EV Digest 3912
Topics covered in this issue include:
1) Re: New power Wheels project help needed.
by [EMAIL PROTECTED]
2) RE: IEEE power & energy mag. Nov./Dec issue.
by "Shawn Waggoner" <[EMAIL PROTECTED]>
3) Re: Modular Chargers
by "Jay's peoplestar account" <[EMAIL PROTECTED]>
4) Re: variac turn-on? maybe ot
by "Rich Rudman" <[EMAIL PROTECTED]>
5) Re: Modular Chargers
by Lee Hart <[EMAIL PROTECTED]>
6) EaglePicher
by "Cliff Rassweiler" <[EMAIL PROTECTED]>
7) Re: variac turn-on? maybe ot
by Lee Hart <[EMAIL PROTECTED]>
8) Re: variac turn-on? maybe ot
by "Arthur Matteson" <[EMAIL PROTECTED]>
9) CSIRO SOLVE: Energy Storage - Why batteries may not live forever
by Brian Hay <[EMAIL PROTECTED]>
10) Re: Modular Chargers
by Ken Trough <[EMAIL PROTECTED]>
11) Help
by "Catherine C. Burgard" <[EMAIL PROTECTED]>
12) Deka Intimidator Sale
by "Raymond Knight" <[EMAIL PROTECTED]>
13) ADC 9.1" Motor Torque
by Nick Viera <[EMAIL PROTECTED]>
14) Re: ADC 9.1" Motor Torque
by David Dymaxion <[EMAIL PROTECTED]>
15) Re: ADC 9.1" Motor Torque
by "Tom Shay" <[EMAIL PROTECTED]>
16) Freewheeling a series motor
by Chris Zach <[EMAIL PROTECTED]>
17) Re: variac turn-on? maybe ot
by "Rich Rudman" <[EMAIL PROTECTED]>
18) Re: variac turn-on? maybe ot
by "Rich Rudman" <[EMAIL PROTECTED]>
19) Re: ADC 9.1" Motor Torque
by "Rich Rudman" <[EMAIL PROTECTED]>
20) Re: Help
by "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
21) Re: Help
by "Joe Smalley" <[EMAIL PROTECTED]>
--- Begin Message ---
Quoting Lee Hart <[EMAIL PROTECTED]>:
>
> Danger! The 12v charger in that UPS may not be isolated from the power
> line! If so, you could electrocute your child if he/she touches any of
> the wiring while that charger is connected!
>
Thanks, I'll check that, but the way I *INTEND* to do it is bury everything
under the seat where she can't get to it. The only thing coming out of the
truck will be the plug that goes into the wall.
> Wow... either you got a great deal on these, or are going to put $100
> worth of LEDs in your Powerwheels.
>
As I recall I paid about $20.00 at the swap meet for all of them. So I'll Likely
put 12 in each headlight and 3 in each tail light. Thats a total of 30 at a
rough cost of about $7.00 I can live with that.
James
--- End Message ---
--- Begin Message ---
Lawrence,
You have to have access to get to the article. Can you cut-n-paste here
for us? Thanks!
Shawn M. Waggoner
Florida EAA
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Lawrence Rhodes
Sent: Saturday, November 13, 2004 20:49
To: Electric Vehicle Discussion List
Subject: IEEE power & energy mag. Nov./Dec issue.
www.ieee.org/;power Electric Vehicles Charge Forward, Hybrids &
Hydrogen
article. IEEE sets the electrical standard for this country. Lawrence
Rhodes........
--- End Message ---
--- Begin Message ---
Another brainstorm about modular chargers: why not go whole hog and get
away completely from the troublesome concept of series connected cells?
Imagine attaching both a charger and "discharger" to each cell (large
lithium cells on the order of 500 to 1000 ah would work well for this
purpose). The discharger would boost the cell's 3 volts to high voltage
AC or DC current needed to power the car's motor. The combination
cell/discharger units would be ganged together to give the power and
range need by the car. One could visualize a car being powered by
perhaps 10 huge cells in this way. There would be no more problems with
reversed or imbalanced cells with the scheme. Fail-safe circuitry would
cut out the discharger if a cell or circuit failure occurred, but the
car would still be driveable using the power from the remaining cells,
with reduced range and performance.
Or perhaps the best approach would be to use one single gigantic (5000+
amp hour) cell to power the whole car; someone mentioned on this list
that a chinese-made electric scooter works this way.
--- End Message ---
--- Begin Message ---
----- Original Message -----
From: "Arthur Matteson" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Saturday, November 13, 2004 2:44 PM
Subject: Re: variac turn-on? maybe ot
> Thank you for replying Rich. This is very educational! and the best part
of
> the EV-List, IMHO.
>
> > And I am not sure who I am arguing with right now...
> > this thread is getting long.
>
>
> I think this is very important for us as engineers, just as it is
important
> for us as citizens to save energy. I still think this is very much
related
> to EVs and their usage as I hate to go off-topic.
