EV Digest 3476
Topics covered in this issue include:
1) Re: Insight IMA 70kW Hack?
by Victor Tikhonov <[EMAIL PROTECTED]>
2) Re: help with EV motor data
by Jeff Shanab <[EMAIL PROTECTED]>
3) Re: one, or more, motors
by Victor Tikhonov <[EMAIL PROTECTED]>
4) Re: Help with EV motor data
by Victor Tikhonov <[EMAIL PROTECTED]>
5) RE: one, or more, motors
by "Andre Blanchard" <[EMAIL PROTECTED]>
6) Re: one, or more, motors
by Andrew Letton <[EMAIL PROTECTED]>
7) Re: one, or more, motors
by Victor Tikhonov <[EMAIL PROTECTED]>
8) Re: one, or more, motors
by Victor Tikhonov <[EMAIL PROTECTED]>
9) Re: [Fwd: Re: Fw: Two 8" vs 1 9"...Zombie Gets a BIG motor!]
by Victor Tikhonov <[EMAIL PROTECTED]>
10) Re: one, or more, motors
by Andrew Letton <[EMAIL PROTECTED]>
11) Re: Two 8" vs 1 9"...Zombie Gets a BIG motor!
by Martin Klingensmith <[EMAIL PROTECTED]>
12) Re: one, or more, motors
by seth <[EMAIL PROTECTED]>
13) RE: one, or more, motors
by "Andre Blanchard" <[EMAIL PROTECTED]>
14) Re: Simple regulator question
by Lee Hart <[EMAIL PROTECTED]>
15) How do I unsubscribe?
by [EMAIL PROTECTED]
16) Re: one, or more, motors
by Victor Tikhonov <[EMAIL PROTECTED]>
17) Re: one, or more, motors
by Victor Tikhonov <[EMAIL PROTECTED]>
18) Re: one, or more, motors
by seth <[EMAIL PROTECTED]>
19) Re: one, or more, motors
by Jim Phillips <[EMAIL PROTECTED]>
20) Re: Insight IMA 70kW Hack?
by Lightning Ryan <[EMAIL PROTECTED]>
21) RE: help with EV motor data
by Roger Stockton <[EMAIL PROTECTED]>
22) Re: Two 8" vs 1 9"...Zombie Gets a BIG motor!
by Otmar <[EMAIL PROTECTED]>
23) Re: Two 8" vs 1 9"...Zombie Gets a BIG motor!
by Jude Anthony <[EMAIL PROTECTED]>
24) Re: [Fwd: Re: Fw: Two 8" vs 1 9"...Zombie Gets a BIG motor!]
by "Mark Thomasson" <[EMAIL PROTECTED]>
25) Re: [Fwd: Re: Fw: Two 8" vs 1 9"...Zombie Gets a BIG motor!]
by Lee Hart <[EMAIL PROTECTED]>
26) Re: one, or more, motors
by Lee Hart <[EMAIL PROTECTED]>
27) Re: Beefing up contactors
by "David Chapman" <[EMAIL PROTECTED]>
28) Alternative vehicle drive
by Rod Hower <[EMAIL PROTECTED]>
29) Re: one, or more, motors
by Aaron Birenboim <[EMAIL PROTECTED]>
30) Re: Alternative vehicle drive
by Bob Siebert <[EMAIL PROTECTED]>
--- Begin Message ---
Lightning Ryan wrote:
I once heard that some motor guru though that the Honda IMA motor
would be capable of far more than 10kW, Is there any truth to it?
The IMA is rated at 10kW / 144v = ~70Amps from the 6.5Ah cells
which means the "weak link" is the batteries which are already
pushing hard at over 10C. So extra batteries would be needed,
something like 132Lbs worth of 12*13Ah Hawkers Genesis perhaps.
Insight's IMA will not handle 10 kW for too long - it is not meant
for continuous duty and thus does not have adequate cooling.
Also control has to give pulsating current for IMA to
counter-react ICE vibration (as done in stock Insight).
Just running on smooth 3 phases will shake whole unit
a lot.
--
Victor
'91 ACRX - something different
--- End Message ---
--- Begin Message ---
ok, that clears things up. I was finding massive differences in charts
and formulas.
I have the base formula's to build up from scratch but I would need to
know the wire,turns,insulation,laminate and mechanical data.
Can anyone help me out there? or just really good dyno data .
I am writing this myself to simultanously link
controller,battery,suspension, and motor components into it. I will
provide a variety of outputs like g charts, positoon vs time, speed vs
time, maximum throttle% vs distance etc.
If I can model it I can code it.
If I can get the data, I can model it.
