EV Digest 3405
Topics covered in this issue include:
1) Re: Siemens motors on ebay
by "David Roden" <[EMAIL PROTECTED]>
2) Re: 1958 MGA Conversion
by Ryan Bohm <[EMAIL PROTECTED]>
3) motor current limit?
by Ryan Bohm <[EMAIL PROTECTED]>
4) [SALE] 1997 Ranger 45K miles / partial conversion
by Dragan Stancevic <[EMAIL PROTECTED]>
5) Re: motor current limit?
by "Jack Knopf" <[EMAIL PROTECTED]>
6) Re: motor current limit?
by Rich Rudman <[EMAIL PROTECTED]>
7) Re: motor current limit?
by Lee Hart <[EMAIL PROTECTED]>
8) Re: motor current limit?
by "Jack Knopf" <[EMAIL PROTECTED]>
9) Re: Donor Car Recommendation
by Victor Tikhonov <[EMAIL PROTECTED]>
10) RE: Flaming wreckage...
by "Jamie Marshall \(GAMES\)" <[EMAIL PROTECTED]>
11) Re: motor current limit?
by "Chuck Hursch" <[EMAIL PROTECTED]>
12) Re: motor current limit?
by Peter VanDerWal <[EMAIL PROTECTED]>
13) Re: E-meter alternatives
by Victor Tikhonov <[EMAIL PROTECTED]>
14) RE: motor current limit?
by "Andre Blanchard" <[EMAIL PROTECTED]>
15) Re: Siemens motors on ebay
by Victor Tikhonov <[EMAIL PROTECTED]>
16) RE: motor current limit?
by "Andre Blanchard" <[EMAIL PROTECTED]>
17) RE: E-meter alternatives
by "Andre Blanchard" <[EMAIL PROTECTED]>
18) Re: motor current limit?
by Rich Rudman <[EMAIL PROTECTED]>
19) Re: motor current limit?
by Rich Rudman <[EMAIL PROTECTED]>
20) RE: motor current limit?
by Peter VanDerWal <[EMAIL PROTECTED]>
21) EV Trike Free To Good Home
by Electro Automotive <[EMAIL PROTECTED]>
22) Used 220V Charger for Sale
by Electro Automotive <[EMAIL PROTECTED]>
23) On-Road EV Inventory
by "Darryl McMahon" <[EMAIL PROTECTED]>
--- Begin Message ---
Does it seem to anyone else that the output shaft looks kind of indistinct
in the photo on the auction listing? Everything else in the pic looks nice
and sharp; you can even see the texture of the power cables. I just wonder
why that output shaft looks so blurry to me.
Must be my medieval (middle aged) eyes.
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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
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
The illegal we do immediately. The unconstitutional takes a
little longer.
-- Henry Kissinger
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
--- End Message ---
--- Begin Message ---
Some info. I have received on the Prestolite MTC-4001 from others on the
list:
"The Prestolite MTC4001 is a very tough motor. This is the motor
that Ed Rannberg ran at 192 volts in his 11 second "Kawashocki".
It was also used extensively by Jet Industries in the early 80s for the
conversion of new gliders to electric. I would highly recommend that you
run this motor at 120 volts. This is where it comes alive."
"That is a tough little motor. I have one in my EV buggy and another
powers the EV Rabbit Pickup I sold. The motor curves (up to 100v) are
posted at <http://www.austinev.org/evalbum/tech/> (toward the bottom of
the page). Continuous current is about 170 amps at around 4000rpm (at
least as much as an ADC 8 inch motor). These motors have nice large
brushes and can take alot of amps for a short length of time. I've been
told its safe to run up to at least 144 volts. Its my favorite motor.
At 110 volts (actual, 120v pack) the motor will draw about 400 amps at
about 3500rpm. So, this is about where my 400 amp controller comes out
of current limit. A higher amp controller would come out of current
limit at a lower rpm. Running at an even higher voltage will increase
the rpm where the motor comes out of current limit. The motors peak
efficiency is somewhat above this rpm, around 4000 (and variable,
depending on applied voltage and rpm)."
Hope this helps.
-Ryan
Diana Trevino wrote:
Nice car, I used to work in Fremont. That Prestolite 4001 , is that about
the same as the ADC 4001 which is 100 hp, 30 hp cont.? Have any close
pictures on where the batts are mounted ?
Jack,
Negative 48 L C
----- Original Message -----
From: "Grannes, Dean" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Wednesday, March 10, 2004 10:37 AM
Subject: RE: 1958 MGA Conversion
Jack,
I am the proud owner of a 1959 MGA conversion. See it at
http://www.austinev.org/evalbum/114.html
I didn't do the conversion myself. It was converted by the late EV
pioneer Bob Wing. I know a little of its history--it went through
several changes in configuration since its original conversion to
electric in 1972(!). Currently it has 20 Optimas, buddy-paired for
120V. It is garaged, but has been itching to get out on the road since
the weather turned warm this past weekend in the Bay Area.
I'd be happy to try to answer any questions you have either on- or
off-list. Alas, I don't know the weight of the vehicle.
