EV Digest 4456
Topics covered in this issue include:
1) EV build training
by [EMAIL PROTECTED]
2) Antique hybrid idea
by Lee Hart <[EMAIL PROTECTED]>
3) RE: Contactor Voltage Ratings
by "Bill Dennis" <[EMAIL PROTECTED]>
4) Re: Contactor Voltage Ratings
by Lee Hart <[EMAIL PROTECTED]>
5) RE: Antique hybrid idea
by "Stu or Jan" <[EMAIL PROTECTED]>
6) Club Car 48V motor resistance
by Rod Hower <[EMAIL PROTECTED]>
7) Re: Antique hybrid idea
by Martin K <[EMAIL PROTECTED]>
8) Curtis control
by Rod Hower <[EMAIL PROTECTED]>
9) Balancing, was: Re: worn shafts journals, an' Stuff.
by James Massey <[EMAIL PROTECTED]>
10) Re: Curtis control
by Otmar <[EMAIL PROTECTED]>
11) Re: Club Car 48V motor resistance
by Otmar <[EMAIL PROTECTED]>
12) Re: Antique hybrid idea
by Neon John <[EMAIL PROTECTED]>
13) Modern hybrids, Re: Antique hybrid idea
by jerry dycus <[EMAIL PROTECTED]>
14) Re: My Blog is now up! Take a look!
by "Mark Ward" <[EMAIL PROTECTED]>
15) Re: Antique hybrid idea
by Lee Hart <[EMAIL PROTECTED]>
16) Re: Club Car 48V motor resistance
by Rod Hower <[EMAIL PROTECTED]>
17) Re: worn shafts journals, an' Stuff.
by "David Chapman" <[EMAIL PROTECTED]>
18) Re: Brake Beefup Question
by "David Chapman" <[EMAIL PROTECTED]>
19) Re: Contactor Voltage Ratings
by "David Chapman" <[EMAIL PROTECTED]>
20) Re: Contactor Voltage Ratings
by "Dave" <[EMAIL PROTECTED]>
21) Vas: reduction gear
by Seppo Lindborg <[EMAIL PROTECTED]>
22) Re: Taper Lock Specs? Anyone?
by Lee Hart <[EMAIL PROTECTED]>
23) Re: Brake Beefup Question
by "Philip Marino" <[EMAIL PROTECTED]>
24) EAA Club meeting Cookout, Invite.
by "Bob Rice" <[EMAIL PROTECTED]>
25) Re: worn Rabbits, an' Stuff.
by "Bob Rice" <[EMAIL PROTECTED]>
--- Begin Message ---
Hi, I'd like to get a few to several days of EV building/designing training
or attend a related conference. My focus is passenger vehicle conversions, AC
and/or DC. I'd like to obtain CEUs for such training/education. Thanks for
any direction.
I've heard of Mid-Del in Oklahoma City, OK.
Paul
--- End Message ---
--- Begin Message ---
I like old technology, and went to an antique engine show. They have
lots of antique cars, tractors, and engines of all sorts. Steam engines,
electric motors, diesels, and all sorts of odd gasoline engines from
days gone by.
The "hit-n-miss" or "dam-dam" engines were interesting. This is a
sort-of-normal small engine like you might find in a lawnmower. However,
they have an unusually large flywheel, and a valve mechanism that can be
disengaged. With the valves working, it runs like a normal engine. With
the valves off, it just freewheels -- the piston moves up and down, but
there are no pumping losses. The trapped air in the combustion chamber
just acts like a spring, returning the energy it takes for compression
on the downstroke.
The dam-dam engine is unique in that it always runs at full throttle.
The spark, timing, carburation, cam etc. are all optimized for
full-power only. Then they duty-cycle modulate it to get the actual
power desired. At "idle" it is actually spinning at full speed. It fires
once; and the freewheels for many seconds, fires again, freewheels many
seconds, etc. The sound it makes while doing this is is where the name
"hit-n-miss" or "dam-dam" comes from. Because of this mode of operation,
the part-load fuel economy is very good.
In practice, a governor senses flywheel speed, and engages the valve
train when it falls below a certain rpm; and disengages it above a
certain rpm. So engine rpm oscillates back and forth between these
speeds.
What caught my attention is that someone had one connected to a
generator, and used it as a battery charger. It looked like an old Ford
model A generator was coupled directly to the flywheel, and used its old
relay-type voltage regulator to control battery voltage and charging.
When there was no load on the battery, it charged at a couple amps, and
the dam-dam engine just fired once every 5 seconds or so. When he put a
load on the battery, the voltage sagged; the regulator called for more
current; the generator increased its load on the flywheel, and the
engine fired more and more often to maintain speed. A highly fuel
efficient hybrid power plant, built in the 1930's!
I wonder if this idea was ever used in a car? I wonder if it would be
practical today?
On the Prius (and most other normal cars), you get the best gas mileage
by "pulse mode" driving. This is how you win mileage contests. You
accellerate so the engine is at its peak efficiency point, which is
usually somewhere near full throttle. Then shut off the engine and let
the car coast down in speed. When it gets slow enough, restart the
engine and do it again. The Prius does this automatically, running on
batteries between times so you can actually maintain speed. On
conventional cars, you (and the drivers behind you :-) have to put up
with the constant speed-up and slow-down.
