# Re: [EVDL] Overdiven 10hp AC



## EVDL List (Jul 27, 2007)

*Re: [EVDL] Overdiven 10hp AC*


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Overdiven 10hp AC*


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Overdiven 10hp AC*


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## EVDL List (Jul 27, 2007)

*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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## EVDL List (Jul 27, 2007)

*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?
> >
> ...


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## EVDL List (Jul 27, 2007)

*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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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Overdiven 10hp AC*



> Myles Twete wrote:
> > Morgan LaMoore offered:
> >
> > Let's compare some numbers. The AC-150 motor weighs 50kg (including
> ...


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## EVDL List (Jul 27, 2007)

*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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## EVDL List (Jul 27, 2007)

*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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## EVDL List (Jul 27, 2007)

*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
> ...


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## EVDL List (Jul 27, 2007)

*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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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Overdiven 10hp AC*


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Overdiven 10hp AC*


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## EVDL List (Jul 27, 2007)

*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.
> ...


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## EVDL List (Jul 27, 2007)

*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.
> ...


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## EVDL List (Jul 27, 2007)

*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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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Overdiven 10hp AC*


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Overdiven 10hp AC*


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## EVDL List (Jul 27, 2007)

*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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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Overdiven 10hp AC*

We say AC motor as if all AC motors are the same. Most of our
generalizations are about the ACIM, AC InductionMotor. (pssst, all
motors run on AC)
If someone can get there hands on a wound rotor slip ring AC motor in
the size we need for drag racing, well the race would be on!

ACIM motors are designed for one speed and more importantly one level
of slip. The reactance of the rotor is a compromise.
If you instead have a three phase slip ring tap on the wound rotor, you
can vary the reactance, even inject voltage to lock in syncronous. You
can get regenerate the slip energy and get 10X starting torque at less
than run amps.

I have books, but I couldn't find a good online reference. Most give
speed torque curves, but the important is when they overlay the amps on it.

http://en.wikipedia.org/wiki/Electric_motor



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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Overdiven 10hp AC*


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Overdiven 10hp AC*

> 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.
I'ld think the only way you are going to get 'contactive' liquid cooling on a DC motor is to use brushless DC. The oil can't be good when used with arching brushes.

But those are just as expensive to implement as the AC's I'll guess.

But that does beg the question. WHY are they so much more than DC? Just because?



Arak Leatham - Web and Desktop Systems Developer
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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Overdiven 10hp AC*

> ACIM motors are designed for one speed and more importantly one level
> of slip. The reactance of the rotor is a compromise.

You say ACIM as if all ACIM motors are the same. Industrial ACIM
motors are designed for one speed and one level of slip, but an ACIM
like the AC-150 is designed for 0 to 13000 RPMs at variable torque and
slip. It gets great performance because of that, but it also made it
much, much harder to design and requires more complicated controller.

That said, I don't know why people think a DSP and more silicon on an
induction motor controller is a bad thing. A DSP is about $10. The
extra silicon is expensive, but it's also a much more efficient
commutation system than brushes.

And yeah, other variants of AC motors (permanent magnet and slip ring)
are much easier to control than ACIM. They still require 3-phase
controller hardware, but it's easier to decide what signal to send:
just provide a sine wave of the desired voltage synchronized with the
mechanical rotation. There's no complications of deciding how much
slip to employ at the desired torque and speed or anything like that.
However, permenant magnets are expensive, and slip rings share some of
the same inefficiencies as DC (although they can do regen more easily
and are more efficient).

-Morgan LaMoore

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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Overdiven 10hp AC*

google doesn't find much on a lincon motor. got link?

5hp may be too little. a larger alternator perhaps. from a semi or worse.
cool project on the kart. do you have pictures of the electronics?
also a video on youtube of it driving would be cool

Dan



> Arak Leatham wrote:
> 
> >Nice chart, could you find a spec for any Lincon Liquid cooled to add in? Also a column for AC vs DC? I can't tell if the Etek is the DC or AC replacement. I'm guessing it's the DC from the RPM. B&S now only makes the AC, I believe.
> >
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Overdiven 10hp AC*

>If you have an inverter grade 10hp ac motor, like say from a CNC mill,
>Then you can push the hz higher and cool the losses you have and do>well. They are often water cooled already. >something like this(a little big) which gives 1500/6000 rpm means it>was made for VFD. 15hp cont,20hp 30min means a lot more! for 10seconds>ebay>130158862063 or 130158876810 >or a pair of these 170152432843
MAN! those first two are huge! The last one is more like it. 