>
>
> > Oh really??? fire up a transformer, and apply the hammer... YOU will get
a
> > LOT of stick, and so will everything in it's vicinity... The Efforts
used
> > to
> > quite down the 120 HZ humm from normal transformers is rather
> > comprehensive.
> > Yea most of the magnetic field is contained in the lams, but not all.
And
> > certialy not the fields that are generated outside of the lam stack, and
> > in
> > the feed lines and Secondard cables.
>
> You're right; I underestimated the leakage (I did say besides leakage
> though). Some is due to the wire, like you say, though. Toroids
typically
> exhibit less leakage, I believe, and I have mostly experimented with them
at
> 60Hz. I think toroids have higher inrush current as well.
>
I have a custom iso transformer that I had designed by Amveco, and they use
All Roids. They have ways of winding and adjusting the core mix to reduce
inrush. It was a point that I covered with the
Engineers. It's still pretty Thumpy, but no opened breakers.
Nobody...not even the Saftey Iso Nuts on this list....have Bellied up to
the Bar to buy one. OK. Got Iso, Don't Got customers....
Torroids were the only inductor shape that really ran right on our PFC fur
Ball design. That's why we will stay with them for greater than 60Hz work.
>
> > So permag effects are enginneered out of transformer Steel. Check the
> > hysterisis curves of Silicon Steel. It's a rather well documented
feature
> > of any magnetic material. I have Books full of this for Powdered iron
> > cores.
> > Want data???? Go look it up Micrometals.com.
>
> But it's exactly that - a hysteresis curve. Silicon steel is indeed one
of
> the best for remenance, but it isn't perfect. Just like 60Hz transformers
> overheat at 50Hz, because designers really want to minimize the already
> large number of turns, a small remenance can make a big difference.
Adding
> more turns to a transformer, I think, would help reduce this inrush
because
> saturation wouldn't be hit as easily.
Most folks don't design the cores to that close of tolerances. 50/60 is the
ball park, Unless you are being really cheap, or have a real tight market
specific use.
>
> I came across some great articles online:
>
> Here is a very detailed one:
> http://www.plitron.com/PDF/PETinrush.pdf
>
> http://sound.westhost.com/xfmr2.htm :
> --------------------------------------------------------------------
> *Silicon Steel (General Information) *
>
> Typically, soft (i.e. low remanence) magnetic steel will contain about 4%
to
> 4.5% silicon, which lowers the remanence of the steel and reduces
hysteresis
> losses. Normal mild steel, carbon steel or pure iron has quite a high
> remanence, and this is easily demonstrated by stroking a nail (or
> screwdriver) with a magnet. The nail will become magnetised, and will
> retain enough magnetism to enable it to pick up other nails. The addition
> of silicon reduces this effect, and it is very difficult to magnetise a
> transformer lamination strongly enough so it can pick things up.
>
> This is not to say that the remanence is zero - far from it. When a
> transformer is turned off, there will often be residual magnetism in the
> core, and when next powered on, it is common for the transformer to make
> noise - both toroids and E-I transformers can sometimes make a "boing"
noise
> when power is applied. That this phenomenon is intermittent is a
> combination of several factors ...
>
> o What was the polarity and magnitude of the mains at switch off
> o What is the polarity and magnitude of the mains at switch on
> o To what extent has the core de-magnetised itself between events
OK, the only thing we as designer can control is the turn off and the turn
on phase. Having a zero crossing switch that makes and break at the Null
point, first reduces the last shot, and reduces the next shot.
So... having zero crossing hardware is a real plus.
OK anybody got a Zero crossing relay that can take 208 200 amps??? and not
cost me $20 grand???
>
> The longer a transformer is left unpowered, the lower the remanent flux,
and
> the less likelihood there is of an excessively high inrush current. If
the
> mains is applied when at it's peak value, inrush current is at it's
lowest.
> Conversely, if the mains is applied at the zero crossing point, inrush
> current will be maximum - this is exactly the reverse of what you would
> logically expect. The inrush current lasts for several cycles, and is
made
> much worse with a rectifier and filter capacitor on the output. The
> capacitor is a short circuit when discharged, and large capacitors will
take
> longer to charge.
> --------------------------------------------------------------------
This hold true if you Buy the residual Mag as the primary effect on in rush
limits. I do not buy it. I buy the high line potentials at the peak of the
Sine wave as the primary effect in inrush surge.
So... for greatest effect only drop the line on the former of inductor at or
just before the zero crossing.
My guess is that the peak on effect is 4 powers of magnitude greater than
the last imprinted permag effrect. One is a 1 amp effect the other is a 1000
amp effect. It's clear what one I will pay attention too.
I will read all these posts, and I may change my attitude, But..... I doubt
it.
One way or the other, I will KNOW and have it in practice in short order.
Oh just for some data points.... a 75Kw transformer rated single
phase(or 2 legs) Starter contactor... is listed at $27,000 Bucks. This is a
dumb Slam bang starter. This single item is listed for more than the entire
projected cost of my Monster charger. Clearly the simple way is WAY too
expensive.
