EV Digest 3349
Topics covered in this issue include:
1) Re: Finally back online, newbie question @ 'hi-lo' controller
by "Joe Smalley" <[EMAIL PROTECTED]>
2) Re: Sparrow reborn
by "David Roden" <[EMAIL PROTECTED]>
3) Re: http://www.evworld.com/view.cfm?section=article&storyid=642Comments
by "David Roden" <[EMAIL PROTECTED]>
4) Re: Sparrow reborn
by "David Roden" <[EMAIL PROTECTED]>
5) Modifying my Sparrow motor
by Doug Weathers <[EMAIL PROTECTED]>
6) Re: Modifying my Sparrow motor How to shorten a shaft.
by Rod Hower <[EMAIL PROTECTED]>
7) Re: Modifying my Sparrow motor
by "Joe Smalley" <[EMAIL PROTECTED]>
8) Re: Did I torch my new old EV meter?
by "Roy LeMeur" <[EMAIL PROTECTED]>
9) Re: Did I torch my new old EV meter?
by "Joe Smalley" <[EMAIL PROTECTED]>
10) Re: AC/DC hybrid drive combo?
by Lee Hart <[EMAIL PROTECTED]>
11) Re: Modifying my Sparrow motor
by Doug Weathers <[EMAIL PROTECTED]>
12) Re: AC/DC hybrid drive combo?
by "Joe Smalley" <[EMAIL PROTECTED]>
13) Re: Sparrow rear suspension was reborn, Comments
by Alan Batie <[EMAIL PROTECTED]>
14) Re: Sparrow reborn
by Alan Batie <[EMAIL PROTECTED]>
15) O.T. job in New England for M.E. vehicle type
by Seth <[EMAIL PROTECTED]>
16) RE: Modifying my Sparrow motor
by David Brandt <[EMAIL PROTECTED]>
17) Re: transmission interchanges?
by "1sclunn" <[EMAIL PROTECTED]>
18) Re: FW: Did I torch my new old EV meter?
by "T Humphrey" <[EMAIL PROTECTED]>
19) Re: Sparrow rear suspension was reborn, Comments
by "John G. Lussmyer" <[EMAIL PROTECTED]>
--- Begin Message ---
Can you draw an ASCII schematic to show us how you propose to connect it up?
It might help us understand how you are going to implement it.
Joe Smalley
Rural Kitsap County WA
Fiesta 48 volts
NEDRA 48 volt street conversion record holder
[EMAIL PROTECTED]
----- Original Message -----
From: <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Tuesday, February 10, 2004 3:18 PM
Subject: Finally back online, newbie question @ 'hi-lo' controller
> Hello All,
>
> After a hiatus of several months, my Karmann Ghia conversion project and I
> are plugged back into the EV list, so please excuse if I echo any recent
> questions.
>
> The economization idea of the day is as follows; use two 96 volt packs in
> parallel with a Curtis 1221C-7401 controller, and then add two contactors
to
> bypass the controller and switch to series for 192 volt kick-in-the-pants
> performance.
>
> Parts needed: potbox with high and low pedal switches, DPDT contactor for
> series/parallell switching, and SPST contactor for bypassing the
controller.
>
> Who's been there & done that, or- what am I missing, besides the potential
to
> let out some Curtis smoke?
>
> Thanks,
>
> Jay Donnaway
> Woodstock, GA
> 1971 Karmann-Ghia body shell and rolling pan.....
>
>
--- End Message ---
--- Begin Message ---
On 9 Feb 2004 at 22:42, Rich Rudman wrote:
> We all said a Ac drive was the way to go but it cost twice the list
> price of the Sparrow.
IF they can get sales to take off, the cost has to come down. The reason
that AC drives cost so much (besides the extra silicon that goes into them)
is that the expensive engineering time is amortized over a few hundred
sales, instead of a few hundred ^thousand^ sales.
I always thought that Corbin should have had a chat with Josef Brusa. His
inverter designs (AMC-320/325) are close to a decade old now. Not only are
they mature and proven, but much of the engineering costs should be well in
the past. With a commitment to purchase enough of them, I wonder if Brusa
might be willing to negotiate a good price. I could be ^way^ off base with
that notion, though.
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David Roden - Akron, Ohio, USA
1991 Solectria Force 144vac
1991 Ford Escort Green/EV 128vdc
1970 GE Elec-trak E15 36vdc
1974 Avco New Idea rider 36vdc
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Est. yearly US cost to safeguard Persian Gulf oil supply: $50 billion
Est. 2001 value of US crude oil imports from Persian Gulf: $19 billion
-- Harper's Index, April 2002
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--- End Message ---
--- Begin Message ---
Subaru sells all over the world. It seems to me that the US is a limited
market, especially with our infamous taste for large vehicles. My guess is
that for such a petition to succeed, it would have to propose worldwide
sales of the EV. That of course will change its design and goals somewhat.
Maybe this effort should be a truly international one, working through EV
hobbyists and clubs in the US, Europe, and Asia.
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Want to unsubscribe, stop the EV list mail while you're on vacation, or
switch to digest mode? See http://www.evdl.org/help/
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David Roden - Akron, Ohio, USA
1991 Solectria Force 144vac
1991 Ford Escort Green/EV 128vdc
1970 GE Elec-trak E15 36vdc
1974 Avco New Idea rider 36vdc
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
All we learn from history is history repeats.