Dean Grannes
1979 VW Rabbit "Blue Phantom"
1959 MGA "Fire Chief"
--- End Message ---
--- Begin Message ---
Can someone explain what a motor's current limit means, e.g.
"The motor comes out of current limit at about 3500 rpm"
What is a typical current limit for say an ADC 9"?
Thanks,
Ryan
--- End Message ---
--- Begin Message ---
This day comes with great sadness and I'm still very conflicted about this
sale.
I'm selling my partial conversion for more info go to:
http://www.xalien.org/ford/
Thanks.
--
Peace can only come as a natural consequence
of universal enlightenment. -Dr. Nikola Tesla
--- End Message ---
--- Begin Message ---
I thought current limit of a motor was when the studs start to melt?
----- Original Message -----
From: "Ryan Bohm" <[EMAIL PROTECTED]>
To: "Electric Vehicle Discussion List" <[EMAIL PROTECTED]>
Sent: Monday, March 15, 2004 9:05 AM
Subject: motor current limit?
> Can someone explain what a motor's current limit means, e.g.
>
> "The motor comes out of current limit at about 3500 rpm"
>
> What is a typical current limit for say an ADC 9"?
>
> Thanks,
>
> Ryan
>
--- End Message ---
--- Begin Message ---
Jack Knopf wrote:
>
> I thought current limit of a motor was when the studs start to melt?
> ----- Original Message -----
> From: "Ryan Bohm" <[EMAIL PROTECTED]>
> To: "Electric Vehicle Discussion List" <[EMAIL PROTECTED]>
> Sent: Monday, March 15, 2004 9:05 AM
> Subject: motor current limit?
>
> > Can someone explain what a motor's current limit means, e.g.
> >
> > "The motor comes out of current limit at about 3500 rpm"
> >
> > What is a typical current limit for say an ADC 9"?
> >
> > Thanks,
> >
> > Ryan
> >
HEY that's My line!!1 or Rod's if you like breaking stuff with Sucking
too many amps.
Motor current, Motor current is the current flowing in the motor
Pretty simple, pretty clear.
Now add a PWM solid state motor controller, with a LOT of freewheeling
diodes. This would be Zillas, and DCPs, and well yes Curtii, but with
less diodes.
Things get a bit harder to explain but it's this simple. You ask for
torque by standing on the throttle pot, this commands the controller to
increase the amps flowing in the motor, It lengthens the on part of the
PWM wave form, this lets more power flow from the batteries to the
motor. When the controller goes to the off part of the PWM wave the
current stops flowing from the batteries, and freewheels through the
controller's diodes. So you have short high current high voltage pulses
comming from the batteries, Once they are in the motor side of the
controller, the voltage spikes can't rise instantly becasue of the
inductance of the motor. So they raise the current but slowly raise the
voltage.
Or The big volts and low current get changed inside the controller to
Big amps and less voltage.
Why.... If you dumped the total battery voltage onto a stalled,or
stopped or heavily loaded motor, many thousands of amps would flow,
because the motor looks like a dead short at stalled speed. This is
contactor control, CHirp! ClanK! What broke? We want control. So most
of the time nothing near the total battery voltage is applied to the
motor, Even when you have many hundreds of amps flowing... the motor
voltage is always less than the battery voltage, so the motor current is
always higher that Batt current.
In testing, you get to see this...all the time, and with a dyno in my
shop, I got to play with it yesteday. I had 450 amps flowing in a
Advanced 8 incher, with only 43 motor volts across it, and about 2100
rpm. The most I saw in the battery loop was 180 amps and 88 volts. This
is a Batt:motor ratio of 2.5:1. If I load the motor down farther in RPM,
the ratio gets much higher. I saw 6:1 at one time. And lets also keep in
mind that amps is Torque. And by the way 450 amps is about 80 Ftlbs on
this motor. So all you Curtis
400 amper folks out there, Foot to the floor is about 75 ftlbs of torque
on the motor shaft.
So a 400 amp controller, that makes or allows 400 amps to flow in both
the motor side and the battery side, is nice, but not really agressive
enough for a lot of us.
Then we had the 400 battery amp and 680 motor amp controllers, Much
better lauching, but kinda booring on the high side. A healthy 400 amp
Curtii would eventually outrun a 680 amp Auburn. Because the Auburn had
a 380 amp battery limit. At the high end... this counts, and the low end
the 680 motor current counts big time.
Then we had the Raptor 1200s. They would(and still do!) allow 1200 amps
from the battery, and there was no limit on motor peak amps, just 1082
amps of diodes, that could be pushed to 5 times that for short burst.
The gamble was that almost nobody would ever get out there for long.
Wrong! A badly arcing motor does that quite often.
Welded diodes told that story! These controllers still own most of the
less than 200 volt racing classes. Very powerfull, Rugged, but not
indestructable.
Now we have the Zillas. They regulate the motor current and the battery
current. They have a handle on all the issues. And you can program the
limits of both seprately. These are just now becoming available in
reasonable volume.
Current limit on a AvDC 9??? there is none, just when it melts, arcs or
flys apart. Now what is prudent? This is a better question.
The motor does not come out of current limit, the controller does. And
Yes at 3500 rpm and 120 volts the 9incher won't draw much more than 400
amps So the controller See less than it's limits and goes wide open. Or
at this time the motor current and the battery current are the same.