--- End Message ---
--- Begin Message ---
Aaron Birenboim wrote:
It sure seems elegant to me if we can get rid
of the clutch/transmission/differentials for some
sort of simple reduction gear or belt to
drive shafts.
http://www.metricmind.com/images/mot4.jpg
http://www.metricmind.com/images/mot2.jpg
Do any available AC systems have series/parallel switching
available? (Zilla is DC...)
Just dreaming....
Huh? 3 phase in series with what? How about sync with other
3 phases?...
--
Victor
'91 ACRX - something different
--- End Message ---
--- Begin Message ---
Joe Smalley wrote:
You are using "Permanent Magnet Motor" equations.
Most EVs use either "Series Wound Motors" (with DC controllers) or
"Induction or Synchronous Motors" (with AC controllers).
The only motor that follows the "Permanent Magnet Motor" equations is the
synchronous motor. It only follows that model when the rotor current is held
constant. I don't know of any controllers that do that. Victor may know if
any do.
Sorry, I don't know. Siemens inverters keep the current variable,
thus allowing different torques at the same RPM per demand,like
uphill/downhill at the same speed/gear will require).
I can't imagine anyone building inverters differently.
--
Victor
'91 ACRX - something different
--- End Message ---
--- Begin Message ---
If you did a series/parallel switch on the windings in the AC motor it
should have the same effect it does on a DC system. You have greater low
end torque and/or higher RPM without having to go to a higher battery
voltage.
Thanks,
Andre' B. Clear Lake Wis.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Victor Tikhonov
Sent: Monday, April 19, 2004 4:41 PM
To: [EMAIL PROTECTED]
Subject: Re: one, or more, motors
Aaron Birenboim wrote:
> It sure seems elegant to me if we can get rid
> of the clutch/transmission/differentials for some
> sort of simple reduction gear or belt to
> drive shafts.
http://www.metricmind.com/images/mot4.jpg
http://www.metricmind.com/images/mot2.jpg
>
> Do any available AC systems have series/parallel switching
> available? (Zilla is DC...)
>
> Just dreaming....
Huh? 3 phase in series with what? How about sync with other
3 phases?...
--
Victor
'91 ACRX - something different
--- End Message ---
--- Begin Message ---
The Uniq Mobility "AC" ("Brushless DC"?) motor used in our and a number
of other early solar cars had such series/parallel windings.
cheers,
Andrew
Andre Blanchard wrote:
If you did a series/parallel switch on the windings in the AC motor it
should have the same effect it does on a DC system. You have greater low
end torque and/or higher RPM without having to go to a higher battery
voltage.
Thanks,
Andre' B. Clear Lake Wis.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Victor Tikhonov
Sent: Monday, April 19, 2004 4:41 PM
To: [EMAIL PROTECTED]
Subject: Re: one, or more, motors
Aaron Birenboim wrote:
It sure seems elegant to me if we can get rid
of the clutch/transmission/differentials for some
sort of simple reduction gear or belt to
drive shafts.
http://www.metricmind.com/images/mot4.jpg
http://www.metricmind.com/images/mot2.jpg
Do any available AC systems have series/parallel switching
available? (Zilla is DC...)
Just dreaming....
Huh? 3 phase in series with what? How about sync with other
3 phases?...
--- End Message ---
--- Begin Message ---
Andre Blanchard wrote:
If you did a series/parallel switch on the windings in the AC motor it
should have the same effect it does on a DC system.
In short, you cannot do that, because at least:
1. the frequency in general is
different for both motors. There is 6 phase (dual 3 phase)
350 kW Elfa inverter http://www.metricmind.com/images/elfa.jpg
which handles two motors simultaneously,
2. Stator windings are connected in a star or delta configuration,
there is no "start" AND end of the same winding available.
This may be arranged, but the reason 1 still applies.
You have greater low
end torque and/or higher RPM without having to go to a higher battery
voltage.
The whole point of using AC motors and high enough voltage is
to *avoid* all this series-parallel stuff being debated today.
--
Victor
'91 ACRX - something different
Thanks,
Andre' B. Clear Lake Wis.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Victor Tikhonov
Sent: Monday, April 19, 2004 4:41 PM
To: [EMAIL PROTECTED]
Subject: Re: one, or more, motors
Aaron Birenboim wrote:
It sure seems elegant to me if we can get rid
of the clutch/transmission/differentials for some
sort of simple reduction gear or belt to
drive shafts.
http://www.metricmind.com/images/mot4.jpg
http://www.metricmind.com/images/mot2.jpg
Do any available AC systems have series/parallel switching
available? (Zilla is DC...)
Just dreaming....