-- Andrew Ratshin
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--- End Message ---
--- Begin Message ---
On 10 Feb 2004 at 11:09, Tom Shay wrote:
> Corbin Motors did indeed build prototypes of Sparrows with AC drive systems.
They tried at least two AC drives - IIRC, MES-DEA (?not sure about that
name?) was one, and Nippon Denso the other. Claire Bell wrote of some of
the problems they had, but my memory won't call up what they were right now.
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Want to unsubscribe, stop the EV list mail while you're on vacation, or
switch to digest mode? See http://www.evdl.org/help/
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David Roden - Akron, Ohio, USA
1991 Solectria Force 144vac
1991 Ford Escort Green/EV 128vdc
1970 GE Elec-trak E15 36vdc
1974 Avco New Idea rider 36vdc
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Advertising (n): the science of arresting the human
intelligence for long enough to get money from it.
-- Stephen Leacock
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--- End Message ---
--- Begin Message ---
Hi all,
I bought my Sparrow motor from Bob, then turned around and bought my
motor adapter from Mike, telling him it was a regular 8inch ADC motor.
My bad - turns out the Sparrow's motor shaft is longer than the regular
motor's, and so Mike's adapter leaves the flywheel too far forward.
I promise to be less stupid in the future. This is pretty embarrassing.
I'm trying to figure out what to do now.
1) I could shorten the shaft on the Sparrow motor, either by myself
(how?) or by taking it to a machine shop.
2) Mike will sell me a deeper collar to bolt to the motor, for a fairly
sizeable figure.
3) Bob will sell me a much less expensive spacer that goes between the
motor and Mike's adapter. It wouldn't have the same profile as the
front of the motor, so Mike's adapter wouldn't fit as perfectly as it
does now.
4) I could have Bob or a machine shop build me a spacer that looks like
the motor to Mike's adapter. No idea what it would cost. Any guesses?
Did I miss something?
Does anyone have any suggestions for me?
Thanks,
Doug
--
Doug Weathers
Bend, OR, USA
http://learn-something.homedns.org:8100/weblog/
--- End Message ---
--- Begin Message ---
This is how I shorten stainless hardened shafts on
the motors at work (Ametek-Rotron).
Connect the motor to a DC source supply (12Vdc for a
96Vdc motor for example).
The motor runs at several thousand RPM's.
Get a high quality hacksaw blade, apply to rotating
shaft. Minutes later the excess shaft is gone.
Rod
--- Doug Weathers <[EMAIL PROTECTED]> wrote:
> Hi all,
>
> I bought my Sparrow motor from Bob, then turned
> around and bought my
> motor adapter from Mike, telling him it was a
> regular 8inch ADC motor.
> My bad - turns out the Sparrow's motor shaft is
> longer than the regular
> motor's, and so Mike's adapter leaves the flywheel
> too far forward.
>
> I promise to be less stupid in the future. This is
> pretty embarrassing.
>
> I'm trying to figure out what to do now.
>
> 1) I could shorten the shaft on the Sparrow motor,
> either by myself
> (how?) or by taking it to a machine shop.
>
> 2) Mike will sell me a deeper collar to bolt to the
> motor, for a fairly
> sizeable figure.
>
> 3) Bob will sell me a much less expensive spacer
> that goes between the
> motor and Mike's adapter. It wouldn't have the same
> profile as the
> front of the motor, so Mike's adapter wouldn't fit
> as perfectly as it
> does now.
>
> 4) I could have Bob or a machine shop build me a
> spacer that looks like
> the motor to Mike's adapter. No idea what it would
> cost. Any guesses?
>
> Did I miss something?
>
> Does anyone have any suggestions for me?
>
>
> Thanks,
>
> Doug
> --
> Doug Weathers
> Bend, OR, USA
> http://learn-something.homedns.org:8100/weblog/
>
--- End Message ---
--- Begin Message ---
Can you swap an armature from another motor into your case? If someone has a
motor with dead bearings, brushes, field or case, it might cost little to
nothing for the armature.
Joe Smalley
Rural Kitsap County WA
Fiesta 48 volts
NEDRA 48 volt street conversion record holder
[EMAIL PROTECTED]
----- Original Message -----
From: "Doug Weathers" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Tuesday, February 10, 2004 9:23 PM
Subject: Modifying my Sparrow motor
> Hi all,
>
> I bought my Sparrow motor from Bob, then turned around and bought my
> motor adapter from Mike, telling him it was a regular 8inch ADC motor.
> My bad - turns out the Sparrow's motor shaft is longer than the regular
> motor's, and so Mike's adapter leaves the flywheel too far forward.
>
> I promise to be less stupid in the future. This is pretty embarrassing.
>
> I'm trying to figure out what to do now.
>
> 1) I could shorten the shaft on the Sparrow motor, either by myself
> (how?) or by taking it to a machine shop.
>
> 2) Mike will sell me a deeper collar to bolt to the motor, for a fairly
> sizeable figure.
>
> 3) Bob will sell me a much less expensive spacer that goes between the
> motor and Mike's adapter. It wouldn't have the same profile as the
> front of the motor, so Mike's adapter wouldn't fit as perfectly as it
> does now.
>
> 4) I could have Bob or a machine shop build me a spacer that looks like
> the motor to Mike's adapter. No idea what it would cost. Any guesses?
>
> Did I miss something?
>
> Does anyone have any suggestions for me?
