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Discussion Starter #5
Re: [EVDL] Overdiven 10hp AC

> 1. Would this cooling effect also increase the power of a DC motor?

I think so. Electric motors, both AC and DC, are mainly limited by
heat. So if you can cool it better, you can run at higher power
levels.

That said, that cooling method might interfere with proper operation
of the brushes, hindering commutation. If so, it obviously couldn't
work on DC motors.

> 2. Do AC motors offer greater performance? Reference this statement
> in the paper, "based on the fact that AC drive technology offered the
> highest performance to weight ratio and could be made cost effective
> for electric vehicles"
>
> Thanks again in advance.

Let's compare some numbers. The AC-150 motor weighs 50kg (including
cooling) and has a rating of 50kW continuous. That's 1kW/kg, which is
0.608 hp/lb.

ADC 6.7" = 16HP/85lbs=0.188 hp/lb
ADC 9.1" = 28.5HP/150lbs=0.19hp/lb
WarP 11" = 43HP/229lbs=0.188hp/lb (1 hour rating, not continuous)

That's a clear win for AC induction. However, AC induction motors
require more expensive/heavier electronics. We can factor that in,
too:

AC-150 electronics:
100A DC-DC, 20kW charger, motor controller: 66.1 lbs

EV equivalent:
DLS-45 45A DC-DC: 5.5 lbs
PFC-50 12kW charger: 42 lbs
Z1K-EHV controller: 29.5 lbs
total: 77 lbs

Oops! By using their 3-phase inverter as a charger and controller, the
AC motor actually requires less electronics weight than the AC system!

So the AC system is more efficient, has better power to weight, and
has regen. The downside is that it costs $15,000.

The only reasons to use DC over AC are cost and availability. Those
are important reasons, though.

-Morgan LaMoore

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Discussion Starter #6
Re: [EVDL] Overdiven 10hp AC

That's (2) DLS 45 or 55 rater, not one so even more weight.
Morgan LaMoore wrote:

>> 1. Would this cooling effect also increase the power of a DC motor?
>
> I think so. Electric motors, both AC and DC, are mainly limited by
> heat. So if you can cool it better, you can run at higher power
> levels.
>
> That said, that cooling method might interfere with proper operation
> of the brushes, hindering commutation. If so, it obviously couldn't
> work on DC motors.
>
>> 2. Do AC motors offer greater performance? Reference this statement
>> in the paper, "based on the fact that AC drive technology offered the
>> highest performance to weight ratio and could be made cost effective
>> for electric vehicles"
>>
>> Thanks again in advance.
>
> Let's compare some numbers. The AC-150 motor weighs 50kg (including
> cooling) and has a rating of 50kW continuous. That's 1kW/kg, which is
> 0.608 hp/lb.
>
> ADC 6.7" = 16HP/85lbs=0.188 hp/lb
> ADC 9.1" = 28.5HP/150lbs=0.19hp/lb
> WarP 11" = 43HP/229lbs=0.188hp/lb (1 hour rating, not continuous)
>
> That's a clear win for AC induction. However, AC induction motors
> require more expensive/heavier electronics. We can factor that in,
> too:
>
> AC-150 electronics:
> 100A DC-DC, 20kW charger, motor controller: 66.1 lbs
>
> EV equivalent:
> DLS-45 45A DC-DC: 5.5 lbs
> PFC-50 12kW charger: 42 lbs
> Z1K-EHV controller: 29.5 lbs
> total: 77 lbs
>
> Oops! By using their 3-phase inverter as a charger and controller, the
> AC motor actually requires less electronics weight than the AC system!
>
> So the AC system is more efficient, has better power to weight, and
> has regen. The downside is that it costs $15,000.
>
> The only reasons to use DC over AC are cost and availability. Those
> are important reasons, though.
>
> -Morgan LaMoore
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

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Discussion Starter #7
Re: [EVDL] Overdiven 10hp AC

Morgan LaMoore offered:

Let's compare some numbers. The AC-150 motor weighs 50kg (including
cooling) and has a rating of 50kW continuous. That's 1kW/kg, which is
0.608 hp/lb.

ADC 6.7" = 16HP/85lbs=0.188 hp/lb
ADC 9.1" = 28.5HP/150lbs=0.19hp/lb
WarP 11" = 43HP/229lbs=0.188hp/lb (1 hour rating, not continuous)

That's a clear win for AC induction.

______________________________________________________________________

More datapoints:

ETEK 8" = 8HP/20# = 0.4hp/#
LYNCH LEM200 8" = 10HP/23.5# = 0.43hp/#
PMG132 8" = 9.5HP/25# = 0.38hp/#

Not as good as the AC-150 rating, but likely more efficient and
substantially more output per pound than any of the series wound motors
mentioned.

-Myles Twete, Portland, Or.