The dam-dam engine and a generator can do this, too. Ony they are doing
it at a far faster PWM frequency (many more on/off cycles per minute).
Thus, you shouldn't have the large speed changes during the cycle.
Any thoughts?
--
Ring the bells that you can ring
Forget your perfect offering
There is a crack in everything
That's how the light gets in
-- Leonard Cohen, from "Anthem"
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Thanks, Lee. I guess I'm still confused about "breaking the voltage."
Typically there's only a 40mV drop across the contactor. For example, if a
contactor is between the controller's M- and the battery minus, every time
the breaker opens, how is it "breaking 96 Volts?" How do 96 volts end up
across the contactor at that point?
Thanks.
Bill Dennis
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Lee Hart
Sent: Saturday, June 25, 2005 11:17 AM
To: [email protected]
Subject: Re: Contactor Voltage Ratings
Bill Dennis wrote:
> What's the story with the voltage ratings on contactors? For example,
> an SW200 is rated at a recommended 96V, yet people seem to use them
> for higher voltage packs all the time.
The ratings on a contactor (or switch, motor, fuse or other mechanical
device) are just one data point on a curve. The ratings on the SW200
contactor are telling you that *IF* you switch 96v at 250 amps, it will
typically last 100,000 cycles.
At lower voltages and currents, it lasts longer. At much lower voltages
and currents, it will typically last 1,000,000 cycles or more (called
the mechanical wear-out life).
Similarly, at higher voltages and currents, it still works but has a
shorter life. They give you one data point at high power; it will switch
96v at 1500 amps *once*! This is intended as an emergency cutoff, and
you would replace the contacts afterward.
Many EVers choose to use contactors (and switches, motors, and fuses) at
higher-than rated voltages to save money. They still work, but life is
reduced. At double the rated voltage, the device is still likely to
work, but life may be reduced 10:1 (to 10,000 cycles or less). Much
higher than 2:1, the device will probably fail to open at all -- it
won't be able to extinguish the arc on turn-off, and will burn itself up
trying.
> Also, would putting a contactor mid-pack make it need a smaller voltage
> rating?
No. It's a series circuit, so the voltage across it when open is the
same no matter where it goes. Same applies to fuses, circuit breakers
connectors, etc.
However, you can put multiple contacts in series to increase the voltage
rating. It is common to use *two* contactors in series, both operated
simultaneously, to double the voltage that they can safely break.
Likewise, it is common to have two or more connectors or switch contacts
in series for the same purpose.
--
Ring the bells that you can ring
Forget your perfect offering
There is a crack in everything
That's how the light gets in
-- Leonard Cohen, from "Anthem"
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Bill Dennis wrote:
>
> Thanks, Lee. I guess I'm still confused about "breaking the voltage."
> Typically there's only a 40mV drop across the contactor. For example, if a
> contactor is between the controller's M- and the battery minus, every time
> the breaker opens, how is it "breaking 96 Volts?" How do 96 volts end up
> across the contactor at that point?
Measure the voltage across the open contact; it will be the full pack
voltage. So, it goes from 40mv to full pack voltage; that's the voltage
it breaks.
However, the circuit affects this. If the controller happens to be off
at the time, then its capacitors stay charged for a while. The voltage
across the contactor's open contacts gradually rises from 40mv to pack
voltage as the capacitors discharge.
But if the controler is fully on when the contactor opens, then the
capacitors discharge almost instantly, and the contactor sees the full
pack voltage almost instantly. And, it has to break full motor current!
--
Ring the bells that you can ring
Forget your perfect offering
There is a crack in everything
That's how the light gets in
-- Leonard Cohen, from "Anthem"
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
I saw many of these engines running in a historical engine fair at Harpers
Ferry Virginia. What surprised me then is that when I asked about the fuel
economy of a guy with a saw mill, it was not very frugal with gas as I
recall. I assume that it was due to the poor machining and fit. BTW Many
engines had reservoirs of water cooling the engine heads. Just pour in
some when they got low.
Lee,
Have you thought about my inline:
engine>lockable freewheel>motor>clutch>transmission>differential setup?
I wonder whether a motor will start the engine in direct drive to the
engine?
BoyntonStu
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Lee Hart
Sent: Saturday, June 25, 2005 4:19 PM
To: EVlist - Electric Vehicle Discussion List
Subject: Antique hybrid idea
I like old technology, and went to an antique engine show. They have
lots of antique cars, tractors, and engines of all sorts. Steam engines,
electric motors, diesels, and all sorts of odd gasoline engines from
days gone by.
The "hit-n-miss" or "dam-dam" engines were interesting. This is a
sort-of-normal small engine like you might find in a lawnmower. However,
they have an unusually large flywheel, and a valve mechanism that can be
disengaged. With the valves working, it runs like a normal engine. With
the valves off, it just freewheels -- the piston moves up and down, but
there are no pumping losses. The trapped air in the combustion chamber
just acts like a spring, returning the energy it takes for compression
on the downstroke.
The dam-dam engine is unique in that it always runs at full throttle.