>
>
> Thanks,
>
> Doug
> --
> Doug Weathers
> Bend, OR, USA
> http://learn-something.homedns.org:8100/weblog/
>
--- End Message ---
--- Begin Message ---
From: Lee Hart <[EMAIL PROTECTED]>
Date: Tue Feb 10, 2004 10:16pm
Subject: Re: Did I torch my new old EV meter?
--------------------------------
Roy LeMeur wrote:
Show me _one_ OEM vehicle with an insulated single strand of wire run.
Look inside all of the electronics. No electronic component uses
stranded wire. But, the designers expect that the parts will be mounted
in some manner to avoid any movement.
--
"Never doubt that a small group of committed people can change the
world. Indeed, it's the only thing that ever has!" -- Margaret Meade
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
----------------------------
Hey! you guys are really giving me a hard time on this one. :-)
Or? Possibly, Lee is just supporting the point? :-)
A length of wire, traversing part of the vehicle, to deliver juice to
another component.
Again... it says _wire run_ not "trace on a circuit board" or "structural
connector"
or even "electronic component" or "PC board".
Or other things that are not supposed to move or be flexible.
We are talking about structural integrity under adverse shock and vibration
conditions.
I think, (and sometimes not that good :-) that I am still afloat here. :-)
Lee and Joe, I consider both of you to be gurus of this list.
And totally respect your input and opinions.
So... is it the nomenclature?
What is it I have stated here that don't quite seem to jive?
OK, well, maybe you are just propping me up here... :-)
Thanks for your input!
:-)
Roy LeMeur Olympia, WA
Updated!
My Electric Vehicle Pages:
http://www.angelfire.com/ca4/renewables/evpage.html
Informative Electric Vehicle Links:
http://www.angelfire.com/ca4/renewables/evlinks.html
_________________________________________________________________
Create your own personal Web page with the info you use most, at My MSN.
http://click.atdmt.com/AVE/go/onm00200364ave/direct/01/
--- End Message ---
--- Begin Message ---
It was the "SHOW ME ONE EXAMPLE" type of challenge that motivates people to
think.
Joe Smalley
Rural Kitsap County WA
Fiesta 48 volts
NEDRA 48 volt street conversion record holder
[EMAIL PROTECTED]
----- Original Message -----
From: "Roy LeMeur" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Tuesday, February 10, 2004 10:12 PM
Subject: Re: Did I torch my new old EV meter?
>
> From: Lee Hart <[EMAIL PROTECTED]>
> Date: Tue Feb 10, 2004 10:16pm
> Subject: Re: Did I torch my new old EV meter?
>
> --------------------------------
> Roy LeMeur wrote:
> >Show me _one_ OEM vehicle with an insulated single strand of wire run.
>
> Look inside all of the electronics. No electronic component uses
> stranded wire. But, the designers expect that the parts will be mounted
> in some manner to avoid any movement.
> --
> "Never doubt that a small group of committed people can change the
> world. Indeed, it's the only thing that ever has!" -- Margaret Meade
> --
> Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
> ----------------------------
>
>
>
> Hey! you guys are really giving me a hard time on this one. :-)
>
> Or? Possibly, Lee is just supporting the point? :-)
>
> A length of wire, traversing part of the vehicle, to deliver juice to
> another component.
>
> Again... it says _wire run_ not "trace on a circuit board" or "structural
> connector"
> or even "electronic component" or "PC board".
>
> Or other things that are not supposed to move or be flexible.
>
> We are talking about structural integrity under adverse shock and
vibration
> conditions.
>
> I think, (and sometimes not that good :-) that I am still afloat here.
:-)
>
> Lee and Joe, I consider both of you to be gurus of this list.
> And totally respect your input and opinions.
>
> So... is it the nomenclature?
>
> What is it I have stated here that don't quite seem to jive?
>
> OK, well, maybe you are just propping me up here... :-)
>
> Thanks for your input!
>
> :-)
>
>
>
>
>
> Roy LeMeur Olympia, WA
>
> Updated!
> My Electric Vehicle Pages:
> http://www.angelfire.com/ca4/renewables/evpage.html
>
> Informative Electric Vehicle Links:
> http://www.angelfire.com/ca4/renewables/evlinks.html
>
> _________________________________________________________________
> Create your own personal Web page with the info you use most, at My MSN.
> http://click.atdmt.com/AVE/go/onm00200364ave/direct/01/
>
--- End Message ---
--- Begin Message ---
This thread is wandering a bit, so I'll try to 'weave' it back together
again. :-)
It begins with the (slighly mad) idea that one has an EV with an AC
traction motor/controller *and* a second DC traction motor/controller,
making it an AC/DC hybrid. It thus has an AC drive for efficiency when
cruising, and a DC drive for fast accelleration.
Now, if the big AC and DC motors are coupled to each other and uncoupled
from the wheels, they could perhaps be used as a motor-generator for
battery charging. This could provide a high-power charger for very
little additional cost and weight (since the big expensive parts are
already in the car).
Victor contends that this won't work (isn't practical) because the AC
traction motor is built for high-frequency AC operation. It is built for
something like 6 KHz, so at 60 Hz you'd have to derate it 100:1, which
doesn't give you enough power to do anything useful.
I contend that an AC traction motor is actually built to run well on
anything from 20-200 Hz. The 6 KHz is only the PWM frequency, and not
what the motor actually sees.