Huh? 3 phase in series with what? How about sync with other
3 phases?...
--- End Message ---
--- Begin Message ---
Andrew Letton wrote:
The Uniq Mobility "AC" ("Brushless DC"?) motor used in our and a number
of other early solar cars had such series/parallel windings.
cheers,
Andrew
Series/parallel with what? With other motor's winding and using
single controller? How then do you feed different frequencies in two
windings (REQUIRED for stepper motors to run at different speeds)?
For induction motors slip allows more deviation between
actual rotor speed and stator windings frequency, but not by much.
--
Victor
'91 ACRX - something different
--- End Message ---
--- Begin Message ---
[EMAIL PROTECTED] wrote:
Soon after I get hot batteries again, I plan to jump to a very
high voltage AC drive (wound rotor) and go around all this brush nonsense
completely. Why mess with brushes and commutators when you can do a much
better job with transistors?
Bill, how much power do you want and how bad (and soon) do you want it
(i.e. how much are you willing to pay)? Talk to me off-line if you want.
What is your weight limit?
--
Victor
'91 ACRX - something different
--- End Message ---
--- Begin Message ---
Sorry Victor, but I don't remember the schematic and layout of the
windings; I was more involved with the mechanical side of things on that
car. There must be some sparky on the list who is familiar with those
1991 vintage Uniq Mobility motors...
cheers,
Andrew
Victor Tikhonov wrote:
Andrew Letton wrote:
The Uniq Mobility "AC" ("Brushless DC"?) motor used in our and a
number of other early solar cars had such series/parallel windings.
cheers,
Andrew
Series/parallel with what? With other motor's winding and using
single controller? How then do you feed different frequencies in two
windings (REQUIRED for stepper motors to run at different speeds)?
For induction motors slip allows more deviation between
actual rotor speed and stator windings frequency, but not by much.
--- End Message ---
--- Begin Message ---
I have heard the term 'rail' several times and I don't know what it is,
could you tell me?
[EMAIL PROTECTED] wrote:
No one has tried twin small motors in a rail with a Zilla 2000.
The math says it should be quicker... Much quicker.
_ /| Bill "Wisenheimer" Dube'
\'o.O' <[EMAIL PROTECTED]>
=(___)=
U
Check out the bike -> http://www.KillaCycle.com
--
--
Martin Klingensmith
http://infoarchive.net/
http://nnytech.net/
--- End Message ---
--- Begin Message ---
No, series/paralel in the same motor. Solectria had it in their BRLS
line of motors as well. I used it personally. I don't think the
controller was smart enough to require knowing if it was in series mode
or parallel mode. Basically got you 2 different voltage and torque
constants for the motor. A nice thing considering the state of MOSFET
design circa 1991.
Seth
Victor Tikhonov wrote:
>
> Andrew Letton wrote:
>
> > The Uniq Mobility "AC" ("Brushless DC"?) motor used in our and a number
> > of other early solar cars had such series/parallel windings.
> > cheers,
> > Andrew
>
> Series/parallel with what? With other motor's winding and using
> single controller? How then do you feed different frequencies in two
> windings (REQUIRED for stepper motors to run at different speeds)?
>
> For induction motors slip allows more deviation between
> actual rotor speed and stator windings frequency, but not by much.
>
> --
> Victor
> '91 ACRX - something different
--- End Message ---
--- Begin Message ---
Comments inserted.
See you tomorrow.
Thanks,
Andre' B. Clear Lake Wis.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Victor Tikhonov
Sent: Monday, April 19, 2004 5:36 PM
To: [EMAIL PROTECTED]
Subject: Re: one, or more, motors
> Andre Blanchard wrote:
>
> > If you did a series/parallel switch on the windings in the AC motor it
> > should have the same effect it does on a DC system.
>
> In short, you cannot do that, because at least:
>
> 1. the frequency in general is
> different for both motors. There is 6 phase (dual 3 phase)
> 350 kW Elfa inverter http://www.metricmind.com/images/elfa.jpg
> which handles two motors simultaneously,
>
> 2. Stator windings are connected in a star or delta configuration,
> there is no "start" AND end of the same winding available.
> This may be arranged, but the reason 1 still applies.
I was talking series/parallel switching the windings of one motor not two.
I have done it many times when changing machine tools over from 480 to 240,
if it can be done on a 60hz single speed motor it can be done on a variable
frequency/speed motor. The controller just has to be told how to do it. It
could also be a star/delta switch which has been done on machine tool
spindles.
> > You have greater low
> > end torque and/or higher RPM without having to go to a higher battery
> > voltage.
>
> The whole point of using AC motors and high enough voltage is
> to *avoid* all this series-parallel stuff being debated today.