The spark, timing, carburation, cam etc. are all optimized for
full-power only. Then they duty-cycle modulate it to get the actual
power desired. At "idle" it is actually spinning at full speed. It fires
once; and the freewheels for many seconds, fires again, freewheels many
seconds, etc. The sound it makes while doing this is is where the name
"hit-n-miss" or "dam-dam" comes from. Because of this mode of operation,
the part-load fuel economy is very good.
In practice, a governor senses flywheel speed, and engages the valve
train when it falls below a certain rpm; and disengages it above a
certain rpm. So engine rpm oscillates back and forth between these
speeds.
What caught my attention is that someone had one connected to a
generator, and used it as a battery charger. It looked like an old Ford
model A generator was coupled directly to the flywheel, and used its old
relay-type voltage regulator to control battery voltage and charging.
When there was no load on the battery, it charged at a couple amps, and
the dam-dam engine just fired once every 5 seconds or so. When he put a
load on the battery, the voltage sagged; the regulator called for more
current; the generator increased its load on the flywheel, and the
engine fired more and more often to maintain speed. A highly fuel
efficient hybrid power plant, built in the 1930's!
I wonder if this idea was ever used in a car? I wonder if it would be
practical today?
On the Prius (and most other normal cars), you get the best gas mileage
by "pulse mode" driving. This is how you win mileage contests. You
accellerate so the engine is at its peak efficiency point, which is
usually somewhere near full throttle. Then shut off the engine and let
the car coast down in speed. When it gets slow enough, restart the
engine and do it again. The Prius does this automatically, running on
batteries between times so you can actually maintain speed. On
conventional cars, you (and the drivers behind you :-) have to put up
with the constant speed-up and slow-down.
The dam-dam engine and a generator can do this, too. Ony they are doing
it at a far faster PWM frequency (many more on/off cycles per minute).
Thus, you shouldn't have the large speed changes during the cycle.
Any thoughts?
--
Ring the bells that you can ring
Forget your perfect offering
There is a crack in everything
That's how the light gets in
-- Leonard Cohen, from "Anthem"
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Does anybody know the resistance of the series field
and armature of a 1995 Club Car series wound motor?
An approximate value would be fine.
Thanks,
Rod
--- End Message ---
--- Begin Message ---
Lee Hart wrote:
I like old technology, and went to an antique engine show. They have
lots of antique cars, tractors, and engines of all sorts. Steam engines,
electric motors, diesels, and all sorts of odd gasoline engines from
days gone by.
The "hit-n-miss" or "dam-dam" engines were interesting. This is a
sort-of-normal small engine like you might find in a lawnmower. However,
they have an unusually large flywheel, and a valve mechanism that can be
disengaged. With the valves working, it runs like a normal engine. With
the valves off, it just freewheels -- the piston moves up and down, but
there are no pumping losses. The trapped air in the combustion chamber
just acts like a spring, returning the energy it takes for compression
on the downstroke.
I've seen a 6ft flywheel version that ran on natural gas, used to pump
oil at the well. Sounded like a gun shot every few seconds. Weighed a
few tons, produced 10HP at a few hundred RPM max.
I wonder if this idea was ever used in a car? I wonder if it would be
practical today?
One would need to determine the benefit of doing such a thing. Is it
really better than varying the amount of A+F to change the speed of the
engine? Engineers have gotten very good at making IC engines about as
efficient as they can be, correct?
This is analogous to controlling an electric motor via voltage versus
power, isn't it? The hit-miss governs the engine based on speed
[voltage], where the normal IC engine is governed based on throttle [power].
The dam-dam engine and a generator can do this, too. Ony they are doing
it at a far faster PWM frequency (many more on/off cycles per minute).
Thus, you shouldn't have the large speed changes during the cycle.
Any thoughts?
I'm thinking that only an EE would use "hit-miss engine" and "pulse
width modulation" in the same paragraph :)
--
Martin K
http://wwia.org/
--- End Message ---
--- Begin Message ---
Schematic,
http://cafeelectric.com/curtis/curtisschematic.pdf
In the upper right of the schematic there is a diode
cathode connected to the drain of the power mosfets.
This is used for the DSAT current limit circuit.
Anybody know what type of diode this is?
It's kind of critical to the current limit circuit
(although I could use a pot to adjust the reference
voltage level).
There is also capacitive delay to allow the circuit to
turn on before current limiting, without guessing,
anybody know how long I should delay? (probably 5uSec,
but I would like other opinions).
Thanks,
Rod
--- End Message ---
--- Begin Message ---
At 10:49 AM 25/06/05 -0700, Jim Husted wrote:
<snip> When I look at how armatures are balanced they are balanced both
front and back, saying that it does matter where you balance to at least
some extent.
Hi all
We look after the equipment at our local dynamic balancers. They balance
blowers, fans, armatures, driveshafts, all sorts of ugly things. I asked
them about balancing my aramature and flywheel, for 6000RPM. They don't
actually balance above 3000, but they balance to a higher degree of
accuracy for higher RPMs. The item to be balanced is run between two sensor
assemblies, giving the balance condition at each end.