_ _ _ _ _ _
AC_______| | | |___/\/\/\__________| | | |__
hot L1 R1 | | L3 |
|_ | |
_| > >
L2 _| > R2 > R3
_| > >
| | |
AC_________________________|____|___________|
neutral
Above is the equivalent circuit of an AC induction motor (view with
fixed-width font such as Courier). Only a single phase is shown. Each of
the values in the circuit corresponds to the following:
L1 = stator winding inductance (inductance with rotor removed)
R1 = stator winding resistance
L2 = magnetizing inductance (inductance with rotor spinning at
synchronous speed)
R2 = core loss equivalent resistance
L3 = rotor winding inductance (scaled to 1:1 turns ratio with stator)
R3 = rotor winding resistance (scaled to 1:1 turns ratio with stator)
plus the effective resistance of the mechanical load
Victor gave figures for L1 and R1 for one of his Siemens motors. They
were indeed very small; something like R1=0.01 ohms and L1=200uH. But
before we can predict what will happen if you connected such a motor to
120vac 60 Hz, we have to know the values of R2, R3, L2, and L3.
First, let's assume the rotor is stalled. Then R3 is simply the rotor
winding resistance, which is very low (just one shorted turn). We scale
it according to the turns ratio between the stator and rotor. A typical
motor might have 10 turns on the stator. Like a transformer, the
resistance scales as the square of the turns ratio. Thus, R3 is 100
times the actual rotor winding resistance. With most induction motors,
R3 will wind up being roughly equal to R1 i.e. R3=0.01 ohms.
Estimating L3 is much harder. There are large differences in rotor
inductance due to the type of laminations, the depth of the slots the
rotor bars are placed in, size of the air gap, and other factors. The
only way to know for sure is to look it up in the motor's engineering
specifications, or measure it in actual test.
The test proceedure is fairly straightforward. You lock the rotor so it
can't turn. You apply AC voltage with a variac, and adjust it for full
rated winding current. Then measure the stator voltage, current, and
phase angle. From these you can calculate the total values of L1+L3 and
R1+R3. Since L1 and R1 can be measured with the rotor removed, you can
therefore find L3 and R3.
But it is reasonable to assume that L3 is similar to L1. If so, then
L3=200uH. Knowing L1, L3, R1, and R3 lets us calculate the current if we
were to apply 120vac 60 Hz:
X = 2 pi f L = 2 x 3.14 x 60hz x 400uH = 0.15 ohms
R = R1 + R3 = 0.01 + 0.01 = 0.02 ohms
Z = sqrt(R^2 +X^2) = sqrt(0.02^2 + 0.15^2) = 0.15 ohms
I = E/Z = 120vac / 0.15ohms = 789 amps
So yes indeed; the STALLED ROTOR current is very high!
But, now let's assume there is no load on the motor. R3 includes the
equivalent resistance represented by the mechanical load as well. The
mechanical losses (friction and windage) are very small; like 3% of the
motor's horsepower rating. You didn't say what the rated HP of this
motor was; let's say it was 20 HP. Then R3 represents 20hp x 0.03 =
0.6hp x 746w/hp = 448 watts. At 120v, R3 = 120v^2 / 448w = 32 ohms.
R3 is so large compared to R1, L1 and L3 that it totally dominates. The
*in-phase* resistive AC current due to the frictional losses from the
unloaded rotor is only I = 448w / 120vac = 3.7 amps!
But we have left off L2 and R2. R2 is easier to estimate; it is the
equivalent resistance caused by core losses; the things that make the
core heat up. A high performance traction motor goes out of its way to
use very good laminations and construction techniques to keep these
losses low. So let's say they are only 3%. Thus, they account for
another 32 ohm resistor, and another 3.7 amps of stator current.
Now the big one; L2. This is the magnetization inductance; the apparent
inductance the motor has if the rotor is spun at synchronous speed. For
induction motors, L2 is on the order of 10-50 times the value of L1. You
can measure it by letting the motor run no-load, which makes R3 so large
that the reactive current thru L3+R3 is negligible. The resulting
reactive stator current is due to the sum of L1+L2.
L2 is what allows induction motors to be run from a fixed-voltage source
regardless of load. For best efficiency at light load, you *should*
apply a low AC voltage -- this is what the inverters in an EV AC drive
do. But you can also deliberately apply full voltage to an unloaded
motor -- this is what happens with normal induction motors on the AC
line. The current is high; but it is REACTIVE current, almost 90 degrees
out of phase. Thus, it does not produce heating or losses (except for
incidental losses in the resistance due to the high circulating
current).
OK, let's suppose L2 = 20 x L1 = 10 x 200uH = 4mH. What is the AC
current at 120vac 60 Hz with no load on the motor?
X = 2 pi f (L1+L2) = 2 x 3.14 x 60hz x (4mH + 200uH) = 1.58 ohms
I(x) = 120vac / 1.58ohms = 76 amps
R = R1 + (R2 | R3) = 0.01 + (32 | 32) = 16.01 ohms
I(r) = 120vac / 16ohms = 7.5 amps
In effect, the L and R are in parallel, because L1 and R1 are negligible
compared to L2, R2, and R3. So the total AC current is
I = sqrt(76^2 + 7.5^2) = 77 amps. We have a huge current, but the
resistive (loss-producing) portion is very small. The load is almost
purely inductive. This is exactly what you see with an unloaded
induction motor with excessive excitation voltage.
As you add load (i.e. load the AC motor with the DC motor as a generator
to charge the batteries, the resistive portion of the current increases.
The inductive portion actually drops, as a voltage divider is formed by
L1+R1 and L3+R3. But it will never get any better than a power factor of
about 0.8-0.9 (characteristic of any induction motor).