The whole point of using AC motors is to be high tech and have real nice
regen. High voltage takes more expensive silicon in both the speed control
and the charging system, and lets not forget fuses, contactors, and
connectors. Bucking high voltage down for high current slow speed operation
takes fast expensive silicon. Being high tech is not the only or always the
best solution to a problem but it is what seems to attract the most
attention. I am not saying that AC is not a good way to go just that AC
does not need to mean high voltage.
> --
> Victor
> '91 ACRX - something different
>
>
> > Thanks,
> > Andre' B. Clear Lake Wis.
--- End Message ---
--- Begin Message ---
Christopher Zach wrote:
> Say you have three batteries. Two are 50% charged, and one is 90%.
> Maybe the third one has lousy capacity. So you charge away at 20
> amps until the voltage tapers off to say 45 volts at full charge.
>
> Battery 1 hits 15 volts (charged), but batteries 2 and 3 are still
> at 13 volts. So the charger keeps rolling in 20 amps, trying to
> bring the pack to full power.
The scenario you describe is real; it's what happens if the batteries
somehow get out of balance. This can happen from tapping the pack, just
after replacing a battery, or when some batteries are much newer or
warmer than the others.
But, it's unlikely that they can be as far off as 50% and 90% SOC unless
you just replaced a battery, are tapping the pack, the car has sat idle
a long time, or you just had some kind of catastrophic event (like
overdischarging and reversing a cell).
If your balancing system is working, it will push the batteries toward
balance a little bit on every charge cycle. It may not correct a 40% SOC
imbalance on a single cycle, but it should be able to correct it 5% or
so on each charge cycle (at 5% per cycle, it may take 8 charge cycles to
bring the 'stray' back into the flock).
> Now battery 1 is charged, but still has 20 amps rolling thru it.
> So the voltage on this battery goes up. Since the lower two are
> still sitting at 13 volts, it could go up to 18 volts and the
> charger would still see a pack voltage of 44 volts and still keep
> rolling on the current. Now you have a battery that is pulling 18
> volts, 20 amps, and is in the uncomfortable position of being a
> massive CC wreck.
Right! Stand by for the Kaboom!
What will really happen is that a fully charged battery will not carry
20 amps of charge current no matter what you push the voltage to; at
least, not for long! If you connected a constant-current 20-amp charger,
the battery's voltage will go to 15v... 20v... 30v... and somewhere
about this time the electrolyte begins boiling and the lid blows off!
> How can a regulator help here?
Obviously it can't. Even if it could safely bypass 20 amps, then the
battery would be left sitting at 15v for hours until the rest of the
pack finishes charging. The battery could easily go into thermal runaway
during this time.
> Unless the reg could tell the charger to back off
Exactly!
> If only there were a way to essentially say "Ok, this battery will
> stay at 15 volts now." then the other batteries could come up to
> steam.
Right. Rich added an output for this kind of signal to his latest (Mark
2?) regulator boards. My zener-lamp regulator has the light bulb; it
lights up the battery box when the first one lights. One of those little
night-lights with a sensing photocell detects the light and cuts back
the charger.
--
"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 ---
I will not be using this address any more, and I would like to unsubscribe.
What is the procedure?
--- End Message ---
--- Begin Message ---
seth wrote:
No, series/paralel in the same motor. Solectria had it in their BRLS
line of motors as well. I used it personally. I don't think the
controller was smart enough to require knowing if it was in series mode
or parallel mode. Basically got you 2 different voltage and torque
constants for the motor. A nice thing considering the state of MOSFET
design circa 1991.
Seth
This is very doable and is known as "star-delta" switching rather
than "series-parallel". The big difference is we're talking
about the same physical motor, while as I understand ongoing
discussion, it is about connecting two independent series
wound DC motors to a single controller - first both motors
in series with each other and to the controller, and then in
parallel to each other and to the controller (while field and
armature are remain in series for each motor).
Totally different discussion vs single motor with switchable
windings option which can be arranged but not being discussed.
--
Victor
'91 ACRX - something different
--- End Message ---
--- Begin Message ---
Andre Blanchard wrote:
The whole point of using AC motors is to be high tech and have real nice
regen.
Sorry, it is far from reality. Else millions of the motors
in machine industry (lathe, fans, conveyors, etc etc) would
all use DC motors, and they are not.
High voltage takes more expensive silicon in both the speed control
and the charging system, and lets not forget fuses, contactors, and
connectors.
Being AC has nothing to do with being high voltage.
EV systems are high voltage to take advantage of lower
currents and relieve the stress from the batteries.