If an item is only static balanced, ie: put on a pair of knife edges, etc
and balanced until it doesn't roll, it may still vibrate. I'll try and
illustrate:
line 1 is the center of static balance, line 2 is the centerline of mass,
shown up by dynamic balancing.
Illustration 1, the center of mass is in the middle of the item, and
equally distant from centerline of rotation (at least it would be if ASCII
drawing would alow it). So the centerline of static balance is common to
the center of rotation and dynamic balance.
________
| mass |
| |
| |
___| |___
1,2--___| |___---1,2
| |
| |
| |
|__mass__|
Illustration 2, the center of mass is unequally offset from the middle of
the item, but equally distant from centerline of rotation (at least it
would be if ASCII drawing would alow it). So although the centerline of
static balance is common to the center of rotation, it is NOT common to the
center of dynamic balance, so at speed the item would still vibrate.
2
________ /
|mass |/
| |
| |
___| |___
1--___| |___---1
| |
| |
| |
/|____mass|
/
2
This is why driveshafts should always be dynamically balanced, as a static
balance will not guarantee no vibration. A statically balanced tailshaft
can be vibrating in one direction at the gearbox end, and the opposite
direction at the diff' end.
Question for John Wayland: Was the old driveshaft in White Zombie (the one
you had vibration problems with) static or dynamic balanced?
Hope this helps.
James
--- End Message ---
--- Begin Message ---
Schematic,
http://cafeelectric.com/curtis/curtisschematic.pdf
In the upper right of the schematic there is a diode
cathode connected to the drain of the power mosfets.
This is used for the DSAT current limit circuit.
Anybody know what type of diode this is?
It's kind of critical to the current limit circuit
(although I could use a pot to adjust the reference
voltage level).
There is also capacitive delay to allow the circuit to
turn on before current limiting, without guessing,
anybody know how long I should delay? (probably 5uSec,
but I would like other opinions).
Thanks,
Rod
Hi Rod,
IIRC the diode is a 200V signal diode. Not critical just so long as
it's not huge. (capacitance should be minimized) I use ERA34-10 from
Fuji, but that is probably overkill. Using another identical diode in
the reference circuit can compensate for changes of the current limit
setting with temperature.
Curtis blanks the current limit about 6 uS, this is also why the "B"
versions had such a problem with low resistance motors and high
voltage packs. Because of the blanking the minimum duty cycle that
the current limit can request is about 10%.
I suggest blanking 3-5 uS and also allowing it to skip cycles if the
current is too high. Then you can run large motors and get funny
noises at low duty cycle. :-)
--
-Otmar-
http://www.CafeElectric.com/ Home of the Zilla.
http://www.evcl.com/914 My electric 914
--- End Message ---
--- Begin Message ---
Does anybody know the resistance of the series field
and armature of a 1995 Club Car series wound motor?
An approximate value would be fine.
A ADC A89 is probably similar. Here are my notes
from back when I worked with them:
Room Temp resistance of series motor:
Field .016 at 3 A
Arm .056 at 3A
hth,
--
-Otmar-
http://www.CafeElectric.com/ Home of the Zilla.
http://www.evcl.com/914 My electric 914
--- End Message ---
--- Begin Message ---
On Sat, 25 Jun 2005 17:09:16 -0400, Martin K
<[EMAIL PROTECTED]> wrote:
>I've seen a 6ft flywheel version that ran on natural gas, used to pump
>oil at the well. Sounded like a gun shot every few seconds. Weighed a
>few tons, produced 10HP at a few hundred RPM max.
>
>> I wonder if this idea was ever used in a car? I wonder if it would be
>> practical today?
Here are a bunch of photos from the Florida Flywheelers who meet at
the Daytona Turkey Rod Run every year.
http://www.johngsbbq.com/Neon_John_site/RV/Trips/Daytona_Turkey_Run_2000/index3.html
http://www.johngsbbq.com/Neon_John_site/RV/Trips/Daytona_Turkey_Run_2001/index4.html
http://www.johngsbbq.com/Neon_John_site/RV/Trips/Daytona_Turkey_Run_2003/index3.html
John
---
John De Armond
See my website for my current email address
http://www.johngsbbq.com
Cleveland, Occupied TN
--- End Message ---
--- Begin Message ---
Hi Lee and All,
--- Lee Hart <[EMAIL PROTECTED]> wrote:
>
> The dam-dam engine is unique in that it always runs
> at full throttle.
> The spark, timing, carburation, cam etc. are all
> optimized for
> full-power only. Then they duty-cycle modulate it to
> get the actual
> power desired. At "idle" it is actually spinning at
> full speed. It fires
> once; and the freewheels for many seconds, fires
> again, freewheels many
> seconds, etc. The sound it makes while doing this is
> is where the name
> "hit-n-miss" or "dam-dam" comes from. Because of
> this mode of operation,
> the part-load fuel economy is very good.
> I wonder if this idea was ever used in a car? I
> wonder if it would be
> practical today?
Somewhat as some engines now use cyl cut off to
lower fuel consumption but you still have all that
internal friction that can add up to 20hp in many cars
wheher it's moving or not, enough to drive a car on
flat ground to 60-75mph depending on the car. And that
doesn't include ascessories. This is a big part of why
ICE's only get 7% of the fuels energy to the road and
an EV gets 20%.