If Direct liuid cooling works as advertized I'l want something like two 1hp servos converted to 10hp continuous each. Although that is 2x the hp that I acually need. 

I need to see if Lincon has such an offering yet...anyone have a R&D contact there?

Arak Leatham - Web and Desktop Systems Developer
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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Overdiven 10hp AC*

From: Arak Leatham
> I'd think the only way you are going to get 'contactive' liquid cooling
> on a DC motor is to use brushless DC. The oil can't be good when used with
> arcing brushes.

A liquid-cooled DC motor does not run the brushes in the liquid; only the windings and iron (which produce most of the heat) are liquid cooled.

There are three sources of heat in an electric motor. Resistive losses (from the resistance of the copper windings and brushes or slip rings if it has them), magnetic losses (hysteresis, magnetization, and core loss in the iron), and mechanical friction (bearings, wind resistance, internal fans, brush drag, etc.)

All practical motors are AC; a "DC" motor is just an AC motor with an internal DC-to-AC converter. An AC motor's published specs are slightly better than an equivalent DC motor only because the latter includes the size, weight, and efficiency of this internal DC-to-AC converter. The AC motor "hides" these losses in its external inverter.

For those that think a commutator and brushes are inefficient, consider this. If they were inefficient, they would burn up! But they don't -- brushes and commutators are surprisingly small and have relatively little cooling compared to the transistors in solid-state inverters. A brush has a 1-2 volt drop; the IGBTs used in most inverters have a 2-3 volt drop, and so are actually somewhat *less* efficient. We use them because they have other advantages; not because they are more efficient.

> But that does beg the question. WHY are they so much more than DC? Just
> because?

A standard off-the-shelf AC induction motor of a given horsepower is slightly smaller and cheaper than an equivalent DC motor, because it doesn't have the brushes or commutator. Otherwise, the two types have virtually identical materials and efficiencies.

But if you want an AC traction motor for an EV, everything changes. The motor uses better bearings, stronger materials, and better balancing to withstand 13,000 rpm instead of 3600 rpm. The windings are laboriously hand-packed to increase efficiency instead of being machine-wound. More expensive core material is used to allow higher frequency operation. The insulation is strengthened to withstand the higher voltages and temperatures produced by higher peak loads. The cooling system is considerably improved.

By the time they get done, not one single piece is the same as a stock AC motor. Now you have a hand-made motor, custom produced in very low quantities. No wonder it is expensive!


--
"Excellence does not require perfection." -- Henry James
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart-at-earthlink.net

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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Overdiven 10hp AC*


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Overdiven 10hp AC*



> --- Jeff Shanab <[email protected]> wrote:
> <snip>
> > If someone can get there hands on a wound rotor slip
> > ring AC motor in
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Overdiven 10hp AC*

> You say ACIM as if all ACIM motors are the same. Industrial ACIM
> motors are designed for one speed and one level of slip, but an ACIM
> like the AC-150 is designed for 0 to 13000 RPMs at variable torque and
> slip. It gets great performance because of that, but it also made it
> much, much harder to design and requires more complicated controller.
The higher quality materials used allow for different slip levels, even the rotor design can be made to have different characteristics at differnt slip levels by taking advantage of the fact that the depth of the magnetic penetration into the rotor is related to slip frequency.
> That said, I don't know why people think a DSP and more silicon on an
> induction motor controller is a bad thing. A DSP is about $10. The
> extra silicon is expensive, but it's also a much more efficient
> commutation system than brushes.
>
> And yeah, other variants of AC motors (permanent magnet and slip ring)
> are much easier to control than ACIM. They still require 3-phase
> controller hardware, but it's easier to decide what signal to send:
> just provide a sine wave of the desired voltage synchronized with the
> mechanical rotation. There's no complications of deciding how much
> slip to employ at the desired torque and speed or anything like that.
> However, permenant magnets are expensive, and slip rings share some of
> the same inefficiencies as DC (although they can do regen more easily
> and are more efficient).

The slip rings in a slip-ring motor don't actually do commutation and only deal with rotor current They can get away with a much harder brush with a higher silver content and the rings are smooth. The point is that you can vary the resistance and excess rotor energy in high slip situations is handled outside the rotor and can even be regenerated back onto the line during motoring operation. Variable frequency drives and the smarts of the dsp control have allowed the standard squirl-cage ACIM to cover enough applications to just about kill the market for slip-ring motors. They still are popular for applications with high inertial starting loads like rock crushers, elevators and some other large applications where they must start under load without pulling excessive amps and/or melting down the rotor. 