So, our questions become:
1. Can this motor stand 77 amps of continuous winding current? If not,
then you would need an autotransformer or other means to step down
the 120vac 60 Hz to reduce it to an acceptable level.
2. The power factor stinks at light load. You're not paying for the
power, but you'd need a hefty circuit and wiring (like 100-amp)
to supply it.
3. Can we load it heavily enough to get the power factor reasonable?
Or will we need to add capacitors or other means to get the power
factor down. My guess is that we'd want to use a big capacitor to
run one phase of the motor (as shown in the circuit diagram in a
previous email) both to provide the 3rd phase and to improve the
power factor.
To me, the bottom line is not, "Will it work". I am confident that you
*can* run an AC traction motor on plain old 120vac 60 Hz power with
relatively few extra parts. The motor will run, will produce a
significant fraction of its rated power, and it won't overheat or be
otherwise damaged.
The *real* question is, "Will it work well enough to bother with?" It
may require a big variac and big capacitor bank; that's already the
beginnings of a crude high-power charger. It might also require a fairly
high-power AC receptacle and cord to plug it in. And, it might require
extra switches or contactors to reconnect the motors between driving and
charging modes.
--
"Never doubt that a small group of committed people can change the
world. Indeed, it's the only thing that ever has!" -- Margaret Meade
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
On Tuesday, February 10, 2004, at 10:00 PM, Joe Smalley wrote:
Can you swap an armature from another motor into your case? If someone
has a
motor with dead bearings, brushes, field or case, it might cost little
to
nothing for the armature.
Good idea.
At a guess, probably not. The Sparrow motor has a tach sensor on the
back of the motor, which is attached to a sort of abbreviated tail
shaft. I have the engineering drawings for both motors, and the
standard 8incher doesn't seem to have a protruding tail shaft.
Then again, there's an 8incher with a tail shaft, isn't there? I don't
have a drawing for that one. I expect it would be too long anyway.
If there was another inexpensive Sparrow motor armature available, I
could experiment on it and leave my brand-new motor armature alone if
it didn't work out. Does anyone on the list have one?
Is it common for a motor to die in such a way that the armature is left
undamaged? That seems counter-intuitive to me.
Thanks for the response!
Doug
--
Doug Weathers
Bend, OR, USA
http://learn-something.homedns.org:8100/weblog/
--- End Message ---
--- Begin Message ---
Very informative, Lee. I have not analyzed AC motors to that depth before.
Thanks for posting it tonight.
Joe Smalley
Rural Kitsap County WA
Fiesta 48 volts
NEDRA 48 volt street conversion record holder
[EMAIL PROTECTED]
----- Original Message -----
From: "Lee Hart" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Wednesday, February 11, 2004 12:24 AM
Subject: Re: AC/DC hybrid drive combo?
> This thread is wandering a bit, so I'll try to 'weave' it back together
> again. :-)
>
> It begins with the (slighly mad) idea that one has an EV with an AC
> traction motor/controller *and* a second DC traction motor/controller,
> making it an AC/DC hybrid. It thus has an AC drive for efficiency when
> cruising, and a DC drive for fast accelleration.
>
> Now, if the big AC and DC motors are coupled to each other and uncoupled
> from the wheels, they could perhaps be used as a motor-generator for
> battery charging. This could provide a high-power charger for very
> little additional cost and weight (since the big expensive parts are
> already in the car).
>
> Victor contends that this won't work (isn't practical) because the AC
> traction motor is built for high-frequency AC operation. It is built for
> something like 6 KHz, so at 60 Hz you'd have to derate it 100:1, which
> doesn't give you enough power to do anything useful.
>
> I contend that an AC traction motor is actually built to run well on
> anything from 20-200 Hz. The 6 KHz is only the PWM frequency, and not
> what the motor actually sees.
> _ _ _ _ _ _
> AC_______| | | |___/\/\/\__________| | | |__
> hot L1 R1 | | L3 |
> |_ | |
> _| > >
> L2 _| > R2 > R3
> _| > >
> | | |
> AC_________________________|____|___________|
> neutral
>
> Above is the equivalent circuit of an AC induction motor (view with
> fixed-width font such as Courier). Only a single phase is shown. Each of
> the values in the circuit corresponds to the following:
>
> L1 = stator winding inductance (inductance with rotor removed)
> R1 = stator winding resistance
> L2 = magnetizing inductance (inductance with rotor spinning at
> synchronous speed)
> R2 = core loss equivalent resistance
> L3 = rotor winding inductance (scaled to 1:1 turns ratio with stator)
> R3 = rotor winding resistance (scaled to 1:1 turns ratio with stator)
> plus the effective resistance of the mechanical load
>
> Victor gave figures for L1 and R1 for one of his Siemens motors. They
> were indeed very small; something like R1=0.01 ohms and L1=200uH. But
> before we can predict what will happen if you connected such a motor to
> 120vac 60 Hz, we have to know the values of R2, R3, L2, and L3.
>
> First, let's assume the rotor is stalled. Then R3 is simply the rotor
> winding resistance, which is very low (just one shorted turn). We scale
> it according to the turns ratio between the stator and rotor. A typical
> motor might have 10 turns on the stator. Like a transformer, the
> resistance scales as the square of the turns ratio. Thus, R3 is 100
> times the actual rotor winding resistance. With most induction motors,
> R3 will wind up being roughly equal to R1 i.e. R3=0.01 ohms.