Now instead use a 20hp engine that only has 3hp of
friction because it is much smaller, 1/5-1/10th the
normal size and the saving is great. Also on a
gasoline motor running at full power, doesn't have
trottle loses.
>
> On the Prius (and most other normal cars), you get
> the best gas mileage
> by "pulse mode" driving. This is how you win mileage
> contests. You
> accellerate so the engine is at its peak efficiency
> point, which is
> usually somewhere near full throttle. Then shut off
> the engine and let
> the car coast down in speed. When it gets slow
> enough, restart the
> engine and do it again. The Prius does this
> automatically, running on
> batteries between times so you can actually maintain
> speed. On
> conventional cars, you (and the drivers behind you
> :-) have to put up
> with the constant speed-up and slow-down.
>
> Any thoughts?
By running full all the time whenever the gas
hybrid motor is needed, the eff is so much higher that
it isn't even worth directly hooking it to the
driveshaft if 90% eff gen/ e drive motor is used
saving much weight, complication and costs. This
allows greater flexability too.
It's this kind of hybrid that will be our future
with a 100hp EV drive and 20hp gen in a 2,000lbs car
that can easily get 100mpg if aero for long distance
with a 50 mile range batt pack for most driving.
Jerry Dycus
> --
> Ring the bells that you can ring
> Forget your perfect offering
> There is a crack in everything
> That's how the light gets in
> -- Leonard Cohen, from "Anthem"
> --
> Lee A. Hart, 814 8th Ave N, Sartell MN 56377,
> leeahart_at_earthlink.net
>
>
__________________________________
Yahoo! Mail Mobile
Take Yahoo! Mail with you! Check email on your mobile phone.
http://mobile.yahoo.com/learn/mail
--- End Message ---
--- Begin Message ---
----- Original Message -----
From: "Lee Hart" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Saturday, June 25, 2005 1:38 PM
Subject: Re: My Blog is now up! Take a look!
LOL :-)
Fortunately it is not that bad! A fellow teacher has a machine shop so we
don't have to go that primitive! ROF
I feel like totally understanding something and being able to do it myself
puts me "in control" so to speak. I am now learning all about taper lock,
morse tapers, etc. I also found a link that has good photos of a working
motor adapter a guy made himself.
Mark
To date my best offer on the machine work is about $900 and
requires shipping my transmission to CA.
Well, there are "Cheap John" methods, too.
>>We discussed them a few
months back on the EV list. Ways to use standard industrial couplers,
and do machining using your traction motor as your lathe.
--
--- End Message ---
--- Begin Message ---
Stu or Jan wrote:
> I saw many of these engines running in a historical engine fair at
> Harpers Ferry Virginia. What surprised me then is that when I asked
> about the fuel economy of a guy with a saw mill, it was not very
> frugal with gas as I recall. I assume that it was due to the poor
> machining and fit.
Most of these engines were built in the 1920-1940's. I'm told their fuel
economy was good (especially at part-throttle) as compared to other
engines of the day. But my moderns standards they were very crude,
low-compression designs (as were the conventional engines of the day).
> Have you thought about my inline:
> engine>lockable freewheel>motor>clutch>transmission>differential setup?
A little. This is kind of what the Honda Insight does.
> I wonder whether a motor will start the engine in direct drive to the
> engine?
With enough current it will! Especially one of these hit-n-miss engines,
which have compression release. Even a small electric motor could slowly
bring them up to speed. Then it starts when the valve gear is enabled.
Martin K. wrote:
> One would need to determine the benefit of doing such a thing.
Yes; of course. My starting point is that even normal ICEs get markedly
higher efficiency when operated in "pulse mode" (cycling back and forth
between full power and off). The hit-n-miss engine is specifically
designed for pulse mode to begin with.
> Engineers have gotten very good at making IC engines about as
> efficient as they can be, correct?
Yes, but they constrain themselves to engines that have a continuous
power output. They don't have any electric motors or other systems to
provide smooth, continuous power while the ICE is being pulsed.
This is analogous to controlling an electric motor via voltage versus
power, isn't it?
Not quite. It is analogous to knowing the peak efficiency point for the
motor, and then using the controller so the motor is either on at its
peak efficiency point, or off and coasting. While this works with
electric motors, it is less effective since they have a broader
efficiency peak than ICEs.
--
The two most common elements in the universe are hydrogen and stupidity.
-- Harlan Ellison
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
So, .072 gives 666Amps with no back EMF locked rotor.
I could almost go with no C/L on this motor
using my ramped control.
I'll probably go the safe route and use DSAT C/L so
I don't blow up the power stage.
More info on what I'm doing;
I've interfaced one of my BLDC controls from work to
the Cursit power stage (new software written for this
application so it's more like a series control). I
tested it at work and it had controlled PWM ramp up
for acceleration without C/L circuits. I was
concerned that I may blow something up if I didn't
incorporate C/L control. This may not be an issue
with this motor and a golf cart as a load, but I think
I'll go the safe route and throw in a C/L circuit. My
plan is to use a comparator that looks at the DSAT
voltage via the above mentioned diode. The reference
for the comparator will be a voltage that is adjusted
with a trim pot to change reference, ie current limit.