Wide open at low voltage(For us racers!) In DCP controllers we turned on
a Yellow LED when this happened, so we would know that the controller
was "full on" at this time.
DCP and Zillas would come out of current limit alot sooner. Since they
have a LOT higher limits.
Well I would say that the 9" inchers can take well over 1000 amps and
might have some pretty good hang time at 2000 amps, if properly timed
for both the amps and RPM that the amps will happen at. A 400 amp
controller... won't hurt a 9, A 1200 amper might cook it in about 5
minutes, if it can keep itself cool. At about 1500 amps you have
seconds of run time before a cool down rest is needed. At 2000 amps, We
don't really know yet, but not very long at all. Say 10 to 15 seconds.
Oh yea I think Advanced DC says the peak amps for a 9 incher is like 750
amps.
Yea Riiiiiiiight!
--
Rich Rudman
Manzanita Micro
www.manzanitamicro.com
1-360-297-7383,Cell 1-360-620-6266
--- End Message ---
--- Begin Message ---
Ryan Bohm wrote:
>
> Can someone explain what a motor's current limit means, e.g.
>
> "The motor comes out of current limit at about 3500 rpm"
>
> What is a typical current limit for say an ADC 9"?
The current limit is set by the controller, not the motor. It is the
maximum current that the controller will deliver, regardless of the
motor. Here are a typical controller's specs (Curtis 1231C-86xx). Note
that as the controller heats up, its current limit falls.
voltage input: 96-144 volts
current limit: 500 amps max
500 amps after 2 minutes
375 amps after 5 minutes
225 amps after 1 hour
But, the current that the motor will *accept* varies with voltage and
rpm. So at any given moment, the actual motor current will be set by
either the controller or the motor, whichever is lower.
Here are the specs for a typical motor (Advanced DC L91-4003). Note that
the current it draws is determined by the torque it is producing.
current, amps 100 200 300 400 500 750
torque, ft.lbs. 10 24 40 60 84 150
When you start from a dead stop with this motor and a cold controller,
the initial current is a constant 500 amps, and the torque is a constant
84 ft.lbs. The controller and motor are in "current limit". The car
accellerates, and motor speed increases.
As the motor speeds up, its back emf (motor voltage) rises. At constant
current (controller in current limit), motor voltage is directly
proportional to rpm. Here is the data for the L91-4003 (at 500 amps).
speed, rpm 2250 2600 2850
motor voltage 75v 96v 120v
motor current 500a 500a 500a
Suppose you have a 96v pack. Then the motor will accellerate at 500 amps
and 84 ft.lbs. until it reaches 2600 rpm. At this speed, the controller
"comes out of current limit". As motor speed continues to increase, its
voltage can't rise any more (the controller is just connecting it
straight across the battery). So motor current falls, as does torque.
Current is now limited not by the controller, but by the motor itself.
So, here is the overall data for the L91-4003 with this controller and a
96v pack.
motor rpm 2250 2600 3000 4000 5000 6000
motor voltage 75v 96v 96v 96v 96v 96v
motor ft.lbs. 84 84 65 30 16 11
motor current 500a 500a 425a 240a 150a 100a
Below 3000 rpm, the controller is limiting motor current. Above 3000
rpm, the controller is full-on; the motor is limiting its own current.
--
"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 ---
Now that's some down to earth " Amps " talk. Now, "What If " someone had a
2000 amp, non-electronic, non-contactor controller. Out to the shop tonight!
----- Original Message -----
From: "Rich Rudman" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, March 15, 2004 12:02 PM
Subject: Re: motor current limit?
> Jack Knopf wrote:
> >
> > I thought current limit of a motor was when the studs start to melt?
> > ----- Original Message -----
> > From: "Ryan Bohm" <[EMAIL PROTECTED]>
> > To: "Electric Vehicle Discussion List" <[EMAIL PROTECTED]>
> > Sent: Monday, March 15, 2004 9:05 AM
> > Subject: motor current limit?
> >
> > > Can someone explain what a motor's current limit means, e.g.
> > >
> > > "The motor comes out of current limit at about 3500 rpm"
> > >
> > > What is a typical current limit for say an ADC 9"?
> > >
> > > Thanks,
> > >
> > > Ryan
> > >
>
>
> HEY that's My line!!1 or Rod's if you like breaking stuff with Sucking
> too many amps.
>
> Motor current, Motor current is the current flowing in the motor
> Pretty simple, pretty clear.
>
> Now add a PWM solid state motor controller, with a LOT of freewheeling
> diodes. This would be Zillas, and DCPs, and well yes Curtii, but with
> less diodes.
> Things get a bit harder to explain but it's this simple. You ask for
> torque by standing on the throttle pot, this commands the controller to
> increase the amps flowing in the motor, It lengthens the on part of the
> PWM wave form, this lets more power flow from the batteries to the
> motor. When the controller goes to the off part of the PWM wave the
> current stops flowing from the batteries, and freewheels through the
> controller's diodes. So you have short high current high voltage pulses
> comming from the batteries, Once they are in the motor side of the
> controller, the voltage spikes can't rise instantly becasue of the
> inductance of the motor. So they raise the current but slowly raise the
> voltage.