Low voltage EV inverters are produced by OEMs as well,
see 96V OEM example http://www.austinev.org/evalbum/160.html
it uses 65V...130V version of Simovert inverters.
Regarding fuses and contactors high current ones are just
as much more expensive compare to low current ones as
high voltage ones compare to low voltage ones.
Regarding chargers, if you take a line of the same model
like BRUSA NLG51x series, the cost varies only per watt;
130VDC...260VDC charger cost the same as 360VDC...720VDC one.
Bucking high voltage down for high current slow speed operation
takes fast expensive silicon. Being high tech is not the only or always the
best solution to a problem but it is what seems to attract the most
attention. I am not saying that AC is not a good way to go just that AC
does not need to mean high voltage.
What attracts most attention (other than regen) is lack of brushes,
high RPM allowing single gear reduction, easy electric reverse and
flat torque curve allowing the same acceleration on a freeway as on
the parking lot.
"High tech" is only a consequence of not being so well known and wide
spread. Working on it...
--
Victor
'91 ACRX - something different
--- End Message ---
--- Begin Message ---
Nope, it wasn't delta/wye or star/delta. It was series parallel. Been
there, done both.
Seth
Victor Tikhonov wrote:
>
> seth wrote:
>
> > No, series/paralel in the same motor. Solectria had it in their BRLS
> > line of motors as well. I used it personally. I don't think the
> > controller was smart enough to require knowing if it was in series mode
> > or parallel mode. Basically got you 2 different voltage and torque
> > constants for the motor. A nice thing considering the state of MOSFET
> > design circa 1991.
> >
> > Seth
>
> This is very doable and is known as "star-delta" switching rather
> than "series-parallel". The big difference is we're talking
> about the same physical motor, while as I understand ongoing
> discussion, it is about connecting two independent series
> wound DC motors to a single controller - first both motors
> in series with each other and to the controller, and then in
> parallel to each other and to the controller (while field and
> armature are remain in series for each motor).
>
> Totally different discussion vs single motor with switchable
> windings option which can be arranged but not being discussed.
>
> --
> Victor
> '91 ACRX - something different
--- End Message ---
--- Begin Message ---
> Subject: Re: one, or more, motors
>
> Aaron Birenboim wrote:
>
>
>> Do any available AC systems have series/parallel
>> switching available? (Zilla is DC...)
>>
>> Just dreaming....
When using AC induction motors you can switch the number of
poles. It just means rewiring the way the field coils are
energized. Going from say 4 poles to 2 poles would half the
torque, and double the speed, kind of like shifting a
transmission from low to high.
Jim Phillips
AC garden tractor
--- End Message ---
--- Begin Message ---
ThanX for the reply, but does anyone know of an
existing product that will drive an "IMA Type" Motor?
I've found the Curtis 1238 (80vdc 550A) 44kW!
" Tunable to any AC motor. "
Someone pointed out that:
"Insight uses a 3-pole brushless DC motor, not a 3-phase AC motor..."
"subtle but important difference there."
http://www.insightcentral.net/encyclopedia/enmotor.html
http://www.insightcentral.net/encyclopedia/enmdm.html
Others say it's a 3-Phase AC, as I thought? So Which is it?
Victor Tikhonov wrote:
Insight's IMA will not handle 10 kW for too long - it is not meant
for continuous duty and thus does not have adequate cooling.
I have performed continuous discharges (over mountain passes) which
subjected the IMA Motor to more than 5 minutes worth of full assist.
All, I'm looking for is a 5-15 second burst at 3 to 7 times
the semi-continuous 10kW normil assist rate.
Also control has to give pulsating current for IMA to
counter-react ICE vibration (as done in stock Insight).
Just running on smooth 3 phases will shake whole unit
a lot.
Yes, the IMA does all sorts of wonderfull things, but I've
opperated the car for extendid periods with the IMA disabled. I
wouldn't exactly call the Insight ICE "Rough" without IMA smoothing.
The things that I DO worry about is breaking 70A of current when
transitioning from Full IMA Assist to External IMA Assist Modes.
The Stock Controler will have it's motor abruptly removed from
it's circuit just as it's reaching Full Assist. The External
Controler would be turned off for the "Contactor Trade-Off".
But I'm not sure how the Stock controller will deal with loosing
and then re-aquiring it's inductor (motor) durring opperation.
I'm also a little worried about melting the IMA. (Grin)
L8r
Ryan
--- End Message ---
--- Begin Message ---
On Monday, April 19, 2004 2:12 PM, Jeff Shanab
[SMTP:[EMAIL PROTECTED] wrote:
> I have the base formula's to build up from scratch but I would need
> to know the wire,turns,insulation,laminate and mechanical data.