The reason I asked these questions is to minimize
testing since it will be difficult to adjust when it's
installed on the cart.
Thanks for all the responses.
--- Otmar <[EMAIL PROTECTED]> wrote:
> >Does anybody know the resistance of the series
> field
> >and armature of a 1995 Club Car series wound motor?
> >An approximate value would be fine.
>
> A ADC A89 is probably similar. Here are my notes
> from back when I worked with them:
> Room Temp resistance of series motor:
> Field .016 at 3 A
> Arm .056 at 3A
>
> hth,
> --
> -Otmar-
>
> http://www.CafeElectric.com/ Home of the Zilla.
> http://www.evcl.com/914 My electric 914
>
>
--- End Message ---
--- Begin Message ---
Gee Bob, I see rust free Rabbits around here fairly frequently :-). Maybe
you should get a hitch put on the Prius and take one home next Woodburn.
Seeya then.
David Chapman
Arizona Electropulsion / Fine-Junque
http://stores.ebay.com/theworldoffinejunque
----- Original Message -----
From: "Bob Rice" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Saturday, June 25, 2005 9:47 AM
Subject: Re: worn shafts journals, an' Stuff.
> Hi Jim;
>
> Thanks for the good points, and a rather belated welcome to the List.
> Great to see more people aboard. Especially guyz that are making EV's
> happen. I guess I'm gunna hafta break down and fix it right, like have the
> shaft welded or built back up to spec. and buy some decent bearings THEN
get
> the damn thing balanced including the clutch an' flywheel. I have hearsd
> guyz say that SOME cars, Rabbit? Have EVERYthing balanced at once engine
> crankshaft and all. So IF you tale the flywheel off and use it on
something
> else, a motor, ya are out of balance, already , cuz it isn't on the
> origional crankshaft?Do I make any sense?
>
> So If I were to take the armature WITH the clutch and flywheel, maybe
> without the disk, pressure plate assembled to be balanced as one unit?Can
a
> balance place handle that glunky a thing?" Yeah! I do it all the time" I
> hear ya thinking? I have had a vibration issue right along but not that
> obnoxious that I thought it would be a problem.Damn TIRES were most if it,
> would take them back to the balance guy to have them done AGAIN. Over 70
it
> was a problem.
>
> Gunna go through the front end, new wrack an' pinion and ball joints,
> struts all that fadarah, gret everything tight again.Got Rust--o-Matic
> issues, too. Gotta fix the rotten floor and rocker panels. Better yet;
find
> a clean new Rabbit. Dream on! They are all mulch here!VERY few twenty year
> old cars here.Not like PDX's rolling auto museum that we eastern guyz
marvel
> over when in town.
>
> Seeya at Woodburn?
>
> Bob....the guy that makes that pilgrimage EVery year!
> >
>
--- End Message ---
--- Begin Message ---
Philip, I think what was meant was that stainless braided lines don't
"balloon" as much under pressure as a composite rubber hose. I ran both on
my hillclimb car and the brakes were a tad stiffer with the stainless
braided hoses due to the teflon liner.
David Chapman
Arizona Electropulsion / Fine-Junque
http://stores.ebay.com/theworldoffinejunque
----- Original Message -----
From: "Philip Marino" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Thursday, June 23, 2005 10:02 AM
Subject: Re: Brake Beefup Question
> Changing the rear should have a noticible effect on reduced stopping
> distance in a panic stop.
> >
> >In a panic stop the front brakes handle up to 90 percent of the braking.
> >The body shifts, the rear
> >end lifts, and most the work is done up front. Your best bet would be to
> >find a way to beef up the
> >front. Larger diameter discs. Another simple, effective, but somewhat
> >pricey change would be to
> >use stainless braided brake lines in the front. They direct more of the
> >pedal pressure to the
> >piston for better braking.
> >
>
> Not true - the pressure at both ends of ( and anywhere along the length
of )
> the brake line is the same regardless of the material ( or stiffness) of
the
> brake line.
>
> If you have a deteriorated brake line, you should replace it. But,
you
> would still have the same pressure at the caliper and the same stopping
> force (for a given brake pedal force) as with a new, stainless braided
line.
>
> None of the pressure "leaks out" or is redirected somewhere else even if
you
> have a bulging line. The only possible loss of braking ability is if it a
> line bulges so much that the pedal hits the floor (and a line will
generally
> fail completely well before that happens).
>
>
> Phil
>
> _________________________________________________________________
> Don't just search. Find. Check out the new MSN Search!
> http://search.msn.click-url.com/go/onm00200636ave/direct/01/
>
--- End Message ---
--- Begin Message ---
Series?
David Chapman
Arizona Electropulsion / Fine-Junque
http://stores.ebay.com/theworldoffinejunque
----- Original Message -----
From: "Lee Hart" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Saturday, June 25, 2005 11:16 AM
Subject: Re: Contactor Voltage Ratings
>
> However, you can put multiple contacts in series to increase the voltage
> rating. It is common to use *two* contactors in series, both operated
> simultaneously, to double the voltage that they can safely break.