> Or The big volts and low current get changed inside the controller to
> Big amps and less voltage.
> Why.... If you dumped the total battery voltage onto a stalled,or
> stopped or heavily loaded motor, many thousands of amps would flow,
> because the motor looks like a dead short at stalled speed. This is
> contactor control, CHirp! ClanK! What broke? We want control. So most
> of the time nothing near the total battery voltage is applied to the
> motor, Even when you have many hundreds of amps flowing... the motor
> voltage is always less than the battery voltage, so the motor current is
> always higher that Batt current.
> In testing, you get to see this...all the time, and with a dyno in my
> shop, I got to play with it yesteday. I had 450 amps flowing in a
> Advanced 8 incher, with only 43 motor volts across it, and about 2100
> rpm. The most I saw in the battery loop was 180 amps and 88 volts. This
> is a Batt:motor ratio of 2.5:1. If I load the motor down farther in RPM,
> the ratio gets much higher. I saw 6:1 at one time. And lets also keep in
> mind that amps is Torque. And by the way 450 amps is about 80 Ftlbs on
> this motor. So all you Curtis
> 400 amper folks out there, Foot to the floor is about 75 ftlbs of torque
> on the motor shaft.
> So a 400 amp controller, that makes or allows 400 amps to flow in both
> the motor side and the battery side, is nice, but not really agressive
> enough for a lot of us.
> Then we had the 400 battery amp and 680 motor amp controllers, Much
> better lauching, but kinda booring on the high side. A healthy 400 amp
> Curtii would eventually outrun a 680 amp Auburn. Because the Auburn had
> a 380 amp battery limit. At the high end... this counts, and the low end
> the 680 motor current counts big time.
> Then we had the Raptor 1200s. They would(and still do!) allow 1200 amps
> from the battery, and there was no limit on motor peak amps, just 1082
> amps of diodes, that could be pushed to 5 times that for short burst.
> The gamble was that almost nobody would ever get out there for long.
> Wrong! A badly arcing motor does that quite often.
> Welded diodes told that story! These controllers still own most of the
> less than 200 volt racing classes. Very powerfull, Rugged, but not
> indestructable.
> Now we have the Zillas. They regulate the motor current and the battery
> current. They have a handle on all the issues. And you can program the
> limits of both seprately. These are just now becoming available in
> reasonable volume.
>
> Current limit on a AvDC 9??? there is none, just when it melts, arcs or
> flys apart. Now what is prudent? This is a better question.
> The motor does not come out of current limit, the controller does. And
> Yes at 3500 rpm and 120 volts the 9incher won't draw much more than 400
> amps So the controller See less than it's limits and goes wide open. Or
> at this time the motor current and the battery current are the same.
> Wide open at low voltage(For us racers!) In DCP controllers we turned on
> a Yellow LED when this happened, so we would know that the controller
> was "full on" at this time.
>
> DCP and Zillas would come out of current limit alot sooner. Since they
> have a LOT higher limits.
> Well I would say that the 9" inchers can take well over 1000 amps and
> might have some pretty good hang time at 2000 amps, if properly timed
> for both the amps and RPM that the amps will happen at. A 400 amp
> controller... won't hurt a 9, A 1200 amper might cook it in about 5
> minutes, if it can keep itself cool. At about 1500 amps you have
> seconds of run time before a cool down rest is needed. At 2000 amps, We
> don't really know yet, but not very long at all. Say 10 to 15 seconds.
> Oh yea I think Advanced DC says the peak amps for a 9 incher is like 750
> amps.
> Yea Riiiiiiiight!
>
> --
> Rich Rudman
> Manzanita Micro
> www.manzanitamicro.com
> 1-360-297-7383,Cell 1-360-620-6266
>
--- End Message ---
--- Begin Message ---
Dean Thompson wrote:
I am still hunting for my donor car. I want to use a small light, car
2dr hatchback with enough room for a 6'2" driver. Max 2 passengers. I
have been looking at Geo Metros, Fireflys and Swifts (1995 and better)
however the payload is not all that good. The Mazda 323 payload looks
better. Anybody have any other suggestions or recommendations?
Technically, IMHO for a 2 seater donor nothing beats Insight.
You may not like its styling, but you'll be hard pressed to
find more efficient and so well designed modern vehicle.
My 2 mm.
--
Victor
'91 ACRX - something different
--- End Message ---
--- Begin Message ---
Ever seen the 'exploding wire' trick? Charge up a big capacitor to a
couple hundred volts. Short it thru a small piece of wire. The wire goes
*KABOOM* just like a firecracker. It will also blow holes in things just
like a firecracker. (I do it with a 1000uF capacitor, mercury switch in
series with a few feet of #18 AC line cord, with just one strand
shorting the far end together. Charge up the capacitor to a few hundred
volts, tip it over so the mercury switch shorts, and BANG!)
Now, the fuse link inside a fuse is just such a little wire (you'd be
amazed at how small it is in a high-current fuse). The controller
provides just such a set of high-current capacitors. All you need is a
nice, solid short circuit. What do you think a firecracker going off
inside your fuse would do?