>
> Estimating L3 is much harder. There are large differences in rotor
> inductance due to the type of laminations, the depth of the slots the
> rotor bars are placed in, size of the air gap, and other factors. The
> only way to know for sure is to look it up in the motor's engineering
> specifications, or measure it in actual test.
>
> The test proceedure is fairly straightforward. You lock the rotor so it
> can't turn. You apply AC voltage with a variac, and adjust it for full
> rated winding current. Then measure the stator voltage, current, and
> phase angle. From these you can calculate the total values of L1+L3 and
> R1+R3. Since L1 and R1 can be measured with the rotor removed, you can
> therefore find L3 and R3.
>
> But it is reasonable to assume that L3 is similar to L1. If so, then
> L3=200uH. Knowing L1, L3, R1, and R3 lets us calculate the current if we
> were to apply 120vac 60 Hz:
>
> X = 2 pi f L = 2 x 3.14 x 60hz x 400uH = 0.15 ohms
> R = R1 + R3 = 0.01 + 0.01 = 0.02 ohms
> Z = sqrt(R^2 +X^2) = sqrt(0.02^2 + 0.15^2) = 0.15 ohms
> I = E/Z = 120vac / 0.15ohms = 789 amps
>
> So yes indeed; the STALLED ROTOR current is very high!
>
> But, now let's assume there is no load on the motor. R3 includes the
> equivalent resistance represented by the mechanical load as well. The
> mechanical losses (friction and windage) are very small; like 3% of the
> motor's horsepower rating. You didn't say what the rated HP of this
> motor was; let's say it was 20 HP. Then R3 represents 20hp x 0.03 =
> 0.6hp x 746w/hp = 448 watts. At 120v, R3 = 120v^2 / 448w = 32 ohms.
>
> R3 is so large compared to R1, L1 and L3 that it totally dominates. The
> *in-phase* resistive AC current due to the frictional losses from the
> unloaded rotor is only I = 448w / 120vac = 3.7 amps!
>
> But we have left off L2 and R2. R2 is easier to estimate; it is the
> equivalent resistance caused by core losses; the things that make the
> core heat up. A high performance traction motor goes out of its way to
> use very good laminations and construction techniques to keep these
> losses low. So let's say they are only 3%. Thus, they account for
> another 32 ohm resistor, and another 3.7 amps of stator current.
>
> Now the big one; L2. This is the magnetization inductance; the apparent
> inductance the motor has if the rotor is spun at synchronous speed. For
> induction motors, L2 is on the order of 10-50 times the value of L1. You
> can measure it by letting the motor run no-load, which makes R3 so large
> that the reactive current thru L3+R3 is negligible. The resulting
> reactive stator current is due to the sum of L1+L2.
>
> L2 is what allows induction motors to be run from a fixed-voltage source
> regardless of load. For best efficiency at light load, you *should*
> apply a low AC voltage -- this is what the inverters in an EV AC drive
> do. But you can also deliberately apply full voltage to an unloaded
> motor -- this is what happens with normal induction motors on the AC
> line. The current is high; but it is REACTIVE current, almost 90 degrees
> out of phase. Thus, it does not produce heating or losses (except for
> incidental losses in the resistance due to the high circulating
> current).
>
> OK, let's suppose L2 = 20 x L1 = 10 x 200uH = 4mH. What is the AC
> current at 120vac 60 Hz with no load on the motor?
>
> X = 2 pi f (L1+L2) = 2 x 3.14 x 60hz x (4mH + 200uH) = 1.58 ohms
> I(x) = 120vac / 1.58ohms = 76 amps
> R = R1 + (R2 | R3) = 0.01 + (32 | 32) = 16.01 ohms
> I(r) = 120vac / 16ohms = 7.5 amps
>
> In effect, the L and R are in parallel, because L1 and R1 are negligible
> compared to L2, R2, and R3. So the total AC current is
>
> I = sqrt(76^2 + 7.5^2) = 77 amps. We have a huge current, but the
> resistive (loss-producing) portion is very small. The load is almost
> purely inductive. This is exactly what you see with an unloaded
> induction motor with excessive excitation voltage.
>
> As you add load (i.e. load the AC motor with the DC motor as a generator
> to charge the batteries, the resistive portion of the current increases.
> The inductive portion actually drops, as a voltage divider is formed by
> L1+R1 and L3+R3. But it will never get any better than a power factor of
> about 0.8-0.9 (characteristic of any induction motor).
>
> So, our questions become:
>
> 1. Can this motor stand 77 amps of continuous winding current? If not,
> then you would need an autotransformer or other means to step down
> the 120vac 60 Hz to reduce it to an acceptable level.
>
> 2. The power factor stinks at light load. You're not paying for the
> power, but you'd need a hefty circuit and wiring (like 100-amp)
> to supply it.
>
> 3. Can we load it heavily enough to get the power factor reasonable?
> Or will we need to add capacitors or other means to get the power
> factor down. My guess is that we'd want to use a big capacitor to
> run one phase of the motor (as shown in the circuit diagram in a
> previous email) both to provide the 3rd phase and to improve the
> power factor.
>
> To me, the bottom line is not, "Will it work". I am confident that you
> *can* run an AC traction motor on plain old 120vac 60 Hz power with
> relatively few extra parts. The motor will run, will produce a
> significant fraction of its rated power, and it won't overheat or be
> otherwise damaged.
>
> The *real* question is, "Will it work well enough to bother with?" It
> may require a big variac and big capacitor bank; that's already the
> beginnings of a crude high-power charger. It might also require a fairly
> high-power AC receptacle and cord to plug it in. And, it might require
> extra switches or contactors to reconnect the motors between driving and
> charging modes.