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Discussion Starter #8
Re: [EVDL] Overdiven 10hp AC

Myles Twete wrote:
> Morgan LaMoore offered:
>
> Let's compare some numbers. The AC-150 motor weighs 50kg (including
> cooling) and has a rating of 50kW continuous. That's 1kW/kg, which is
> 0.608 hp/lb.
>
> ADC 6.7" = 16HP/85lbs=0.188 hp/lb
> ADC 9.1" = 28.5HP/150lbs=0.19hp/lb
> WarP 11" = 43HP/229lbs=0.188hp/lb (1 hour rating, not continuous)
>
> That's a clear win for AC induction.
>
But what are the peak powers for the different motors?
Generally, AC motors don't peak much higher than their continuous
rating, while DC can peak WAY higher than their continuous rating. This
usually means that a DC system can accelerate better than an equivalent
continuous power AC system.

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Discussion Starter #9
Re: [EVDL] Overdiven 10hp AC

So is this an apples to oranges comparison? I use an AC for a continuous hi=
gh out put, and can optionally use AC or a DC for low continuous with short=
high peaks? At short useages like drag racing the cheeper DC is just fine =
then?
=

As for me I want 30 minutes of freeway driving in arizona so I should go wi=
th AC motors? Looks like these wet-cooled AC motors are a good idea for me.=
Since I only need 7.5kw to go 55mph, maybe I only need a 15 or 20 hp AC mo=
tor? =

=

I need two on 'detalidon', I wonder if Lincon has two (cw,ccw) liquid coole=
d 10hp peak AC induction motors for me and at what what cost? If liquid coo=
led is the same weight as a 1hp AC motor then I'm likely to pay very little=
for it...(I hope)
=

My other option is something like two PM123 PMDC motors. Which set would we=
igh less?



Arak Leatham - Web and Desktop Systems Developer




Estimating, Point of Sale, Tracking, Reporting Applications> Date: Sun, 30 =
Sep 2007 20:22:04 -0700> From: [email protected]> To: [email protected]=
u> Subject: Re: [EVDL] Overdiven 10hp AC> > Myles Twete wrote:> > Morgan La=
Moore offered:> >> > Let's compare some numbers. The AC-150 motor weighs 50=
kg (including> > cooling) and has a rating of 50kW continuous. That's 1kW/k=
g, which is> > 0.608 hp/lb.> >> > ADC 6.7" =3D 16HP/85lbs=3D0.188 hp/lb> > =
ADC 9.1" =3D 28.5HP/150lbs=3D0.19hp/lb> > WarP 11" =3D 43HP/229lbs=3D0.188h=
p/lb (1 hour rating, not continuous)> >> > That's a clear win for AC induct=
ion.> > > But what are the peak powers for the different motors?> Generally=
, AC motors don't peak much higher than their continuous > rating, while DC=
can peak WAY higher than their continuous rating. This > usually means tha=
t a DC system can accelerate better than an equivalent > continuous power A=
C system.> > _______________________________________________> For subscript=
ion options, see> http://lists.sjsu.edu/mailman/listinfo/ev
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Discussion Starter #10
Re: [EVDL] Overdiven 10hp AC

> But what are the peak powers for the different motors?
> Generally, AC motors don't peak much higher than their continuous
> rating, while DC can peak WAY higher than their continuous rating. This
> usually means that a DC system can accelerate better than an equivalent
> continuous power AC system.

The AC-150 has a peak of 150kW, 3 times its continuous rating. Most
series-wound DC's I've looked at have a peak about 4 times their
rating. Of course, a DC motor will pretty much take as much power as
you can give it for short periods, as long as you let it cool off
after; that isn't true of AC motors. For vehicle purposes, however,
that generally doesn't matter. Killocycle should probably stick with
DC motors, but I think most other vehicles would be better off with
AC.

You can't look at normal industrial AC motors and compare them for EV
use. They just aren't designed for it; they're designed to be cheap to
make and run at a max frequency of 60Hz; they're too heavy for a car
and won't work well at high frequencies. You need a motor that's
designed to be lightweight and run at high frequencies, whether it's
the monster AC-150 or a 18HP golf-cart AC motor.

-Morgan LaMoore

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Discussion Starter #11
Re: [EVDL] Overdiven 10hp AC

Morgan LaMoore wrote:
>> 1. Would this cooling effect also increase the power of a DC motor?

> I think so. Electric motors, both AC and DC, are mainly limited by
> heat. So if you can cool it better, you can run at higher power
> levels.

Exactly. Just as for ICEs, liquid cooling increases the power-to-weight
ratio. It's not AC vs. DC; it's that the AC motor example happens to be
liquid cooled, and all the DC examples were air-cooled.

--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net

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Discussion Starter #12
Re: [EVDL] Overdiven 10hp AC

I still haven't looked into motor theory in details but seems to me that
AC's main power advantage is rpm because it's free of brushes. but it's
only speculation so far.

another angle worth considering is some permanent magnet DC motors which
seem to have much higher power density than the popular series motors.
the Etek being an example. unfortunately that's a bit on the small size
but at only 9kg it's quite impressive. Lemco has a very similar one but
a bit larger so it could work in a car but unfortunately they were
struck with rigor mortis in their brains when pricing it (around 1600$).
performance wise it seems to be near the ADC 6.7" which is quite nice
for 11kg (yes it's kilogram. it's time you learn proper units USA. if I
convert it for you you wont learn anything)
The ADC 6.7" L91 weighs 38.6kg

I'm piecing together a table of motor specs for comparison:
http://www.zev.dk/motor.htm (some values are guesstimations, some may
be wrong, some may be factory lies or too conservative)
(if you know some of the missing values or can correct some, let me know.)

so far I haven't added any AC motors because it seems they are all
ridiculously priced.