A friend of mine is a commercial electrician. He was just telling me
that the expansion ratio of copper sublimating (vaporizing) is close to
the same as the expansion ratio of exploding TNT. So the shockwave is
just as strong. (so vaporize a chunk of copper the size of a stick of
dynamite, and just as much force is produced)
Apparently much progress has been made in saftey requirements in the
last ten years or so to avoid shocking electricians. As a result of
this, shockwaves are becoming more prevelant in the cause of death of
electricians.
An example of this he gave me was that he is required to have
screwdrivers with some huge (I think it was 2000v) insulation rating to
work in a live panel of a certain kind. The idea is that anything that
croses the front plane of the panel must be insulated for that voltage.
So if he accidentally shorts two bus bars together, he won't get
shocked.
But how much metal is going to vaporize?
I found this morbidly fascinating.
-Jamie
--- End Message ---
--- Begin Message ---
Lee Hart wrote:
> Suppose you have a 96v pack. Then the motor will accellerate at
500 amps
> and 84 ft.lbs. until it reaches 2600 rpm. At this speed, the
controller
> "comes out of current limit". As motor speed continues to
increase, its
> voltage can't rise any more (the controller is just connecting
it
> straight across the battery). So motor current falls, as does
torque.
> Current is now limited not by the controller, but by the motor
itself.
> So, here is the overall data for the L91-4003 with this
controller and a
> 96v pack.
>
> motor rpm 2250 2600 3000 4000 5000 6000
> motor voltage 75v 96v 96v 96v 96v 96v
> motor ft.lbs. 84 84 65 30 16 11
> motor current 500a 500a 425a 240a 150a 100a
This is simplified somewhat in that it doesn't account for pack
voltage sag (which is dependent on the resistance in the battery
pack). With my 96V pack of US125 or Trojan T125 going up the
steep hill to my apt, if I'm in 1st gear and the pack is fairly
well charged up and healthy, I'll do about 17-18 mph with about
350-375A of motor (8" ADC) current. I think the Curtis
1231C-8601 (500A motor current limit) is at about 100% duty
cycle. When I was having a problem years ago with my 1221B on
this hill, I was taking measurements with a voltmeter (albeit
digital) before and after the controller, and found that the
voltage for both the motor and battery was about 79V. I think
the 1221B was almost at current limit, the 1231C has some
headroom (and lives to see year after year). So from what people
say, I'm out of current limit, and more or less connected
straight to the battery pack.
I've tried this hill once or twice in 2nd gear with the 1231C. I
can get a good head of speed on the small flat section of the
bottom, up to about 30mph using 2nd gear (and, hey, I'm speeding
at that point ;-> in the 25 zone). As I hit the wall-of-a-hill,
in a few seconds, the motor current goes up quickly as the car
slows down into the low 20s. I can't quite make the top of the
hill, and have to downshift (losing a significant chunk of
momentum) to 1st by the time I'm to 18mph or so.
Lee: why occasionally do your postings have gb2312 simplified
chinese character set asked for? I thought I had installed
simplified chinese (but maybe not that charset). My computer
points that out every once in awhile when I bring up one of your
postings (I'm not on web-mail, but using an email client on my
harddrive). Do you have a Chinese correspondent?
>
> Below 3000 rpm, the controller is limiting motor current. Above
3000
> rpm, the controller is full-on; the motor is limiting its own
current.
--- End Message ---
--- Begin Message ---
Now I'm confused.
What kind of controller doesn't use either contactors or electronics?
I suppose you could use a really big rheostat, but wouldn't that be
considered "electronics"?
On Mon, 2004-03-15 at 12:45, Jack Knopf wrote:
> Now that's some down to earth " Amps " talk. Now, "What If " someone had a
> 2000 amp, non-electronic, non-contactor controller. Out to the shop tonight!
> ----- Original Message -----
> From: "Rich Rudman" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Monday, March 15, 2004 12:02 PM
> Subject: Re: motor current limit?
>
>
> > Jack Knopf wrote:
> > >
> > > I thought current limit of a motor was when the studs start to melt?
> > > ----- Original Message -----
> > > From: "Ryan Bohm" <[EMAIL PROTECTED]>
> > > To: "Electric Vehicle Discussion List" <[EMAIL PROTECTED]>
> > > Sent: Monday, March 15, 2004 9:05 AM
> > > Subject: motor current limit?
> > >
> > > > Can someone explain what a motor's current limit means, e.g.
> > > >
> > > > "The motor comes out of current limit at about 3500 rpm"
> > > >
> > > > What is a typical current limit for say an ADC 9"?
> > > >
> > > > Thanks,
> > > >
> > > > Ryan
> > > >
> >
> >
> > HEY that's My line!!1 or Rod's if you like breaking stuff with Sucking
> > too many amps.
> >
> > Motor current, Motor current is the current flowing in the motor
> > Pretty simple, pretty clear.
> >
> > Now add a PWM solid state motor controller, with a LOT of freewheeling
> > diodes. This would be Zillas, and DCPs, and well yes Curtii, but with
> > less diodes.