You have equations that go into that low-level of detail?
I think that if you work them a bit you will find that the
construction specific details like that condense into a couple of
simple motor constants (which of course may not remain constant when
your model tries to capture behaviour under normal as well as drag
racing conditions) that you can derive for each motor of interest
given some good test data.
Unfortunately, at the present time I don't think you will find it
easy (if even possible) to find test data for race conditions, so it
will be very difficult to develop equations which accurately model
race behaviour. Stay tuned though, as Rich Rudman may just become
the premier source of EV motor dyno data...
Its an ambitious undertaking; good luck!
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
I have heard the term 'rail' several times and I don't know what it
is, could you tell me?
[EMAIL PROTECTED] wrote:
No one has tried twin small motors in a rail with a Zilla
2000. The math says it should be quicker... Much quicker.
A rail is a type of drag race car, usually very long and narrow.
Dennis Berube's car is a rail, you can see it here:
http://www.CurrentEliminator.net/
hth.
--
-Otmar-
http://www.evcl.com/914 My electric 914
http://www.CafeElectric.com/ Zilla controllers in production, see them here.
--- End Message ---
--- Begin Message ---
Martin Klingensmith wrote:
I have heard the term 'rail' several times and I don't know what it
is, could you tell me?
A rail is one of those dragsters that seems to be all roll cage. Its
body is a bunch of rails, with wheels attached.
Very light. High power:weight ratio.
Judebert
--- End Message ---
--- Begin Message ---
I do not understand the need to series/parallel switch the field coils to
get field reduction on a series motor. This requires high voltage
contactors, breaking the field coil circuit in the middle, and more wire
exiting the motor case. Why not just bypass the entire field coil with a
low voltage relay and a little wire (sized to bypass the correct amount of
current)? The field coil only creates magnetic flux. Bypassing will also
reduce the resistance of the field circuit and allow more voltage to the
armature. Since voltage across the series coil is so low (< 1 volt) a cheap
golf cart contactor can do the job, even in a high voltage EV. Use a second
contactor with a longer length of wire to get three levels of field bypass:
level 1: longer wire in parallel with field
level 2: short wire in parallel with field
level 3: long and short wire all in parallel with field
This can be done on any motor with external field connections, as long as
brush advance or interpoles are there to take care of any commutation
problems.
Please let me know if I am missing something. Thanks, Mark T.
> Why limit the conversation to just two small motors and series/parallel
> switch verses one big motor. :)
>
> How about one big motor with series/parallel switching on the field coils.
> You could have two switch points, start with all four coils in series,
> switch to a parallel connection of two series coils, and last to all four
in
> parallel.
> You would likely need custom wound coils, bigger wire so that each coil
can
> handle full current. And maybe a larger case so there is room.
>
............................
> Thanks,
> Andre' B. Clear Lake Wis.
--- End Message ---
--- Begin Message ---
Mark Thomasson wrote:
> I do not understand the need to series/parallel switch the field
> coils to get field reduction on a series motor.
It's not so much a "need", but rather an option that can produce useful
benefits.
If you want to *weaken* the field, then the easiest route (as you said)
is to shunt it with a resistor. Field power is tiny compared to armature
power, so the energy lost in this resistor is not significant.
However, you can't use a PWM controller to drive a series motor with its
field shunted. The PWM controller depends on the field inductance. The
shunt shorts out this inductance, and the controller's current limit
won't work right.
So, you can rig things so the controller is always fully on or bypassed
when you field-weaken the motor. Or, you can rewire the field coils in
parallel pairs (instead of series). This weakens the field but *keeps*
most of the inductance.
The other opportunity in field switching is to *strengthen* the field.
Some motors already have pairs of field windings in parallel. Switching
them all in series will increase field strength, which lowers rpm but
raises torque.
--
"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 ---
Andre Blanchard wrote:
>> If you did a series/parallel switch on the windings in the AC
>> motor it should have the same effect it does on a DC system.
Yes, it does; but they have usually designed the inverter so it isn't
necessary.
Victor Tikhonov wrote:
> In short, you cannot do that, because at least:
> 1. the frequency in general is different for both motors.
Suppose you have a separate motor to drive each wheel. How much do you
think the speed will differ when turning the sharpest corner? Not much.
If they are induction motors, normal slip will be enough to handle it.
If driven with a single inverter, it will just behave like a car with a
limited-slip differential.
But if you are using PM motors (or trying for the ultimate in traction
control or efficiency), then you will want separate inverters so each
one can be independently micro-controlled to exactly the torque and
speed you want.
> 2. Stator windings are connected in a star or delta configuration,
> there is no "start" AND end of the same winding available.