> Likewise, it is common to have two or more connectors or switch contacts
> in series for the same purpose.
--- End Message ---
--- Begin Message ---
So the two sets of contacts would open at exactly the same instant?
David C Wilker Jr.
USAF (RET)
"The Bush administration's priorities are "a little bit different now
and veterans aren't a priority,"
----- Original Message -----
From: "David Chapman" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Saturday, June 25, 2005 10:35 PM
Subject: Re: Contactor Voltage Ratings
Series?
David Chapman
Arizona Electropulsion / Fine-Junque
http://stores.ebay.com/theworldoffinejunque
----- Original Message -----
From: "Lee Hart" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Saturday, June 25, 2005 11:16 AM
Subject: Re: Contactor Voltage Ratings
However, you can put multiple contacts in series to increase the voltage
rating. It is common to use *two* contactors in series, both operated
simultaneously, to double the voltage that they can safely break.
Likewise, it is common to have two or more connectors or switch contacts
in series for the same purpose.
--- End Message ---
--- Begin Message ---
You can reduce the AC motor speed by building it with more poles. If you use a
four-pole motor instead of a two-pole one, you get half the max rpm.
But this makes the motor bigger and heavier (for the same power). If you are
ready to take the extra weight and cost of a transmission, why not take the
extra weight and cost of the four-pole motor instead?
I am not an expert here, so I don't know exactly what weight and cost
differencies we are talking about but this might be at least worth checking?
Seppo
>
> Lähettäjä: "Don Cameron" <[EMAIL PROTECTED]>
> Päivä: 25.06.2005 05:40
> Vastaanottaja: <[email protected]>
> Otsikko: reduction gear
>
> Using AC drives one does not really need a transmission, as long as the
> gearing is right. With a typical rear differential, the ratio is usually
> from 3.5 to 4.4. However if a motor were to directly drive a popular 4.11
> rear end using a common 23" tire diameter, the car would be sacrificing low
> end acceleration for top end speed. (e.g. at 8000 RPM, the car would be
> going 133mph) - this is a little too fast for typical street use. Even
> hunting around for aftermarket ring and pinions all I can find is a 5.1:1
>
> I have read various threads about two speed transmissions and such, as well
> as I have seen the 8.3:1 reduction gear/differentials about, but what I am
> looking for is a simple reduction gear box.
>
> Has anyone seen an "off the shelf" reduction gear box in that I can get a
> selection of gears (e.g. 2:1 or 1.75:1) that hopefully can handle 150hp???
>
> thanks
> Don
>
>
> Victoria, BC, Canada
>
> See the New Beetle EV Conversion Web Site at
> www.cameronsoftware.com/ev/
>
>
>
>
>
--- End Message ---
--- Begin Message ---
Mark Ward wrote:
> My thoughts were that the torque converter would act as a flywheel
Yes; but you don't need a flywheel in an EV. It's just dead weight.
> would keep the vehicle from jerking when it was put in motion.
The starting lurch some EVs have has nothing to do with the flywheel.
There are two possible causes.
One is to have a large ADC 9" motor on an older Curtis 1221B or 1231B
controller. In this case, the controller's current limit circuit doesn't
work so the motor has a minimum speed. It goes from zero to this minimum
speed almost instantly; thus the starting lurch. This problem won't
occur with the Curtis 1221C or 1231C controllers, or with any of the
other common controllers.
The other affects EVs with an automatic transmission. Something has to
provide hydraulic pressure for the transmission when the motor is
stopped. If you just let the input pump be spun by the traction motor,
you'll get a starting lurch when the motor is started because it takes a
second or two for the transmission's internal pump to produce enough
hydraulic pressure to shift the transmission into gear. This problem can
be fixed by using a separate small motor to drive the pump, or by
leaving the traction motor idling when stopped (like an ICE).
> I need to spin the transmission anyway at about 200 rpms to keep
> my power steering pump working off the opposite end of the motor.
If you run the power steering pump (and possibly alternator, brake
vacuum pump, air conditioner compressor, and other devices) all off the
traction motor with belts like an ICE, then the easy solution is to
leave the traction motor idling.
> The stock converter is a lockup type with a "sport" mode on the
> shift lever. Supposedly this improves performance. I suppose the
> switch could be forced on at all times by rewiring it accordingly
> if the converter stays stock.
I suspect that the "sport" mode just changes the shifting points, and
does not have any control over the torque converter's lockup. If your
converter can be locked up, then make sure this feature still works; it
will give you 10% or so more range.
--
Humanity is acquiring all the right technology for all the wrong
reasons.
-- R. Buckminster Fuller
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
From: "David Chapman" <[EMAIL PROTECTED]>
Reply-To: [email protected]
To: <[email protected]>
Subject: Re: Brake Beefup Question
Date: Sat, 25 Jun 2005 22:31:25 -0700
Philip, I think what was meant was that stainless braided lines don't
"balloon" as much under pressure as a composite rubber hose. I ran both on
my hillclimb car and the brakes were a tad stiffer with the stainless
braided hoses due to the teflon liner.