> > Things get a bit harder to explain but it's this simple. You ask for
> > torque by standing on the throttle pot, this commands the controller to
> > increase the amps flowing in the motor, It lengthens the on part of the
> > PWM wave form, this lets more power flow from the batteries to the
> > motor. When the controller goes to the off part of the PWM wave the
> > current stops flowing from the batteries, and freewheels through the
> > controller's diodes. So you have short high current high voltage pulses
> > comming from the batteries, Once they are in the motor side of the
> > controller, the voltage spikes can't rise instantly becasue of the
> > inductance of the motor. So they raise the current but slowly raise the
> > voltage.
> > Or The big volts and low current get changed inside the controller to
> > Big amps and less voltage.
> > Why.... If you dumped the total battery voltage onto a stalled,or
> > stopped or heavily loaded motor, many thousands of amps would flow,
> > because the motor looks like a dead short at stalled speed. This is
> > contactor control, CHirp! ClanK! What broke? We want control. So most
> > of the time nothing near the total battery voltage is applied to the
> > motor, Even when you have many hundreds of amps flowing... the motor
> > voltage is always less than the battery voltage, so the motor current is
> > always higher that Batt current.
> > In testing, you get to see this...all the time, and with a dyno in my
> > shop, I got to play with it yesteday. I had 450 amps flowing in a
> > Advanced 8 incher, with only 43 motor volts across it, and about 2100
> > rpm. The most I saw in the battery loop was 180 amps and 88 volts. This
> > is a Batt:motor ratio of 2.5:1. If I load the motor down farther in RPM,
> > the ratio gets much higher. I saw 6:1 at one time. And lets also keep in
> > mind that amps is Torque. And by the way 450 amps is about 80 Ftlbs on
> > this motor. So all you Curtis
> > 400 amper folks out there, Foot to the floor is about 75 ftlbs of torque
> > on the motor shaft.
> > So a 400 amp controller, that makes or allows 400 amps to flow in both
> > the motor side and the battery side, is nice, but not really agressive
> > enough for a lot of us.
> > Then we had the 400 battery amp and 680 motor amp controllers, Much
> > better lauching, but kinda booring on the high side. A healthy 400 amp
> > Curtii would eventually outrun a 680 amp Auburn. Because the Auburn had
> > a 380 amp battery limit. At the high end... this counts, and the low end
> > the 680 motor current counts big time.
> > Then we had the Raptor 1200s. They would(and still do!) allow 1200 amps
> > from the battery, and there was no limit on motor peak amps, just 1082
> > amps of diodes, that could be pushed to 5 times that for short burst.
> > The gamble was that almost nobody would ever get out there for long.
> > Wrong! A badly arcing motor does that quite often.
> > Welded diodes told that story! These controllers still own most of the
> > less than 200 volt racing classes. Very powerfull, Rugged, but not
> > indestructable.
> > Now we have the Zillas. They regulate the motor current and the battery
> > current. They have a handle on all the issues. And you can program the
> > limits of both seprately. These are just now becoming available in
> > reasonable volume.
> >
> > Current limit on a AvDC 9??? there is none, just when it melts, arcs or
> > flys apart. Now what is prudent? This is a better question.
> > The motor does not come out of current limit, the controller does. And
> > Yes at 3500 rpm and 120 volts the 9incher won't draw much more than 400
> > amps So the controller See less than it's limits and goes wide open. Or
> > at this time the motor current and the battery current are the same.
> > Wide open at low voltage(For us racers!) In DCP controllers we turned on
> > a Yellow LED when this happened, so we would know that the controller
> > was "full on" at this time.
> >
> > DCP and Zillas would come out of current limit alot sooner. Since they
> > have a LOT higher limits.
> > Well I would say that the 9" inchers can take well over 1000 amps and
> > might have some pretty good hang time at 2000 amps, if properly timed
> > for both the amps and RPM that the amps will happen at. A 400 amp
> > controller... won't hurt a 9, A 1200 amper might cook it in about 5
> > minutes, if it can keep itself cool. At about 1500 amps you have
> > seconds of run time before a cool down rest is needed. At 2000 amps, We
> > don't really know yet, but not very long at all. Say 10 to 15 seconds.
> > Oh yea I think Advanced DC says the peak amps for a 9 incher is like 750
> > amps.
> > Yea Riiiiiiiight!
> >
> > --
> > Rich Rudman
> > Manzanita Micro
> > www.manzanitamicro.com
> > 1-360-297-7383,Cell 1-360-620-6266
> >
--
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
The problem with the world is stupidity. Not saying there should be a
capital punishment for stupidity, but why don't we just take the
safety labels off of everything and let the problem solve itself?
--- End Message ---
--- Begin Message ---
John Foster wrote:
What alternatives exist to E-Meters? I haven't heard of anything which
duplicates it (accurate Ah integration, programmable peukert etc). The
reason I don't have one is cost - with the pre-scaler it's well over
$300US.
The dual needle idea discussed a while back was really nifty, but harder
for the people who use my car to relate to.
Ideally I would like to have a display of estimated A-h remaining with a
nice big analog needle, like an automotive tach, not a digital display
nor a nearly invisible thin black needle.
Do any of the LED bar gauges work from a shunt, or are they all just
voltage based?
Thanks,
John Foster
John, please set your email client to output plain ASCII.