> This may be arranged, but the reason 1 still applies.
It depends on the motor. There are always pairs of windings, one on each
side of the motor. They may be connected in series or parallel, as the
designer chooses. In some cases it is easy to change (they brought out
all the wires); in others, nearly impossible (they buried all the
connections inside, and only brought out 3 wires).
> The whole point of using AC motors and high enough voltage is
> to *avoid* all this series-parallel stuff being debated today.
There are *lots* of ways to solve every problem. AC drives just happen
to favor having a high voltage battery pack, so they can get lots of HP
at high rpm. But this means the controller must step down the voltage *a
lot* for low-speed operation.
DC drives just happen to favor having a low voltage battery pack, so the
controller doesn't need to step the voltage down as far for low-speed
operation. But the consequence is that you 'run out of voltage' at high
speeds.
In both cases (AC or DC), you can either switch the pack voltage or
motor windings in series/parallel to optimize them for high-speed or
low-speed operation. This is easier with DC motors, because there are
fewer windings to switch. It is also easier with DC controllers because
they are generally much simpler, and don't care about the motor's
parameters (nothing in the controller needs to change when the motor
windings are switched between series/parallel).
--
"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 ---
That would be great Martin, thanks. David Chapman.
----- Original Message -----
From: "Martin Klingensmith" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, April 19, 2004 8:28 AM
Subject: Re: Beefing up contactors
> I know several ceramic engineers if you would like me to ask for you.
>
> --
> --
> Martin Klingensmith
> http://infoarchive.net/
> http://nnytech.net/
>
> David Chapman wrote:
>
> >>
> >> Thanks Mark and Lee,
> >> Appreciate all the backround tech and suggestions. One last question
> on this
> >> tho, what do you think is the best mechanical solid state insulator if
> >> brittleness is not an issue? Glass? That was my best guess. Regards,
> David
> >> Chapman.
>
> Lee Hart wrote:
>
> > I'd probably use a ceramic. It won't burn or melt, and is a lot less
> > likely to break than glass. But there are a zillion of them; you'd have
> > to ask an application engineer at a ceramics manufacturer for some
> > ideas.
> >
> > The main reason I can see to shove something between the contacts is for
> > something like an emergency disconnect switch. It doesn't operate often,
> > but you want to be VERY sure it works when you *do* need it.
>
--- End Message ---
--- Begin Message ---
I'm just passing this on, hopefully we can get
more battery EV's involved.
Rod
Hi Everyone!
I want to let you all know about an important event
that needs
everyone's support:
Actor Dennis Weaver's International Hydrogen Drive
2004 (which will
include both hydrogen fuel cell and internal
combustion, hybrid and
bio-diesel vehicles) is confirmed!! This is a very
important cause
that is involving celebrities and politicians, but it
needs more
visibility among the actual environmental groups!
The link is http://www.hydrogendrive.com
The IHD2004 is an international caravan (with major
stars and
national political figures) -- all driving new
alternative fuel
vehicles to bring visibility to the progress
manufacturers have made
and the viability of these alternative vehicles. Both
celebrities
and politicians are signing up to become involved.
It will start in LA on June 28th, wind down to Mexico,
then back up
through California, Oregon, Washington, finally
finishing up in
Vancouver on July 12th. MSNBC will be covering it and
there will be
26 celebrity rallies, along the way! (As well as
future caravans to
be scheduled for other parts of the country, coming
soon!).
Here are the reasons I'm asking everyone to check out
IHD2004:
1. IHD2004 is an important kickoff for the
Geo-Political-
Environmentalism (G-P-E) movement -- which is
publicizing the
philosophy that we will never truly be safe until we
have no further
dependence on resources from the Middle East (i.e. no
more need for
oil).
2. IHD2004 will be bringing visibility to the fact
that the new
alternative fuel cars now include all shapes and sizes
and sources of
fuels and that many states are now setting up hydrogen
highways
(alternative fueling stations every 20 miles, along
their own main
highways, so people can fill up, as they go)!
3. My involvement: In addition to being a strong
supporter of
alternative fuels, I am also a TV/Film composer (in my
day job :o)
The International Hydrogen Drive is using my music (
http://janetritz.com/songs.htm ) for their theme song
and, frankly,
I'm hoping it will encourage people to check out more
of my music and
spread the word (as I make my living on cd sales).
Anyway, if you're
curious, please check out both
http://www.JanetRitz.com and the
Highlights box at http://hydrogendrive.com .
4. These drives have FREE celebrity rallies, along the
way, and are a
super way to have FUN and meet great people!