The design thread is total quite of the charger if not needing any power.
So... I want to power down the main transformer when not in actuall use.
That means I have to take control of bringing the Big boy on and off line,
While keeping the Brains and feature set active. So.... I get to start and
stop the transformer.... and pay for the gear to do so.
Right now I have a $200 two pole ac/DC rated breaker switch that lets me
light up the entire unit manually. This works... But on about %60 of the
makes, a couple of cycles dissapear off the North. Kitsap power grid.....
>
> A side note for those who are curious: The optional button on your
computer
> monitor called "Degauss" is meant to remove remenance. The only way it
can
> do this is to apply a damped sinusoid.
>
>
> > > This reduces clicking noises when the load is switched,
> > > and minimizes the influence of an inductive load, such as a
> > > lamp, heater...
> > Hold it Cowboy!!! .8 at steady state.
> > But...rethink what is happening... and when.
>
> Sorry, that was a terrible argument about the motor. I know *very* well
> that you are right about the inductance and power factor. But you agree
> that a heater and a lamp are mostly resistive, right?
>
> - Art
>
Yup for sure!!!
Umm Nichrome... has a really low Cold Resistance.... This lets some
pretty high surges happen until things warm up.
I am not sure why you put inductive loads and Tungsten lamps and heaters in
the same sentance.....
--- End Message ---
--- Begin Message ---
Jay's peoplestar account wrote:
> why not get away completely from the troublesome concept of series
> connected cells? Imagine attaching both a charger and "discharger"
> to each cell. The discharger would boost the cell's 3 volts to
> high voltage AC or DC current needed to power the car's motor.
> The combination cell/discharger units would be ganged together to
> give the power and range need by the car.
It's possible. But the devil is in the details. It would require lots of
high-current low-voltage wiring.
> One could visualize a car being powered by perhaps 10 huge cells
> in this way.
This has been done; many fork lifts are 36-72v (18-36 2v lead-acid
cells). These cells are of very large amphour capacity, like 500-2000ah.
But then, rather than a boost converter, they just design the motor and
controller to function directly with this low pack voltage. There are no
special problems making motors for any voltage. There are some practical
problems with electronic controllers for very large currents or voltages
(they get more expensive, and efficiency suffers a bit). But, a 36v
1400amp controller (50hp) controller is not out of reason.
> Or perhaps the best approach would be to use one single gigantic (5000+
> amp hour) cell to power the whole car; someone mentioned on this list
> that a chinese-made electric scooter works this way.
Yes; this has been done too, mainly with fairly low-power devices like
scooters. But for a car, the ultra high current would be a big design
challenge.
I think a more practical route to do this would be to build a contactor
controller, with (say) twelve 3.6v 500ah cells. The contactors can wire
them for 3.6v, 7.2v, 10.8v, 14.4v, 21.6v, or 43.2v. Use a 36v 1000a
forklift motor. Now you have a high-efficiency controller, and can wire
all the cells in parallel for automatic balancing.
--
"Never doubt that the work of a small group of thoughtful, committed
citizens can change the world. Indeed, it's the only thing that ever
has!" -- Margaret Mead
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Hi,
Anybody have any dealings with EaglePicher in regards to EV's?
Looking at the archives, I see they were involved with Horizon batteries
(formally Electrosource?) and sponsored a Tour de Sol competitor
http://www.mail-archive.com/[email protected]/msg04785.html.
Any opinions about their products?
Thanks
Cliff
www.ProEV.com
--- End Message ---
--- Begin Message ---
Rich Rudman wrote:
> I have a custom iso transformer that I had designed by Amveco,
> Toroids were the only inductor shape that really ran right on
> our PFC fur Ball design.
Why does your PFC care about the type of isolation transformer? Isn't it
drawing a sinusoidal input current? The transformer shouldn't matter.
> Nobody... not even the Saftey Iso Nuts on this list... have
> bellied up to the bar to buy one. OK. Got Iso, Don't Got customers.
I (for one) didn't know you had one. Maybe others are the same? Or, is
its price so high that they buy their own isolation transformer?
> Most folks don't design the cores to that close of tolerances.
> 50/60 is the ball park, Unless you are being really cheap, or
> have a real tight market specific use.
For little transformers, 50/60hz doesn't matter much. Plus, most are
built in the far east or somewhere where 50hz power is the norm anyway.
But the bigger the transformer, the more it costs you to include 50hz
operation. It adds 20% more iron, which means 15% more weight, and
larger size as well. Why pay for it if you don't need it?
> OK, the only thing we as designer can control is the turn off and
> the turn on phase. Having a zero crossing switch that makes and
> breaks at the Null point, first reduces the last shot, and reduces
> the next shot. So... having zero crossing hardware is a real plus.
>
> OK anybody got a Zero crossing relay that can take 208 200 amps?
At Honeywell, we had an "economizer" module. It powered the coil of the
contactor, and timed it so the contacts opened and closed at zero
crossings. It cost $20 or so, and was an option for their 30a, 40a, and
60a contactors.
