Come to think of it, I think wheel sizes are still in inches worldwide (or at best, metric converted, eg 381mm 15" wheels).

I guess the real answer is that some things are so universal, being rid of them is nearly impossible.

For example, forestry datasets will never go metric. When you want to track something like forest progression over 100 years, and the data is all in 2" size class... what do you do? Distance between permanent sampling plots? Chains! 12 inches in a foot, 16.5 feet in a rod, 4 rods in a chain.


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## Matej (Dec 4, 2015)

major said:


> Why do our road signs still use miles and miles per hour?


Because the US being a giant nation aka a giant market with its own weird standards forces international companies to create US-specific versions of their products, which plays a big role in stimulating the economic bubble that Americans live in. It is an indirect form of market control, as opposed to people shopping for best prices on anything worldwide and ordering their TV's directly from Korea. 

As samwichse points out, some things such as ratchet drives and wheel sizes (strangely, tire widths are in millimeters) have become so deep-rooted and internationally standardized that they are not likely to change. On the other hand, converting to metric hardware or learning speed limits in kilometers per hour is not the end of the world, as indicated by all the industries and countries that already survived it and would never wish to go back.

Yet as onegreenev points out, if the companies still make motors for industry, which I was not aware of, or if they do not really produce all the components in-house, that makes sense.
Time to go on a crusade to convert the forklift industry to metric!


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## jwiger (Oct 18, 2014)

Doesn't the UK still use miles on their roads and metric for everything else?


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## samwichse (Jan 28, 2012)

jwiger said:


> Doesn't the UK still use miles on their roads and metric for everything else?


And stone for people's weight.


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## jwiger (Oct 18, 2014)

samwichse said:


> And stone for people's weight.


-That's just madness.


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## Moltenmetal (Mar 20, 2014)

We Canadians are officially metric, but really work in three unit systems: SI/metric, Imperial and US customary. Hey, at least an imperial gallon of water weighs ten pounds...

When a unit system needs a correction constant to make F=m*a, it's a bit if an embarrassment if you ask me. But any standard is better than NONE...

What's your problem with SAE hardware? At least it's not Whitworth!

Nobody here uses metric hardware EXCEPT automotive.

Pipe is a great example. Pretty much worldwide, NPS dimensions are used, even though some people call them DN. Nothing about those dimensions makes any sense in any unit system until you're larger than 12" NPS- not the OD or the ID of any schedule matches anything. Same with steel sections- nominal size and weight per foot for wide flange I beams (W sections), channels or S sections etc. All with screwy dimensions for the flanges and webs. Angles and HSS at least make sense in inch dimensions.


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## AlexanderB (Nov 14, 2014)

samwichse said:


> I think wheel sizes are still in inches worldwide [...]
> I guess the real answer is that some things are so universal, being rid of them is nearly impossible.


I know Citroën tried to introduce a metric wheel size a few decades ago, it did not take off, and its very hard to find tires for, and/or people get their wheels machined to match "normal" tires. (tires and wheels pretty much have every dimension in mm, except the nominal wheel rim diameter.

We're probably not going to get rid of that anytime soon, no.



Moltenmetal said:


> Pipe is a great example. Pretty much worldwide, NPS dimensions are used, even though some people call them DN. Nothing about those dimensions makes any sense in any unit system


Aargh, yeah.


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