BRUSA BCM4xx Ah counter is an alternative which drives up to two analog
gauges to display Ah, volts or whatever (other than value on
its own display), so you get 3 parameters readout simultaneously.
Can be wired to the stock fuel gauge.
BRUSA counters do not have peukert correction stuff
and RS232 in them.
The "problem" is it is twice the cost of link 10 e-meter.
The price goes down as Euro/USD ratio improves, but don't
expect BCM to cost the same as an emeter.
Victor
--
Victor
'91 ACRX - something different
--- End Message ---
--- Begin Message ---
You can make a mechanical PWM type controller. Just a spinning drum and
some brushes. By adjusting the relative position of the brushes you can
from 0 to 100 percent duty cycles. To that you add synchronized mechanical
rectifier to take the place of the freewheel diodes.
Here is an example of a mechanical rectifier.
http://www.dself.dsl.pipex.com/MUSEUM/POWER/mechrect/mechrect.htm
Thanks,
Andre' B. Clear Lake Wis.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Peter VanDerWal
Sent: Monday, March 15, 2004 4:36 PM
To: EV
Subject: Re: motor current limit?
Now I'm confused.
What kind of controller doesn't use either contactors or electronics?
I suppose you could use a really big rheostat, but wouldn't that be
considered "electronics"?
--- End Message ---
--- Begin Message ---
Rich Rudman wrote:
Or those of us controller designers that would love to have a test mule.
I just had to use explorer... Yuk Gates stuff!!! to view the motor, and
it is a water cooled motor, and for $200 I would own one right now. $2K
not a chance, that nice buss motor that a scored.. is enough test mule
for me for now.
For 2K$ I would hand my cash to Victor... and have some support, and
design help.
I'm ready :-)
Seriously, 5133WS20 motor is one of the best ones for an EV.
This particular one, however, will be far more difficult
to adapt because of its shaft and front flange.
And, it is indeed overpriced for ebay tradition and for how it
is sold (as is, no suport, etc). It is not really overpriced
for what it is as a hardware goes (if claims that it is new
and not a production reject or something are true).
Looks like a gear box was removed. It would be valuable
if the seller will put it back so the user will have
normal output shaft.
I believe the source could be the same person from
hardware liquidators company in NY who called me
last year asking if I want a lot of 160 or so motors
for $500 each. I can be wrong, he didn't leave his name
back then.
--
Victor
'91 ACRX - something different
--- End Message ---
--- Begin Message ---
Here is a link to a thread on this subject from 1998.
http://solstice.crest.org/discussion/ev/199811/msg00817.html
Thanks,
Andre' B. Clear Lake Wis.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Andre Blanchard
Sent: Monday, March 15, 2004 5:05 PM
To: [EMAIL PROTECTED]
Subject: RE: motor current limit?
You can make a mechanical PWM type controller. Just a spinning drum and
some brushes. By adjusting the relative position of the brushes you can
from 0 to 100 percent duty cycles. To that you add synchronized mechanical
rectifier to take the place of the freewheel diodes.
Here is an example of a mechanical rectifier.
http://www.dself.dsl.pipex.com/MUSEUM/POWER/mechrect/mechrect.htm
Thanks,
Andre' B. Clear Lake Wis.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Peter VanDerWal
Sent: Monday, March 15, 2004 4:36 PM
To: EV
Subject: Re: motor current limit?
Now I'm confused.
What kind of controller doesn't use either contactors or electronics?
I suppose you could use a really big rheostat, but wouldn't that be
considered "electronics"?
--- End Message ---
--- Begin Message ---
How about a current shunt. Use the longest length of wire in the battery
circuit for the biggest signal and use a big filter.
Feed that signal into a voltage to frequency chip. Use the frequency output
to drive a stepper motor (with suitable power amp). Use the geared output
of the stepper motor to turn a screw, moving a pointer along a scale.
Just manually move the pointer to full when the battery is charged.
Or possibly you could use the voltage from the shunt to directly drive a
very low voltage motor driving the pointer. This would track current in and
out of the battery as the motor would change direction when the current
changed direction.
Thanks,
Andre' B. Clear Lake Wis.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Victor Tikhonov
Sent: Monday, March 15, 2004 4:45 PM
To: [EMAIL PROTECTED]
Subject: Re: E-meter alternatives
John Foster wrote:
What alternatives exist to E-Meters? I haven't heard of anything which
duplicates it (accurate Ah integration, programmable peukert etc). The
reason I don't have one is cost - with the pre-scaler it's well over
$300US.
The dual needle idea discussed a while back was really nifty, but harder
for the people who use my car to relate to.
Ideally I would like to have a display of estimated A-h remaining with a
nice big analog needle, like an automotive tach, not a digital display
nor a nearly invisible thin black needle.
Do any of the LED bar gauges work from a shunt, or are they all just
voltage based?
Thanks,
John Foster
John, please set your email client to output plain ASCII.
BRUSA BCM4xx Ah counter is an alternative which drives up to two analog
gauges to display Ah, volts or whatever (other than value on
its own display), so you get 3 parameters readout simultaneously.
Can be wired to the stock fuel gauge.