Here's how it worked: You applied 24vac to the module, commanding it to
turn on. It waited for a zero crossing, then waited a fixed time, then
applied a regulated DC voltage to the coil. If you drive the coil with a
regulated voltage, then the pull-in and drop-out times are quite
consistent. For example, suppose this model contactor takes 10msec to
pull in. The module finds the zero crossing, waits 6.6msec, and powers
the coil. 10msec later, the contacts actually close. This is 16.6msec
after the zero crossing, or right at the next zero crossing at 60hz.
The same thing was done at turn-off. When the 24vac was removed, it held
the coil a fixed time and then let it drop out. The time was chose so it
turned off at then next zero crossing.
Limitations: It assumed you were switching a resistive load (heater or
light bulbs. It also assumed the load was powered from the same phase
that the coil power came from.
>> If the mains is applied when at its peak value, inrush current
>> is at its lowest. Conversely, if the mains is applied at the zero
>> crossing point, inrush current will be maximum - this is exactly
>> the reverse of what you would logically expect.
This agrees with what I found when designing microwave oven controls.
Turn on the transformer at the *peak* of the AC line voltage for minimum
inrush.
Rich, what may be confusing you is that if you power the transformer
with a solid-state relay, the voltage across the *relay* is
phase-shifted almost 90 deg. by the transformer's inductance. So, a
zero-crossing relay *will* turn on somewhere near the peak of the AC
line voltage.
>> The inrush current lasts for several cycles, and is made much
>> worse with a rectifier and filter capacitor on the output. The
>> capacitor is a short circuit when discharged, and large
>> capacitors will take longer to charge.
> This hold true if you buy the residual Mag as the primary effect
> on inrush limits. I do not buy it. I buy the high line potentials
> at the peak of the Sine wave as the primary effect in inrush surge.
> So... for greatest effect only drop the line on the transformer or
> inductor at or just before the zero crossing.
Rich, if you're looking for an analogy to explain transformer inrush
without residual magnetism, try this. An induction motor is a
transformer, right? It just has its secondary on a movable piece (the
rotor). Ok, lock the rotor and it's a transformer. What's the current
when you plug it in? HUGE! The secondary is shorted, so the primary
current is very large.
The current only drops as the rotor comes up to speed. In effect, the
mechanical load appears like resistance in its secondary. As secondary
current drops, primary current also drops.
A transformer with a bridge rectifier and capacitive load behaves the
same way. On turn-on, the secondary is shorted by the capacitor, so
inrush current is HUGE! But as the capacitor chargers, the secondary
current falls, so the primary current falls. Within a few cycles, the
secondary reaches its steady-state condition.
> Oh just for some data points.... a 75Kw transformer rated single
> phase(or 2 legs) Starter contactor... is listed at $27,000 Bucks.
> This is a dumb Slam bang starter. This single item is listed for
> more than the entire projected cost of my Monster charger.
> Clearly the simple way is WAY too expensive.
First, that's probably designed for a utility company, and built for a
40-year operating life.
Second, no utility company pays full list -- like buying tires, that's
just their opening bid.
> Umm Nichrome... has a really low Cold Resistance...
No, it's actually not too bad. We use nichrome specifically because its
resistance does not change too much between hot and cold.
Maybe you meant to say Tungsten has a really low cold resistance? This
is why a cold light bulb draws something like 10 times its normal
current.
> I am not sure why you put inductive loads and Tungsten lamps and
> heaters in the same sentance.
Because both draw high inrush currents.
--
"Never doubt that the work of a small group of thoughtful, committed
citizens can change the world. Indeed, it's the only thing that ever
has!" -- Margaret Mead
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Yup for sure!!!
Umm Nichrome... has a really low Cold Resistance.... This lets some
pretty high surges happen until things warm up.
I am not sure why you put inductive loads and Tungsten lamps and heaters
in
the same sentance.....
I didn't; that was an online quote. It quoted it to make us suspicious of
the source that said zero-cross switches were mainly for inductive loads.
Great detailed reply - I'll make sure to study it further. I believe I (and
probably others) am missing some of the background info. needed on your
designs, however. Not much either of us can do I suppose. I always read
your posts in their entirety.
Does Manzanita Micro do PSpice/Matlab/Simulink simulations of their
problems? The list, especially the younger of us on EVTech, would be very
interested in these. They go very far in proving one's point if implemented
correctly.
Arthur Matteson
- Custom Auto Electronics - Jackson, MI
- '80 Lectric Leopard, 'Little Homebrew AC'
http://mywebpages.comcast.net/awmatt
--- End Message ---
--- Begin Message ---
http://www.solve.csiro.au/1104/article5.htm
Regards,
Brian Hay.
--- End Message ---
--- Begin Message ---
I think a more practical route to do this would be to build a
contactor controller, with (say) twelve 3.6v 500ah cells. The
contactors can wire them for 3.6v, 7.2v, 10.8v, 14.4v, 21.6v, or 43.2v.