I think that special ability to accelerate a high inertial load would makes this particular type of ac motor like a dc motor off the line.

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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Overdiven 10hp AC*



> Peter Gabrielsson wrote:
> > The AC-150 motor is in fact air cooled, if that's what you were referring to.
> 
> Ah, I had missed that! Thanks for the correction.
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Overdiven 10hp AC*

Hi Lee,

You state some valid points I agree with and a few
where I disagree. 




> --- Lee Hart <[email protected]> wrote:
> <snip>
> > A brush has a
> > 1-2 volt drop; the IGBTs used in most inverters have
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Overdiven 10hp AC*

Hi Jeff,

You seem to propagate a common misconception here
about poles and torque. It is my opinion that pole
count increase does not increase torque density in
these double air gap motors. Torque is a function of
the total air gap area, flux density and current
density.

Let's stick with 60 Hz induction motors. If you have
a 5 hp rated 4 pole motor, it has a speed of 1800 RPM.
Let's neglect slip for simplicity. So it would have
a rated torque of 14.6 lb.ft. And a 5 hp rated 8 pole
motor would be 900 RPM and have a rated torque of 29.2
lb.ft. It would appear that doubling the pole count
has doubled the torque. Right?

But take a look at a major motor manufacturer's
catalog. The 5 hp, 4 pole motor is a 213 frame size,
115 lbs. The 5 hp, 8 pole motor is a 256 frame size,
211 lbs. Both TENV. The mass has nearly doubled for
twice the torque. The torque density is about the
same.

I'm sure you can find some examples which contradict
this example. Nameplate ratings can be dangerous. 
So, with particular cooling schemes, the power ratings
for motors with different pole counts may be in the
same frame size. This is due to the fact that the
rating is strictly dependent on the losses. So if the
motors are of equal efficiency, the power rating will
be the same. But the breakdown torque will also be
the same. You haven't increased the torque with more
poles, you're just rating it at a lower speed.

Regards,

Jeff M



> --- Jeff Shanab <[email protected]> wrote:
> 
> > This can only apply if you start with a good 10hp AC
> > motor to begin
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Overdiven 10hp AC*

>
> Hi Jeff,
>
> You seem to propagate a common misconception here
> 
I am not propagating any misconceptions here.
> about poles and torque. It is my opinion that pole
> count increase does not increase torque density in
> these double air gap motors. Torque is a function of
> the total air gap area, flux density and current
> density.
> 
For a given motor that can run as 4 or 8 pole you are agreeing that the
rpm drops in half with double the poles
And I think you also agree that hp = (rpm*torque)/5252
So the mathematics of this tend to show that if two motors have the same
HP, the product of the rpm and the torque must be the same.
1/2 the rpm means twice the torque.
> Let's stick with 60 Hz induction motors. If you have
> a 5 hp rated 4 pole motor, it has a speed of 1800 RPM.
> Let's neglect slip for simplicity. So it would have
> a rated torque of 14.6 lb.ft. And a 5 hp rated 8 pole
> motor would be 900 RPM and have a rated torque of 29.2
> lb.ft. It would appear that doubling the pole count
> has doubled the torque. Right?
> 
OK, you do agree. 
> But take a look at a major motor manufacturer's
> catalog. The 5 hp, 4 pole motor is a 213 frame size,
> 115 lbs. The 5 hp, 8 pole motor is a 256 frame size,
> 211 lbs. Both TENV. The mass has nearly doubled for
> twice the torque. The torque density is about the
> same.
> 
I wasn't talking about density and I assume what is going on here is
that the 4 pole can get by with lighter construction because it is not
made for the torque.
for example, a Nema 213 has a 1.125 or 1.375 and a 256 has a 1.375 to
1.625 (U or T designation)
> I'm sure you can find some examples which contradict
> this example. 
A lot I am afraid, as the primary equation determines this
But i think we can think it through also. common sense

ok, for a given pole pair they each apply a tug on the rotor 120 times a
second at 60hz, once for the positive swing of the arc and once for the
negative.
Sure the size of the poles makes a difference, but I am talking about
the given volume of motor. it still produces the same HP
but instead of energizing 1 pole pair, now we energize a second pair in
parallel, the torque doubles but the rotor now takes 2 cycles to turn a
revolution