BRUSA counters do not have peukert correction stuff
and RS232 in them.
The "problem" is it is twice the cost of link 10 e-meter.
The price goes down as Euro/USD ratio improves, but don't
expect BCM to cost the same as an emeter.
Victor
--
Victor
'91 ACRX - something different
--- End Message ---
--- Begin Message ---
Jack Knopf wrote:
>
> Now that's some down to earth " Amps " talk. Now, "What If " someone had a
> 2000 amp, non-electronic, non-contactor controller. Out to the shop tonight!
Funny... What kind of controller???
--
Rich Rudman
Manzanita Micro
www.manzanitamicro.com
1-360-297-7383,Cell 1-360-620-6266
--- End Message ---
--- Begin Message ---
Chuck Hursch wrote:
I can't quite make the top of the
> hill, and have to downshift (losing a significant chunk of
> momentum) to 1st by the time I'm to 18mph or so.
yuKK!
You have a 500 amp 144 volt capable controller, or close to 100 Hp of
controller and a motor that can take it. Yet you run the machine at less
than 50 HP.
Man We need to build Evs that can do more than 18 MPH up a hill!! This
is a example of why I can't recomend a 96 volt system to anybody and
still look myself in the mirror!
The image of a Old slow in the way EV, when the cost of upping the
voltage only is minimal, Just doesn't do the EV image very good things!
Come on folks... we are trying to impress the Gas Guys, not get in thier
way!!
And take this from somebody who started out 10 years ago with 48 volts
and 2500 amps of floodeds. Been there done that, Goldie still has the
Scars.
--
Rich Rudman
Manzanita Micro
www.manzanitamicro.com
1-360-297-7383,Cell 1-360-620-6266
--- End Message ---
--- Begin Message ---
Sorry ,but mechanical rectifiers use contacts. Also the mechanical PWM
is just a rotating contactor.
Granted it's not the typical series parallel contactor controller, but
it's still a contactor controller.
On Mon, 2004-03-15 at 16:04, Andre Blanchard wrote:
> You can make a mechanical PWM type controller. Just a spinning drum and
> some brushes. By adjusting the relative position of the brushes you can
> from 0 to 100 percent duty cycles. To that you add synchronized mechanical
> rectifier to take the place of the freewheel diodes.
>
> Here is an example of a mechanical rectifier.
> http://www.dself.dsl.pipex.com/MUSEUM/POWER/mechrect/mechrect.htm
>
> Thanks,
> Andre' B. Clear Lake Wis.
>
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
> Behalf Of Peter VanDerWal
> Sent: Monday, March 15, 2004 4:36 PM
> To: EV
> Subject: Re: motor current limit?
>
> Now I'm confused.
>
> What kind of controller doesn't use either contactors or electronics?
>
> I suppose you could use a really big rheostat, but wouldn't that be
> considered "electronics"?
--
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
The problem with the world is stupidity. Not saying there should be a
capital punishment for stupidity, but why don't we just take the
safety labels off of everything and let the problem solve itself?
--- End Message ---
--- Begin Message ---
We have custody of an electric trike that was converted by Denet Lewis,
from Kona Waena High School that won their class in the Australian
race. This trike has a commercially built chassis. The drive system is
complete except for the motor, which is in pieces, and the batteries, which
are missing. It has a PMC 1204 controller. It was set up for 24V using
Hawker Genesis batteries, and claimed 20 mph and 20 miles range.
It is at our shop/home in Santa Cruz. Call or email if you are interested.
Mike Brown
Electro Automotive POB 1113 Felton CA 95018-1113 Telephone 831-429-1989
http://www.electroauto.com [EMAIL PROTECTED]
Electric Car Conversion Kits * Components * Books * Videos * Since 1979
--- End Message ---
--- Begin Message ---
This is an American Monarch OFFBOARD charger. It takes 220V input. It is
set up for 144V pack of Hawker Genesis. It will put out up to 31 amps
start and 9 amps finish. We used this for our race car. At the track on a
generator, it would charge twin parallel 144V strings of Hawkers from flat
to full in 4 hours. It's 15"w x 16" h x 12.5"L and weighs 120 lbs. Was
used very few times.
Cost new was $1200. Asking $600. Contact me off-list if you are interested.
Mike Brown
Electro Automotive POB 1113 Felton CA 95018-1113 Telephone 831-429-1989
http://www.electroauto.com [EMAIL PROTECTED]
Electric Car Conversion Kits * Components * Books * Videos * Since 1979
--- End Message ---
--- Begin Message ---
For your EV pleasure, and with some trepidation, I am announcing that I have once
again deluded myself into believing that I have the On-Road EV Inventory (Canada
and U.S. only) up to date once again. Currently at 1,775 entries (believed to be
in operation, with additional vehicles lost or no longer operational).
Much thanks to Mike Chancey for maintaining the EV Album, which I have linked to
wherever I could. (Mike, I hereby commit to getting at least one of my vehicles
into the Album in 2004.)
For those of you that would like to check it out, or review the entry (or entries)
pertaining to you, the entry point is at:
http://www.econogics.com/ev/evwhere.htm
Additions, updates or corrections should be e-mailed to me.
Darryl McMahon
--- End Message ---