Use a 36v 1000a forklift motor. Now you have a high-efficiency
controller, and can wire all the cells in parallel for automatic
balancing.
This is the approach that is being taken by JPL and NASA. They call it a
"Switched Array Matrix" and they use it in conjunction with a matrix
controller, BMS and motor controller to be able to switch a pile of 30
batteries into different configuration strings for various voltages, or
switch to parallel to add capacity at a lower voltage instead or even
series/parallel strings to get the best of both worlds.
This system allows for great charging control as well as fault detection
and cell isolation in case of failure. VERY slick all in all. When I
complete my article on this, I'll post a link here.
-Ken Trough
Admin - V is for Voltage Megasite
http://visforvoltage.com
AIM - ktrough
FAX - 801-749-7807
message - 866-872-8901
--- End Message ---
--- Begin Message ---
Hi, we're new to the EV world and need some help.
I have a 1981 comutacar. We put in a 60 volt battery pack. We have a zivan K2
charger that plugs into a regular 110 outlet. It was adjusted by the
distributor for 60 volts. We also have a curtis controller 1205-201.
I took the madien voyage to the DMV and got there fine but it didn't have
enough power to get back so we towed it. We charged it up and it moves only at
a fraction of the speed at which it should.
Does anyone know how to check the charger to see if it is charging the
batteries correctly? My husband said the batteries should be bubbling when
fully charged and they are not, is that correct?
Does anyone know how to check the controller to see if it is working properly?
Any help would be appreciated.
Catherine
---------------------------------
Do you Yahoo!?
Check out the new Yahoo! Front Page. www.yahoo.com
--- End Message ---
--- Begin Message ---
Quick note: I am about to approach Deka, for whom I am a distributor, about
a large quantity of the new Intimidators. I belong to two racing forums and
one 4 x 4 forum. The thought being if a lot of people are interested, I
might be able to purchase them well below my normal cost. Then if I don't
mark them up, anyone interested could get a smoking deal. (EV listers will
get at cost, plus a $10.00/20.00 handling fee on the order, the other forums
will pay like cost plus $10 per battery. Paperwork takes time, and my book
keeper isn't free)
It would be helpful to me that if anyone might want to consider this, they
give a heads up. I am thinking something for the months of December and
January. I should be able to have them drop shipped to a dealer near you,
possible to your door even. Canadians and those from Ontario will have to
pay tax. Tax/duty free for everyone else. So this might be a cheap way to
replace a battery pack for some people. Let me know what you think, and I
will get some tentative pricing. (I am going for a promotional price, well,
well, below regular pricing).
--- End Message ---
--- Begin Message ---
Hi,
I keep getting asked questions like "So, how much torque can the
electric motor make?" when I talk to people about my Jeep Cherokee EV.
I've never been able to give a numerical answer as I don't know. I have
the Advanced DC 9.1" motor on a 160 volt system. I've got the KW and
Horsepower ratings at various voltages for it on the spec sheet which I
have, but can't seem to find torque ratings for it anywhere.
I guess I'd just like to know an approximate number for the max. torque
it can produce at the motor shaft so I can give others a more concrete
answer. I realize that the torque it actually produces in my application
will be dependent on the power system and drivetrain gearing.
Thanks
-Nick
1988 Jeep Cherokee 4x4 EV
http://Go.DriveEV.com/
--- End Message ---
--- Begin Message ---
P = T*w = T*2*pi*f (power = torque * 2 * pi * frequency)
T = P / (2 * pi * f)
T in Nm
P in kW
f in Hz
f = rpm / 60
So just plug it in, and convert Nm to ft*lb. You should then reduce
the number by maybe 20% to account for inefficiency losses.
--- Nick Viera <[EMAIL PROTECTED]> wrote:
> Hi,
>
> I keep getting asked questions like "So, how much torque can the
> electric motor make?" when I talk to people about my Jeep Cherokee
> EV.
>
> I've never been able to give a numerical answer as I don't know. I
> have
> the Advanced DC 9.1" motor on a 160 volt system. I've got the KW
> and
> Horsepower ratings at various voltages for it on the spec sheet
> which I
> have, but can't seem to find torque ratings for it anywhere.
>
> I guess I'd just like to know an approximate number for the max.
> torque
> it can produce at the motor shaft so I can give others a more
> concrete
> answer. I realize that the torque it actually produces in my
> application
> will be dependent on the power system and drivetrain gearing.
=====
__________________________________
Do you Yahoo!?
Check out the new Yahoo! Front Page.
www.yahoo.com
--- End Message ---
--- Begin Message ---
Torque depends on the current. Speed and voltage have practically
no effect on the torque. Performance curves for this motor which include
the torque vs. current curve are available at:
http://store.evparts.com/shopping/products/mt2119/mt2119torquecurvebyus.PDF
I'm not sure how accurate the torque vs. current curve is above about 600
amps. Ask Rod Wilde about the source and probable accuracy of the curve
beyond 600 amps.