Dan

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Discussion Starter #15
Re: [EVDL] Overdiven 10hp AC

Kaido Kert wrote:

>The B&S Etek that you have on your page is actually cheaper in PMAC
>config, than in brushed.
>
>
yes and as it should be. both the etek's are reasonably priced. but pmac
requires a controller and the eteks are too small. make a 25kg version
of hte same and we would have something that will make the ICE guys
wonder where the motor is. they only see an alternator

as I said I'm still coming from the outside of motor theory but it looks
like permanent magnet motors has been overlooked in EVs
but maybe induction AC will be king

Dan

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Discussion Starter #16
Re: [EVDL] Overdiven 10hp AC

AC advantages are that yes, as you mentioned, they don't have brushes.
They are also usually designed for higher voltages, which in and of
itself doesn't mean much because you could have a 600 volt DC motor just
as easily as a 600v AC motor. They are designed for higher voltage so
they take less current, but anyway:

The one main advantage that I like with AC motors is that they are more
versatile. You can go from optimum full power output to full power regen
in almost no time at all, with no arcing and no troubles. The problem
with DC series motors is the brush timing if you wish to use them for regen.

The problem with AC motors is that the controllers depend on the motor
physics. It's slim pickings if you wish to get a traction AC
motor+controller (yes I know about MetricMind)

The other problem is that the controllers are more complicated, having
some multiple of silicon as a DC controller to get the same power output
- I think it's sqrt(3) * (amount of DC Si) - can't really remember. They
also have very sophisticated logic. Often they have digital signal
processors.



Dan Frederiksen wrote:
> I still haven't looked into motor theory in details but seems to me that
> AC's main power advantage is rpm because it's free of brushes. but it's
> only speculation so far.
>
> another angle worth considering is some permanent magnet DC motors which
> seem to have much higher power density than the popular series motors.
> the Etek being an example. unfortunately that's a bit on the small size
> but at only 9kg it's quite impressive. Lemco has a very similar one but
> a bit larger so it could work in a car but unfortunately they were
> struck with rigor mortis in their brains when pricing it (around 1600$).
> performance wise it seems to be near the ADC 6.7" which is quite nice
> for 11kg (yes it's kilogram. it's time you learn proper units USA. if I
> convert it for you you wont learn anything)
> The ADC 6.7" L91 weighs 38.6kg
>
> I'm piecing together a table of motor specs for comparison:
> http://www.zev.dk/motor.htm (some values are guesstimations, some may
> be wrong, some may be factory lies or too conservative)
> (if you know some of the missing values or can correct some, let me know.)
>
> so far I haven't added any AC motors because it seems they are all
> ridiculously priced.
>
> Dan
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

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Discussion Starter #17
Re: [EVDL] Overdiven 10hp AC

Dan,

> for 11kg (yes it's kilogram. it's time you learn proper units USA. if I
> convert it for you you wont learn anything)
> The ADC 6.7" L91 weighs 38.6kg

I agree with you Dan, however, the kilogram is a mass unit not a
weight unit so it should read, "The ADC 6.7" L91 has a 38.6kg mass."

Sorry, the Physics major in me comes out once in a while :)

David Nelson

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Discussion Starter #20
Re: [EVDL] Overdiven 10hp AC

I must thank you al for this information, it is excessively useful to me. YOU see I am advocating a very light vehicle and any excess weight matters mucho. Expecially anywhere in the drive train or payload.

THAT is how I could create a 250lb car (no body yet) using an engine from a 300lb motorcycle. Of course now I want it to be EV drive. Unfotunately that one will need to be a hybrid since it was not strong or roomy enough for a full set of batteries. With these postings I'm finding I may only add about 100lbs shifting to the hybrid form.

The proposed new one, if you remember my other postings, of course is 100% EV.



Arak Leatham - Web and Desktop Systems Developer




Estimating, Point of Sale, Tracking, Reporting Applications> Date: Mon, 1 Oct 2007 18:27:27 -0700> From: [email protected]> To: [email protected]> Subject: Re: [EVDL] Overdiven 10hp AC> > Dan,> > > for 11kg (yes it's kilogram. it's time you learn proper units USA. if I> > convert it for you you wont learn anything)> > The ADC 6.7" L91 weighs 38.6kg> > I agree with you Dan, however, the kilogram is a mass unit not a> weight unit so it should read, "The ADC 6.7" L91 has a 38.6kg mass."> > Sorry, the Physics major in me comes out once in a while :)> > David Nelson> > _______________________________________________> For subscription options, see> http://lists.sjsu.edu/mailman/listinfo/ev
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