ac vs dc

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ac vs dc

Electric Blue auto convertions
what are you going to do when the burshless DC motors come out that will run at 12,000 RPMs complain about what then?? Is having that 5 % gain that important??? If you want to go broke doing an AC system go ahead . I have done trhem.
I do not see any gain over DC. ..the AD system was a pain in the ass to get working right , cost more than its worth. had NO speed advantages over DC..but then again my cell phone is 9 years old ..but it still works
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Re: ac vs dc

Cruisin
Maybe you know something that all the car manufacturers have missed. During my EV and Hybrid classes that I teach, I should have told all my students to disregard all the data on AC motors because they are obsolete. Try out a new leaf, then tell me DC is better. I have been doing both since 1978 and I can tell you, except for building a racing machine, AC has a lot more going for it, that is, unless you buy used 48v forklift motors, used curtis from a golf cart and a bunch of old floodies to save a $$. Its ALL about money.
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Re: ac vs dc

Cor van de Water
Hi Al,

It may be good to include the text you reply to
so that we have an idea *what* it is that upsets
you so much. I did not recall anybody use the term
obsolete that you use, so it looks like you are
stoking one of the old fires on EVDL, the debate
about AC vs DC, which has nothing to do about the
actual motor technology (physically every motor is AC,
but commutation is done in different ways)
but it has everything to do with available (used) motors
and controllers and the design choices that were made for
each of these controllers. You can make a DC motor with
the same parameters (torque, speed, efficiency, you name it)
as an AC motor. It is just that the selection is not always
that easy available or cheap.

Please stop the AC vs DC discussion as it appears to only
cause friction and no progress in EV building

Cor van de Water
Chief Scientist
Proxim Wireless Corporation http://www.proxim.com
Email: [hidden email]    Private: http://www.cvandewater.com
Skype: cor_van_de_water     XoIP: +31877841130
Tel: +1 408 383 7626        Tel: +91 (040)23117400 x203

-----Original Message-----
From: [hidden email] [mailto:[hidden email]] On
Behalf Of Cruisin
Sent: Saturday, August 20, 2011 5:39 PM
To: [hidden email]
Subject: Re: [EVDL] ac vs dc

Maybe you know something that all the car manufacturers have missed.
During my EV and Hybrid classes that I teach, I should have told all my
students to disregard all the data on AC motors because they are
obsolete. Try out a new leaf, then tell me DC is better. I have been
doing both since 1978 and I can tell you, except for building a racing
machine, AC has a lot more going for it, that is, unless you buy used
48v forklift motors, used curtis from a golf cart and a bunch of old
floodies to save a $$. Its ALL about money.

--
View this message in context:
http://electric-vehicle-discussion-list.413529.n4.nabble.com/ac-vs-dc-tp
3757013p3757831.html
Sent from the Electric Vehicle Discussion List mailing list archive at
Nabble.com.

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Re: ac vs dc

Mike Golub-2
In reply to this post by Cruisin
What class?

Sent from my iPhone

On Aug 20, 2011, at 4:38 PM, Cruisin <[hidden email]> wrote:

> Maybe you know something that all the car manufacturers have missed. During
> my EV and Hybrid classes that I teach, I should have told all my students to
> disregard all the data on AC motors because they are obsolete. Try out a new
> leaf, then tell me DC is better. I have been doing both since 1978 and I can
> tell you, except for building a racing machine, AC has a lot more going for
> it, that is, unless you buy used 48v forklift motors, used curtis from a
> golf cart and a bunch of old floodies to save a $$. Its ALL about money.
>
> --
> View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/ac-vs-dc-tp3757013p3757831.html
> Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com.
>
> _______________________________________________
> | Moratorium on drag racing discussion is in effect.
> | Please take those discussions elsewhere.  Thanks.
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> | REPLYING: address your message to [hidden email] only.
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Re: ac vs dc

EVDL Administrator
In reply to this post by Electric Blue auto convertions
It's not an intrinsic AC vs DC issue, but I'd recommend driving an EV with
regenerative braking before you make your decision.  

You may not agree, and it may be largely because I grew up driving ICEVs
with manual transmissions and solid engine braking - but I think regen makes
a conversion EV more civilized and more pleasant to drive.  

Regen comes "free" with almost all AC drives, and often with sepex DC too.  
Series DC drives usually return the most sheer grunt for the money, which is
great if your main objective is to accelerate the vehicle as fast as you
possibly can.  However, it's a major challenge to get series DC drives doing
regen in a stable manner.

David Roden - Akron, Ohio, USA
EVDL Administrator

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email address from the webpage http://www.evdl.org/help/ .
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Re: ac vs dc

Cor van de Water
I still drive manual transmission cars (my automatic
is borrowed to a friend so that I get to keep the manual)
and I have also driven two AC drive equipped cars for 3-4 years
(one a Prius and the other US Electricar truck)
I agree that the regen "feels" natural if you are used to the
engine braking, although I have found over the years of driving
that I tend to reduce my fuel consumption by making a moderately
quick acceleration to my target speed, then push in the clutch
to coast without drag from the engine, as often the next traffic
light requires a slowdown or other driving circumstances.
I tend to maintain my speed within 5 MPH as not to hinder the
flow of traffic, but saving on fuel by *avoiding* engine braking.
The same holds for AC drive, unless you have a good rapport with
the accelerator pedal, it is hard to keep it where you are coasting
as this requires careful foot-handling. I know of people who
drive a heavy vehicle and treat the accelerator as on/off switch
and by modulating it (2 sec ON, 3 sec OFF) maintain speed of the
vehicle. Very annoying and wasteful, but some have not mastered
a better technique (yet).

Cor van de Water
Chief Scientist
Proxim Wireless Corporation http://www.proxim.com
Email: [hidden email]    Private: http://www.cvandewater.com
Skype: cor_van_de_water     XoIP: +31877841130
Tel: +1 408 383 7626        Tel: +91 (040)23117400 x203

-----Original Message-----
From: [hidden email] [mailto:[hidden email]] On
Behalf Of EVDL Administrator
Sent: Sunday, August 21, 2011 10:05 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] ac vs dc

It's not an intrinsic AC vs DC issue, but I'd recommend driving an EV
with regenerative braking before you make your decision.  

You may not agree, and it may be largely because I grew up driving ICEVs
with manual transmissions and solid engine braking - but I think regen
makes a conversion EV more civilized and more pleasant to drive.  

Regen comes "free" with almost all AC drives, and often with sepex DC
too.  
Series DC drives usually return the most sheer grunt for the money,
which is great if your main objective is to accelerate the vehicle as
fast as you possibly can.  However, it's a major challenge to get series
DC drives doing regen in a stable manner.

David Roden - Akron, Ohio, USA
EVDL Administrator

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = EVDL
Information: http://www.evdl.org/help/ = = = = = = = = = = = = = = = = =
= = = = = = = = = = = =
Note: mail sent to "evpost" and "etpost" addresses will not reach me.
To send a private message, please obtain my email address from the
webpage http://www.evdl.org/help/ .
= = = = = = = = = = = = = = = = = = = = = = = = = = = = =


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