----- Original Message -----
From: "Nick Viera" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Sunday, November 14, 2004 6:32 PM
Subject: ADC 9.1" Motor Torque
Hi,
I keep getting asked questions like "So, how much torque can the
electric motor make?" when I talk to people about my Jeep Cherokee EV.
I've never been able to give a numerical answer as I don't know. I have
the Advanced DC 9.1" motor on a 160 volt system. I've got the KW and
Horsepower ratings at various voltages for it on the spec sheet which I
have, but can't seem to find torque ratings for it anywhere.
I guess I'd just like to know an approximate number for the max. torque
it can produce at the motor shaft so I can give others a more concrete
answer. I realize that the torque it actually produces in my application
will be dependent on the power system and drivetrain gearing.
Thanks
-Nick
1988 Jeep Cherokee 4x4 EV
http://Go.DriveEV.com/
--- End Message ---
--- Begin Message ---
Question: I just picked up a "rusty" (actually it's not rusty and is in
great shape!) Elec-Trak tiller. I took the motor off for some review,
pulled the end cap, checked the bearings (great) and the brushes (great)
and put it all back together.
On a 12 volt battery the motor spins up to a certain speed and just
stays there. My question is this: It's a series wound motor, and I
thought that if you ran a series motor with no load it would self
destruct/overpseed. This one did not seem to do that, and my snowblower
motor doesn't seem to overspeed either. What are the conditions that can
cause overspeed on an unloaded series motor?
Chris
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--- Begin Message ---
----- Original Message -----
From: "Lee Hart" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Sunday, November 14, 2004 4:26 PM
Subject: Re: variac turn-on? maybe ot
> Rich Rudman wrote:
> > I have a custom iso transformer that I had designed by Amveco,
> > Toroids were the only inductor shape that really ran right on
> > our PFC fur Ball design.
>
> Why does your PFC care about the type of isolation transformer? Isn't it
> drawing a sinusoidal input current? The transformer shouldn't matter.
The inductor test was the main switcher inductor not a Iso
transfromer.
>
> > Nobody... not even the Saftey Iso Nuts on this list... have
> > bellied up to the bar to buy one. OK. Got Iso, Don't Got customers.
>
> I (for one) didn't know you had one. Maybe others are the same? Or, is
> its price so high that they buy their own isolation transformer?
>
My Cost is $275 in lots of 10. 2x that and shipping... and you have a list
price.
It cost $20 or so, and was an option for their 30a, 40a, and
> 60a contactors.
>
How about 200 amps on a 37.5 KVa Federal Pacific transfromer????
> Here's how it worked: You applied 24vac to the module, commanding it to
> turn on. It waited for a zero crossing, then waited a fixed time, then
> applied a regulated DC voltage to the coil. If you drive the coil with a
> regulated voltage, then the pull-in and drop-out times are quite
> consistent. For example, suppose this model contactor takes 10msec to
> pull in. The module finds the zero crossing, waits 6.6msec, and powers
> the coil. 10msec later, the contacts actually close. This is 16.6msec
> after the zero crossing, or right at the next zero crossing at 60hz.
This is very interesting....Cheap, easy to duplicate.
>
- this is exactly
> >> the reverse of what you would logically expect.
>
> This agrees with what I found when designing microwave oven controls.
> Turn on the transformer at the *peak* of the AC line voltage for minimum
> inrush.
>
> Rich, what may be confusing you is that if you power the transformer
> with a solid-state relay, the voltage across the *relay* is
> phase-shifted almost 90 deg. by the transformer's inductance. So, a
> zero-crossing relay *will* turn on somewhere near the peak of the AC
> line voltage.
>
> >> The inrush current lasts for several cycles, and is made much
> >> worse with a rectifier and filter capacitor on the output. The
> >> capacitor is a short circuit when discharged, and large
> >> capacitors will take longer to charge.
A couple of points. First I don't intend to have the chargers on when I
power up the transformer. The current schematic has the chargers come on
after the transformer has settled down.
So... No caps No rectifier in line on the inrush. I also intend to sequence
on the chargers with Triacs.... if the client goes for "Full control".
You can get 50 and 75 amps 208 to 240 V SSRs... YOU can't GET 200 amp 208VAC
modules. You have to go discrete at that level.
>
> > This hold true if you buy the residual Mag as the primary effect
> > on inrush limits. I do not buy it. I buy the high line potentials
> > at the peak of the Sine wave as the primary effect in inrush surge.
> > So... for greatest effect only drop the line on the transformer or
> > inductor at or just before the zero crossing.
>
> Rich, if you're looking for an analogy to explain transformer inrush
> without residual magnetism, try this. An induction motor is a
> transformer, right? It just has its secondary on a movable piece (the
> rotor). Ok, lock the rotor and it's a transformer. What's the current
> when you plug it in? HUGE! The secondary is shorted, so the primary
> current is very large.
>
> The current only drops as the rotor comes up to speed. In effect, the
> mechanical load appears like resistance in its secondary. As secondary
> current drops, primary current also drops.
OK this makes a lot of sense. BUT... I will have no secondary current...