> Nameplate ratings can be dangerous. 
> So, with particular cooling schemes, the power ratings
> for motors with different pole counts may be in the
> same frame size. This is due to the fact that the
> rating is strictly dependent on the losses.
And here is the point, if it is a wound rotor motor, the excess energy
(that would result in the heat that limits the amount of amps you can
put in for the amount of cooling you have), is brought out of the rotor.
> So if the
> motors are of equal efficiency, the power rating will
> be the same. 
Power the same agreed.
> But the breakdown torque will also be
> the same. You haven't increased the torque with more
> poles, you're just rating it at a lower speed.
> 
Sorry, I disagree. I could run a math proof, but I promised myself when
I graduated i wouldn't do any more of those. 
> Regards,
>
> Jeff M

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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Overdiven 10hp AC*



> Jeff Shanab wrote:
> 
> >> But the breakdown torque will also be
> >> the same. You haven't increased the torque with more
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Overdiven 10hp AC*

Personally, I think it's only a matter of test conditions.

ACP's motor is (realistically) not 50kW continuous.
It is mathematically 50 kW just because it spins fast.
It will indeed output 50 kW continuously as long as you
can keep up cooling it, but no reasonable air blower
can dissipate so much heat. Or, motor is continuously
red hot and just can tolerate that. Or the motor
is OK but the intake air must be -40'C.

To compare:

Twice as heavy Siemens 5135WS14 motors have similar torque, but rated
just 45kW continuous at 3500 PRM. Why? If they would choose to rate
them at 8000 RPM (as ACP's) with the same torque, *continuous* power 
sure would
be over 90 kW as long as it is being cooled off well enough.
But that's the issue, it can't be cooled with realistic water
flow rate and water temp. Water will just vaporize. 45kW is real
life number with quite high water temp already.

I wish ACP would publish how efficient motor itself is
at 8k RPM and 50 kW continuous output, what is its
temperature, air intake temp, and other test conditions.

Victor



> Lee Hart wrote:
> > Peter Gabrielsson wrote:
> >> The AC-150 motor is in fact air cooled, if that's what you were referring to.
> >
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Overdiven 10hp AC*

Hi Victor,

I have a few comments inserted. And, would you
contact me off list? I have sent product inquires to
you and never get a reply. Thanks.




> --- Victor Tikhonov <[email protected]> wrote:
> 
> > Personally, I think it's only a matter of test
> > conditions.
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Overdiven 10hp AC*



> --- Victor Tikhonov <[email protected]> wrote:
> 
> > Jeff Shanab wrote:
> >
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Overdiven 10hp AC*

Hi Jeff,

>From your original post: "Now take the traditional 4
pole motor and turn it into a 12 pole motor, same
amount of windings and iron and the torque triples".

That sounded like you were talking torque density to
me. Sorry if I misunderstood you.

Regards,

Jeff M




> --- Jeff Shanab <[email protected]> wrote:
> 
> <snip>
> > I wasn't talking about density
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Overdiven 10hp AC*

hey guys these motors are used on cnc machines that are high speed and they NEED A BUNCH of cooling those that have access to milling / drilling machine  check it out and the mystery will go away
----- Original Message ----- 
From: Jeff Major<mailto:[email protected]> 
To: Electric Vehicle Discussion List<mailto:[email protected]> 
Sent: Wednesday, October 03, 2007 9:26 AM
Subject: Re: [EVDL] Overdiven 10hp AC



Hi Jeff,

>From your original post: "Now take the traditional 4
pole motor and turn it into a 12 pole motor, same
amount of windings and iron and the torque triples".

That sounded like you were talking torque density to
me. Sorry if I misunderstood you.

Regards,

Jeff M




> --- Jeff Shanab <[email protected]<mailto:[email protected]>> wrote:
> 
> <snip>
> > I wasn't talking about density
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] Overdiven 10hp AC*

> hey guys these motors are used on cnc machines that are high speed and they NEED A BUNCH of

Well,


Granted CNC have many of the attributes in a number of motors, but most of them have some issues not useful for an EV. Like weight. Or, like you said, a massive cooling system. The biggest problem after weight is price. They are very expensive. Surplus and Used not withstanding.

I think all the best candidates can already be found at the online EV parts sales outlets right now. Likely none of them are direct rotor cooling. They could just opt for massive cooling systems instead.




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