Please check out the above links, tell everyone you
know about
IHD2004, also please check out my music site
(http://www.janetritz.com) and forward this email to
all interested
parties!!
Thanks!
Janet Ritz
http://www.janetritz.com
http://www.hydrogendrive.com
--- End Message ---
--- Begin Message ---
Victor Tikhonov wrote:
Aaron Birenboim wrote:
It sure seems elegant to me if we can get rid
of the clutch/transmission/differentials for some
sort of simple reduction gear or belt to
drive shafts.
http://www.metricmind.com/images/mot4.jpg
http://www.metricmind.com/images/mot2.jpg
that mot4 looks pretty short. Perhaps you could get them
in back-to-back.
What about a V configuration? Since they have the output
shaft offset from the motor perhaps we could mount
the output shafts back-to-back, nice and symetric,
but have the main motors sitting next to each
other in kind of a V shape. i.e. The right wheel motor
tilted toward the front of the car, the left wheel motor
tilted toward the rear... but the drive shafts (mostly)
co-linear across the car.
Do any available AC systems have series/parallel switching
available? (Zilla is DC...)
Just dreaming....
Huh? 3 phase in series with what? How about sync with other
3 phases?...
I would think that for AC it would have to be a dual-controller.
Split the pack voltage between two inverters most of the
time. Put the dual controllers in parallel when
you need high power.
How does that dual-motor bus system work?
--
Aaron Birenboim | This space available!
Albuquerque, NM |
aaron_at_birenboim.com |
>http://aaron.boim.com |
--- End Message ---
--- Begin Message ---
Gee:
I'd just love to get my picture taken with a CELEBRITY mouthing some
easy to digest press release about the beauty of hydrogen. Then we
could all drive about half as far as a Tzero before that big truck
behind us would fill us up with the "most abundant element in the
universe" (and hardest to store) and off we'd go again. Meanwhile,
things are busy back at the 'ol power plant 'cause they were planning
on electric cars and now have to make 4 times as much juice for those
little Hindenbergs.
But alas, I'll have to miss all the fun and photos --- someone's got to
support the subsidies.
/Bob the clod
On Tuesday, April 20, 2004, at 06:33 AM, Rod Hower wrote:
I'm just passing this on, hopefully we can get
more battery EV's involved.
Rod
Hi Everyone!
I want to let you all know about an important event
that needs
everyone's support:
Actor Dennis Weaver's International Hydrogen Drive
2004 (which will
include both hydrogen fuel cell and internal
combustion, hybrid and
bio-diesel vehicles) is confirmed!! This is a very
important cause
that is involving celebrities and politicians, but it
needs more
visibility among the actual environmental groups!
The link is http://www.hydrogendrive.com
The IHD2004 is an international caravan (with major
stars and
national political figures) -- all driving new
alternative fuel
vehicles to bring visibility to the progress
manufacturers have made
and the viability of these alternative vehicles. Both
celebrities
and politicians are signing up to become involved.
It will start in LA on June 28th, wind down to Mexico,
then back up
through California, Oregon, Washington, finally
finishing up in
Vancouver on July 12th. MSNBC will be covering it and
there will be
26 celebrity rallies, along the way! (As well as
future caravans to
be scheduled for other parts of the country, coming
soon!).
Here are the reasons I'm asking everyone to check out
IHD2004:
1. IHD2004 is an important kickoff for the
Geo-Political-
Environmentalism (G-P-E) movement -- which is
publicizing the
philosophy that we will never truly be safe until we
have no further
dependence on resources from the Middle East (i.e. no
more need for
oil).
2. IHD2004 will be bringing visibility to the fact
that the new
alternative fuel cars now include all shapes and sizes
and sources of
fuels and that many states are now setting up hydrogen
highways
(alternative fueling stations every 20 miles, along
their own main
highways, so people can fill up, as they go)!
3. My involvement: In addition to being a strong
supporter of
alternative fuels, I am also a TV/Film composer (in my
day job :o)
The International Hydrogen Drive is using my music (
http://janetritz.com/songs.htm ) for their theme song
and, frankly,
I'm hoping it will encourage people to check out more
of my music and
spread the word (as I make my living on cd sales).
Anyway, if you're
curious, please check out both
http://www.JanetRitz.com and the
Highlights box at http://hydrogendrive.com .
4. These drives have FREE celebrity rallies, along the
way, and are a
super way to have FUN and meet great people!
Please check out the above links, tell everyone you
know about
IHD2004, also please check out my music site
(http://www.janetritz.com) and forward this email to
all interested
parties!!
Thanks!
Janet Ritz
http://www.janetritz.com
http://www.hydrogendrive.com
--- End Message ---