Inrush and power on is the only load the primary will have.
The secondary will be OPEN on start up of the primary.
>
> A transformer with a bridge rectifier and capacitive load behaves the
> same way. On turn-on, the secondary is shorted by the capacitor, so
> inrush current is HUGE! But as the capacitor chargers, the secondary
> current falls, so the primary current falls. Within a few cycles, the
> secondary reaches its steady-state condition.
>
> > Oh just for some data points.... a 75Kw transformer rated single
> > phase(or 2 legs) Starter contactor... is listed at $27,000 Bucks.
> > This is a dumb Slam bang starter. This single item is listed for
> > more than the entire projected cost of my Monster charger.
> > Clearly the simple way is WAY too expensive.
>
> First, that's probably designed for a utility company, and built for a
> 40-year operating life.
>
> Second, no utility company pays full list -- like buying tires, that's
> just their opening bid.
>
> > Umm Nichrome... has a really low Cold Resistance...
>
> Maybe you meant to say Tungsten has a really low cold resistance? This
> is why a cold light bulb draws something like 10 times its normal
> current.
You are correct on that point. Normal steel shows that problem also.
I did a load bank with Signode strapping steel once, it varried by about
5x hot to cold.
High power resistors are very tame, and I use them for chicken resistors
on controller because they are tame.
>
> > I am not sure why you put inductive loads and Tungsten lamps and
> > heaters in the same sentance.
>
> Because both draw high inrush currents.
> Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
>
OK Lee I learned some things here.
I still don't buy the switch at Peak instead of zero cross. That will have
to be taught to me by some data collecting.
Shorted response to save band width.
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--- Begin Message ---
Joe does the Matlab, PSpice work.
I get to build it and blow it up and hand the pieces back to Joe with some
crass comments about simulate this!! And there might be a few errors, While
I still am smoking.....
No Joe's sim runs are usuaually very tight, and on the money. We will be
doing some of the Iso Buck stage design on a simulator. The last run showed
why the big boys don't do it single stage.
A lot of us power supply mongers dream of doing PFC Iso in a single stage.
The show stopper is a 1200 IGBT that dumps 2x the losses that the entire
Boost stage does. Hence no savings... watts or cost.
Lee has been educating me today... but I just don't buy the power up at
peak not trough.
I suppose that thinking that the transformer takes a few dozzen cycles to
wind up, just like a induction motor spinning up to Sync speed really makes
things clear. But I have had many cycles firing up the monster charger,
sometimes it's pretty intimidating other times it's tame... there is a right
time and wrong time. My finger can't do the 16.67 Msec delay....yet....
As I recall I am on EV tech also....
Arthur What happened to that Classs D Subwoofer Audio amp????
GOT code, and a schematic????
I need some Siesmo Acustics..... Got, many 1/2 bridge modules to play
with.....
----- Original Message -----
From: "Arthur Matteson" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Sunday, November 14, 2004 3:53 PM
Subject: Re: variac turn-on? maybe ot
> > Yup for sure!!!
> > Umm Nichrome... has a really low Cold Resistance.... This lets some
> > pretty high surges happen until things warm up.
> > I am not sure why you put inductive loads and Tungsten lamps and heaters
> > in
> > the same sentance.....
>
> I didn't; that was an online quote. It quoted it to make us suspicious of
> the source that said zero-cross switches were mainly for inductive loads.
>
> Great detailed reply - I'll make sure to study it further. I believe I
(and
> probably others) am missing some of the background info. needed on your
> designs, however. Not much either of us can do I suppose. I always read
> your posts in their entirety.
>
> Does Manzanita Micro do PSpice/Matlab/Simulink simulations of their
> problems? The list, especially the younger of us on EVTech, would be very
> interested in these. They go very far in proving one's point if
implemented
> correctly.
>
> Arthur Matteson
> - Custom Auto Electronics - Jackson, MI
> - '80 Lectric Leopard, 'Little Homebrew AC'
> http://mywebpages.comcast.net/awmatt
>
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--- Begin Message ---
About 500 lbs of torque with 2000 amps
about 200 with 1000 amps
EVparts has amps/torque, and volts and RPM curves.
I have copies somewheres.
Note... you get these torque numbers only if you are moving the amps and are
NOT making fireballs at the same time. Having the comm dissapear into a
plasma ball, and you get a LOT less torque for the same amps...You get more
light, and lots of copper snot!!
----- Original Message -----
From: "Nick Viera" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Sunday, November 14, 2004 6:32 PM
Subject: ADC 9.1" Motor Torque
> Hi,
>
> I keep getting asked questions like "So, how much torque can the
> electric motor make?" when I talk to people about my Jeep Cherokee EV.
>
> I've never been able to give a numerical answer as I don't know. I have
> the Advanced DC 9.1" motor on a 160 volt system. I've got the KW and
> Horsepower ratings at various voltages for it on the spec sheet which I
> have, but can't seem to find torque ratings for it anywhere.