> --
> "Never doubt that a small group of committed people can change the
> world. Indeed, it's the only thing that ever has!" -- Margaret Meade
> --
> Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
>
--- End Message ---
--- Begin Message ---
On Tue, Feb 10, 2004 at 06:11:40PM -0800, jerry dycus wrote:
> Any pics of the Sparrow rear swing arm,
> drive, around? Anyone know what parts, bearings,
> brake, they used by the wheel?
I don't know about parts, but here's pics from when I had to take mine
apart to replace the motor:
http://alan.batie.org/photos/nikon/000902-sparrow/
--
Alan Batie ______ alan.batie.org Me
alan at batie.org \ / www.qrd.org The Triangle
PGPFP DE 3C 29 17 C0 49 7A \ / www.pgpi.com The Weird Numbers
27 40 A5 3C 37 4A DA 52 B9 \/ spamassassin.taint.org NO SPAM!
To announce that there must be no criticism of the President, or that we
are to stand by the President, right or wrong, is not only unpatriotic
and servile, but is morally treasonable to the American public.
-Theodore Roosevelt, 26th US President (1858-1919)
--- End Message ---
--- Begin Message ---
On Tue, Feb 10, 2004 at 08:24:18PM -0800, Doug Weathers wrote:
> advance the timing on my Sparrow motor.
>
> So the next question is, how do I do this? I've seen a couple of
> messages go by that mentioned what to do, but they didn't make much
> sense to me. Can anyone point me to some explicit directions,
> including things like torque numbers for bolting it back together?
>
> Alan Batie and Otmar have posted some pictures - it looks pretty scary,
> what with taking the motor apart and drilling new holes in the casing.
> Is that really what's required?
Depends on the motor --- some of the ADC's already have the holes drilled
and tapped for different brush timings, but most of the Sparrow motors
didn't. If they're there, you do still have to take the end cap off,
rotate it and reattach it. If they're not, then you have to make them.
The cases are *really* hard stuff too --- one tap broke in the process
(the last picture of the set). All that said, the hardest part about it
was getting the motor out and noting where everything was. Once you have
the motor free, it's just uncap the ends, pull the case off, drill and
tap the holes 3/4" in the right direction and put it all back together.
http://alan.batie.org/photos/nikon/001023-motor/
--
Alan Batie ______ alan.batie.org Me
alan at batie.org \ / www.qrd.org The Triangle
PGPFP DE 3C 29 17 C0 49 7A \ / www.pgpi.com The Weird Numbers
27 40 A5 3C 37 4A DA 52 B9 \/ spamassassin.taint.org NO SPAM!
To announce that there must be no criticism of the President, or that we
are to stand by the President, right or wrong, is not only unpatriotic
and servile, but is morally treasonable to the American public.
-Theodore Roosevelt, 26th US President (1858-1919)
--- End Message ---
--- Begin Message ---
I know someone who is looking to hire a Mechanical Engineer. BSME or
equivalent, proficient in Solidworks, knowing sheet metal and not
scared of electronics is a plus. Needs to have 4+ years of experience.
Someone with practical vehicle design and industrial/automotive
electronics packaging would be well suited.
I will pass the info along, no I can't tell you exact details. Greater
New England, USA is the region.
E-mail me directly, please
Thanks for the bandwidth,
Seth Allen
AKA "the cynic"
"the other Seth"
"I lost on eBay too"
"Lee Hart ASCII art fan club member #47"
--- End Message ---
--- Begin Message ---
You need a spacer ring that matches the front of the motor and the hole
pattern on the adapter plate. Most adapter sets include these. It is a
very simple part, because the outer profile is unimportant, so it is usually
made from roud bar or mechanical tubing. It shouldn't cost you much at all.
> -----Original Message-----
> From: Doug Weathers [mailto:[EMAIL PROTECTED]
> Sent: Tuesday, February 10, 2004 11:24 PM
> To: [EMAIL PROTECTED]
> Subject: Modifying my Sparrow motor
>
> Hi all,
>
> I bought my Sparrow motor from Bob, then turned around and
> bought my motor adapter from Mike, telling him it was a
> regular 8inch ADC motor.
> My bad - turns out the Sparrow's motor shaft is longer than
> the regular motor's, and so Mike's adapter leaves the
> flywheel too far forward.
>
> I promise to be less stupid in the future. This is pretty
> embarrassing.
>
> I'm trying to figure out what to do now.
>
> 1) I could shorten the shaft on the Sparrow motor, either by myself
> (how?) or by taking it to a machine shop.
>
> 2) Mike will sell me a deeper collar to bolt to the motor,
> for a fairly sizeable figure.
>
> 3) Bob will sell me a much less expensive spacer that goes
> between the motor and Mike's adapter. It wouldn't have the
> same profile as the front of the motor, so Mike's adapter
> wouldn't fit as perfectly as it does now.
>
> 4) I could have Bob or a machine shop build me a spacer that
> looks like the motor to Mike's adapter. No idea what it
> would cost. Any guesses?
>
> Did I miss something?
>
> Does anyone have any suggestions for me?
>
>
> Thanks,
>
> Doug
> --
> Doug Weathers
> Bend, OR, USA
> http://learn-something.homedns.org:8100/weblog/
>
--- End Message ---
--- Begin Message ---
----- Original Message -----
From: "Jim Coate" <
> Does anyone know if the S-10 transmission engine mounting hole pattern
> is used on any other vehicles?