David Chapman
Arizona Electropulsion / Fine-Junque
http://stores.ebay.com/theworldoffinejunque
----- Original Message -----
From: "Philip Marino" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Thursday, June 23, 2005 10:02 AM
Subject: Re: Brake Beefup Question
David - I agree with you about steel lines resulting in a stiffer pedal.
What I didn't agree with was that steel lines "direct more of the pedal
pressure" to the calipers than composite lines. The brake line material
doesn't affect the final pressure (and stopping ability) - but obviously a
stiffer pedal may allow you to apply that pressure an instant soooner ( and
give you better brake feel, also). So, you might stop the car in a
slightly ( very slightly) shorter distance overall.
Phil
> Changing the rear should have a noticible effect on reduced stopping
> distance in a panic stop.
> >
> >In a panic stop the front brakes handle up to 90 percent of the
braking.
> >The body shifts, the rear
> >end lifts, and most the work is done up front. Your best bet would be
to
> >find a way to beef up the
> >front. Larger diameter discs. Another simple, effective, but somewhat
> >pricey change would be to
> >use stainless braided brake lines in the front. They direct more of the
> >pedal pressure to the
> >piston for better braking.
> >
>
> Not true - the pressure at both ends of ( and anywhere along the length
of )
> the brake line is the same regardless of the material ( or stiffness) of
the
> brake line.
>
> If you have a deteriorated brake line, you should replace it. But,
you
> would still have the same pressure at the caliper and the same stopping
> force (for a given brake pedal force) as with a new, stainless braided
line.
>
> None of the pressure "leaks out" or is redirected somewhere else even if
you
> have a bulging line. The only possible loss of braking ability is if it
a
> line bulges so much that the pedal hits the floor (and a line will
generally
> fail completely well before that happens).
>
>
> Phil
>
> _________________________________________________________________
> Don't just search. Find. Check out the new MSN Search!
> http://search.msn.click-url.com/go/onm00200636ave/direct/01/
>
_________________________________________________________________
Is your PC infected? Get a FREE online computer virus scan from McAfee®
Security. http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963
--- End Message ---
--- Begin Message ---
Hi EVerybody;
It's that time again. Our usual EAA second-Sat-of-each-month meeting at
my place in Killingworth CT. The usual, EV's as many as we can round up.
Burgers ,and the usual munchies. Open grill, whatEVer ya wanna bring. Sorta
gotten to be a summer tradition. Oh yeah! The date July 9th, I forgot THAT
last year<g>!
Seeya? before Woodburn?
Bob
--- End Message ---
--- Begin Message ---
----- Original Message -----
From: "David Chapman" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Sunday, June 26, 2005 1:27 AM
Subject: Re: worn shafts journals, an' Stuff.
> Gee Bob, I see rust free Rabbits around here fairly frequently :-). Maybe
> you should get a hitch put on the Prius and take one home next Woodburn.
> Seeya then.
> Hi Dave;
Yeah, they tell ya NOT to pull a trailer, with Prei, but NOTHING about
towing a car<G.! In all seriousness, would it ruin a Preus to tow stuff, if
you drove it reasonably? it would have to engine more than motor, I'm sure?
It has towed my Rabbit, dead ,home a few times with a rope. You sure can't
PUSH with those crappy Plastic "Bumpers" !Prius had to grunt to pull the
3100 lb Rabbit in the cold, 20 degrees and I had plum run out of juice! If
ya were to strip it out and tow as a glider it would pull pretty easy,
though.
Sidelight; after returning to CT after Power of DC I went to the store in
the Rabbit. Gees! it pulls badly to the right and the front tires are all
chewed up. Near as I can figgur I musta towed it through a front end
destroying pothole, as it was fine in MD, did drive it around H'town it was
fine. Haven't had time to tear the front end down and fix it, so the Prius
has been pinch hitting on the Work run. I HATE buying gas! EVen less than I
would use in a gas car.Park in my usual spot there see all that electrucity
going to waste in my usual outlet, just leaking away! Sigh!Ya mean it
doesn't just leak out, if nothing is plugged in?? I remenber reading James
Thurber, American humorist from the Victrola record era, a short story about
his Mom, not understanding technology clearly, aren't Moms wonderful?
? She would go around the house plugging things in, to stop that infernal
ELECTRICITY from dripping out all over the house. She admonished folks NOT
to drive around without gas, it fried the valves or something? Wind up
Victrolas, using neither gas or electricity was her worst fear.They must be
powered by some mystical force ,to be delt with fear and suspician. Thurber
is a great read! Victrola, Victrolas, for you younger folks ,was the Victor
,made long before it was RCA Victor, acustical, wind up, phonograph. Playing
records at 78 rpm, no home was complete without one in the model T and
electric car era, the first one.I still have alota the records, enjoy them
still. Victor TALKING Machine Co. Camden NJ. If yur record sez that, it is
older than 1929, when they merged with that Upstart Radio Corp of
America.....RCA. This doesn't apply to CD's though<G>!Another Co made it big
with car radios, a Motor-Rola, instead of a Victor-ola." Ola "was a catch
thing back then.OK, end of history stuff for now.
Seeya
Bob
--- End Message ---