>
> I guess I'd just like to know an approximate number for the max. torque
> it can produce at the motor shaft so I can give others a more concrete
> answer. I realize that the torque it actually produces in my application
> will be dependent on the power system and drivetrain gearing.
>
> Thanks
>
> -Nick
> 1988 Jeep Cherokee 4x4 EV
> http://Go.DriveEV.com/
>
--- End Message ---
--- Begin Message ---
At 06:27 PM 11/14/2004, you wrote:
Hi, we're new to the EV world and need some help.
I have a 1981 comutacar. We put in a 60 volt battery pack. We have a
zivan K2 charger that plugs into a regular 110 outlet. It was adjusted by
the distributor for 60 volts. We also have a curtis controller 1205-201.
I took the madien voyage to the DMV and got there fine but it didn't have
enough power to get back so we towed it. We charged it up and it moves
only at a fraction of the speed at which it should.
Does anyone know how to check the charger to see if it is charging the
batteries correctly? My husband said the batteries should be bubbling
when fully charged and they are not, is that correct?
Do you have an "Emeter" or a "Link 10" in your car? If not, you
should think about installing one, or something like it. It tells you how
the batteries are doing.
Regardless, there must be a voltmeter in the car, or at least you
need to get a hand held voltmeter to check the state of the batteries and
the function of the charger. An ammeter would also be a big help.
Near the end of the charge, the pack voltage should be over 72
volts. A short while after the charger goes off, the pack voltage should be
something close to 65 volts, give or take a couple of volts. Check the
voltage on each battery. They all should be within a couple of tenths of a
volt of each other if they are all healthy.
You will need a hydrometer. (I assume you have flooded batteries.)
Check the specific gravity of the electrolyte with the hydrometer to
determine the exact state of charge. A little cheapie one (with the plastic
balls) from the auto parts store will do, but you will eventually want to
get a "real" hydrometer with a float with numbers, so you might as well
spend the few extra bucks right away.
Leaving lead-acid batteries discharged is very bad for them. If
the charger is not working correctly, put a charge on them however you can.
Charge them all individually with a 12 volt car charger if nothing else is
available. If you leave them dead for more than a day or two, they will be
damaged.
Does anyone know how to check the controller to see if it is working properly?
It is unlikely that the controller is the problem. It sounds like
the batteries are not charged.
The simple test is to observe the pack voltage when you attempt to
move the car. If the pack voltage (at the controller input lugs) is holding
55 volts or so, and the car is not moving properly, the controller has a
problem. If the pack voltage dips badly, there is a problem with the
battery pack or the pack connections.
Here are the things you need to do first:
1) Measure the pack voltage.
2) Turn on the charger and measure the pack voltage.
3) Measure and record the individual battery voltages.
4) Take a few hydrometer readings and record them.
5) Drop a note to this list with your readings.
We'll tell you what to do based on what the readings are.
There are experienced EVers all over the world. It is likely that
one of the 800 folks on this discussion list live near by and can help with
the diagnosis. What part of the world do you live in?
_ /| Bill "Wisenheimer" Dube'
\'o.O' <[EMAIL PROTECTED]>
=(___)=
U
Check out the bike -> http://www.KillaCycle.com
--- End Message ---
--- Begin Message ---
A 48 volt car will charge up to 60 volts at the end of charge. If you put 5
each 12 volt batteries or 10 each 6 volts batteries in the car, the charger
will need to go to 72 volts. Make sure the charger goes up to 72 volts. If
it only goes up to 60 volts, then it is a 48 volt charger and is the wrong
charger for your application.
If you do have a 48 volt charger, take out 12 volts of battery to reduce the
nominal pack voltage to 48 volts and then charge the pack. If is charges
correctly, then you need to either 1) get another charger to match the
battery pack or 2) reduce the number of batteries to match the charger.
Joe Smalley
Rural Kitsap County WA
Fiesta 48 volts
NEDRA 48 volt street conversion record holder
[EMAIL PROTECTED]
----- Original Message -----
From: "Catherine C. Burgard" <[EMAIL PROTECTED]>
To: "EV List" <[EMAIL PROTECTED]>
Sent: Sunday, November 14, 2004 5:27 PM
Subject: Help
> Hi, we're new to the EV world and need some help.
>
> I have a 1981 comutacar. We put in a 60 volt battery pack. We have a
zivan K2 charger that plugs into a regular 110 outlet. It was adjusted by
the distributor for 60 volts. We also have a curtis controller 1205-201.
> I took the madien voyage to the DMV and got there fine but it didn't have
enough power to get back so we towed it. We charged it up and it moves only
at a fraction of the speed at which it should.
> Does anyone know how to check the charger to see if it is charging the
batteries correctly? My husband said the batteries should be bubbling when
fully charged and they are not, is that correct?
> Does anyone know how to check the controller to see if it is working
properly?
> Any help would be appreciated.
> Catherine
>
>
>
> ---------------------------------
> Do you Yahoo!?
> Check out the new Yahoo! Front Page. www.yahoo.com
--- End Message ---