>
Why not keep the tranny,clutch ect and just mate the drive shafts , they can
be cut and fit to the drive shaft of your new EV . Sorry to hear about your
controller , My 600amp t- rex's were ,I believe turned down at the factory
, I'm running 216v and the most battery amps I see is about 200 , they also
go into terminal cut back all the time ( the fan will come on when the sun
warms the black hood ) with 100 battery amps then max. If I Turned the fun
knob back any further I'd have to get out and push :-) but I don't mine ,
just want them to last. I'm pulling a lot of weight with the trailer ect but
most of the time I'm pulling 50 amps and 100 while accelerating . I would
like to hear more on the idea of extra free wheeling diodes close to the
motor.
steve clunn
> To keep the next conversion a little easier I'd like to be able to use
> the existing motor adapter/clutch kits already developed for the S-10
> (ie Canadian Electric Vehicles). But I'm wondering if I can look at
> anything besides an S-10 as the donor vehicle, like Nissan or Toyota. Or
> are the tranny's themselves are interchangeable so can stick an S-10
> tranny in a different body, without having to design custom adapters?
>
>
> _________
> Jim Coate
> 1970's Elec-Trak
> 1992 Chevy S-10 BEV
> 1997 Chevy S-10 NGV
> http://www.eeevee.com
>
--- End Message ---
--- Begin Message ---
That's TRUE,
and so far nobody has shown an example that met all of the
parameters.
and that's Roy's point.
Stay Charged!
Hump
---------- Original Message ----------------------------------
From: Humphrey Timothy H Contr AFRL/IFEC
<[EMAIL PROTECTED]>
Date: Wed, 11 Feb 2004 14:17:47 -0000
>
>
>-----Original Message-----
>From: Joe Smalley [mailto:[EMAIL PROTECTED]
>Sent: Wednesday, February 11, 2004 1:13 AM
>To: [EMAIL PROTECTED]
>Subject: Re: Did I torch my new old EV meter?
>
>
>It was the "SHOW ME ONE EXAMPLE" type of challenge that motivates
people to
>think.
>
>Joe Smalley
>Rural Kitsap County WA
>Fiesta 48 volts
>NEDRA 48 volt street conversion record holder [EMAIL PROTECTED]
>
>----- Original Message -----
>From: "Roy LeMeur" <[EMAIL PROTECTED]>
>To: <[EMAIL PROTECTED]>
>Sent: Tuesday, February 10, 2004 10:12 PM
>Subject: Re: Did I torch my new old EV meter?
>
>
>>
>> From: Lee Hart <[EMAIL PROTECTED]>
>> Date: Tue Feb 10, 2004 10:16pm
>> Subject: Re: Did I torch my new old EV meter?
>>
>> --------------------------------
>> Roy LeMeur wrote:
>> >Show me _one_ OEM vehicle with an insulated single strand of
wire
>> >run.
>>
>> Look inside all of the electronics. No electronic component
uses
>> stranded wire. But, the designers expect that the parts will be
>> mounted in some manner to avoid any movement.
>> --
>> "Never doubt that a small group of committed people can change
the
>> world. Indeed, it's the only thing that ever has!" -- Margaret
Meade
>> --
>> Lee A. Hart 814 8th Ave N Sartell MN 56377
leeahart_at_earthlink.net
>> ----------------------------
>>
>>
>>
>> Hey! you guys are really giving me a hard time on this one. :-)
>>
>> Or? Possibly, Lee is just supporting the point? :-)
>>
>> A length of wire, traversing part of the vehicle, to deliver
juice to
>> another component.
>>
>> Again... it says _wire run_ not "trace on a circuit board" or
>> "structural connector" or even "electronic component" or "PC
board".
>>
>> Or other things that are not supposed to move or be flexible.
>>
>> We are talking about structural integrity under adverse shock
and
>vibration
>> conditions.
>>
>> I think, (and sometimes not that good :-) that I am still
afloat here.
>:-)
>>
>> Lee and Joe, I consider both of you to be gurus of this list.
And
>> totally respect your input and opinions.
>>
>> So... is it the nomenclature?
>>
>> What is it I have stated here that don't quite seem to jive?
>>
>> OK, well, maybe you are just propping me up here... :-)
>>
>> Thanks for your input!
>>
>> :-)
>>
>>
>>
>>
>>
>> Roy LeMeur Olympia, WA
>>
>> Updated!
>> My Electric Vehicle Pages:
>> http://www.angelfire.com/ca4/renewables/evpage.html
>>
>> Informative Electric Vehicle Links:
>> http://www.angelfire.com/ca4/renewables/evlinks.html
>>
>>
_________________________________________________________________
>> Create your own personal Web page with the info you use most,
at My
>> MSN. http://click.atdmt.com/AVE/go/onm00200364ave/direct/01/
>>
>
--- End Message ---
--- Begin Message ---
At 06:11 PM 2/10/2004, jerry dycus wrote:
Any pics of the Sparrow rear swing arm,
drive, around? Anyone know what parts, bearings,
brake, they used by the wheel?
If you dig around under "The Fleet" section on my site (casadelgato.com),
somewhere in there is the link to photos of my Sparrow swing-arm rebuild.
Also, the Sparrow list on Yahoo has lots of that info in the files area.
--
John G. Lussmyer mailto:[EMAIL PROTECTED]
Dragons soar and Tigers prowl while I dream.... http://www.CasaDelGato.com
--- End Message ---
