EV Digest 6172
Topics covered in this issue include:
1) Austin EV website query - seeking Citroen "Chuck"
by James Neale <[EMAIL PROTECTED]>
2) CVT for solar EV, RE: Motor selection for 2KW PV solar only drag race =
LONG
by "jerryd" <[EMAIL PROTECTED]>
3) Re: Need isolation transformer
by "Phil Marino" <[EMAIL PROTECTED]>
4) Re:Current Eliminator dragster news
by "Mike Phillips" <[EMAIL PROTECTED]>
5) Re: Austin EV website query - seeking Citroen "Chuck"
by Mike Chancey <[EMAIL PROTECTED]>
6) Re: Duralast batteries?
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
7) Re: Duralast batteries?
by "Paul G." <[EMAIL PROTECTED]>
8) make your own batteries
by Jeremy Rutman <[EMAIL PROTECTED]>
9) Re: Duralast batteries?
by "Roland Wiench" <[EMAIL PROTECTED]>
10) Re: Need isolation transformer
by Chris Zach <[EMAIL PROTECTED]>
11) Re: Who killed the Electric Car in Ohio
by murdoch <[EMAIL PROTECTED]>
12) Leaking motor
by Storm Connors <[EMAIL PROTECTED]>
13) Re: Leaking motor
by "Roland Wiench" <[EMAIL PROTECTED]>
14) Battery Heater Pads and Kodiak C-600 FS
by "Rush" <[EMAIL PROTECTED]>
15) "Files" section on Yahoo Groups?
by Craig Burton <[EMAIL PROTECTED]>
16) Re: NiMH Battery Pack Poll
by Mike Sandman <[EMAIL PROTECTED]>
17) Re: hello
by Mike Sandman <[EMAIL PROTECTED]>
18) Re: Need isolation transformer
by Chris Zach <[EMAIL PROTECTED]>
19) Re: Need isolation transformer
by "Arthur W. Matteson" <[EMAIL PROTECTED]>
20) Re: Need isolation transformer
by "Roland Wiench" <[EMAIL PROTECTED]>
21) Re: Need isolation transformer
by Steve Condie <[EMAIL PROTECTED]>
22) Ev controllers - 4th option.
by "Danno none" <[EMAIL PROTECTED]>
23) 2 Segways spotted
by Rod Hower <[EMAIL PROTECTED]>
24) Re: Need isolation transformer
by James Massey <[EMAIL PROTECTED]>
25) Re: Ev controllers - 4th option.
by Rod Hower <[EMAIL PROTECTED]>
--- Begin Message ---
Hi all
First post on list but been a reader for a while. Am considering doing a
compact MPV conversion once I get some finances into the clear.
My q : Does anyone know of (or is) the "Chuck" that did this
conversion.... http://www.austinev.org/evalbum/868
No contact details are on his/her page and I'm keen to ask some q's.
cheers
------------------------------------------------------------------------
James Neale
<http://www.promotionstudios.com>ProMotion Studios
GPO Box 7027
Sydney NSW
2001 Australia
studio: 61-2-9247-2788
mobile: 61-(0)402-39-2233
e: [EMAIL PROTECTED]
w: www.promotionstudios.com
--- End Message ---
--- Begin Message ---
Hi Tim and All,
The first car to cross the US, The Wilson, had a
CVT made by using a friction wheel against a drive disc,
moving the driven wheel closer and farther from the
centerline to change gears. And it was one of the few things
not to break!!! Using a rollerblade wheel as the drive wheel
and an alum disc, like used for table disc sanders or made
from scratch with a pully and an Alum plate, ect should work
well for your short term needs.
Hope This helps
Jerry Dycus
----- Original Message Follows -----
From: "Offgrid Engineering" <[EMAIL PROTECTED]>
To: "'Lee Hart'" <[EMAIL PROTECTED]>,
<[email protected]>
Subject: RE: Motor selection for 2KW PV solar only drag race
= LONG
Date: Sat, 25 Nov 2006 18:02:49 -0800
>Hi Lee:
>Sorry I did not give a very complete reply earlier. I'll
>try to be more thorough now that I have time. I'll use your
>numbers:
>
>1. I totally agree array direct as soon and as long as
>possible will be the best course. The car must peak power
>trace the array, and "peak efficiency track" the motor to
>have max acceleration. And yes it is well understood the
>panels peak power and continuous power, unlike batteries,
>is the same thing.
>2. Yep Vmp = 56V and 35.7 amps
>3,4. The CVT is a solution that can keep the motor at the
>same RPM, and it is a possible solution here. We have
>modeled the CVT using a number of different pulley sizes
>and shapes. While we will continue to work on this, we are
>a bit dubious that it will be reliable, efficient, give
>high repeatability, have an operation curve close to what
>we need, be able to be built by high school students. WE
>are interested if anyone has built a simple efficient CVT,
>and we won't give up developing ours, thanks for the ideas!
>
>I was assuming a buck pwm would be the better choice, and
>my calculations given earlier assume that to be the case,
>but this may turn out not to be true. The motor needs to
>accerate to full rpm in the very beginning, and would you
>like to use max array current of about 36 amps or maybe 150
>amps, given the same drive ratio? Now one could use a
>combination of say DC-DC converter making 12V at 150 amps
>to get RPMS up and then switch to a CVT, and we are looking
>at that too. But I do believe in KISS.
>
>If a CVT were, used, I agree that the pmdc motor would be
>the better choice, for the high efficiency, but if a pwm
>controller is used, using the controller as the
>transmission, maybe the series motor is not such a bad
>choice. Once I get the curves (have an email to ADC) I can
>put them in the model to compare to AGNI.
>
>Thanks again...
>
>Tim
>
>
>-----Original Message-----
>From: Lee Hart [mailto:[EMAIL PROTECTED]
>Sent: Saturday, November 25, 2006 1:29 AM
>To: [email protected]
>Subject: Re: Motor selection for 2KW PV solar only drag
>race = LONG
>
>Offgrid Engineering wrote:
>> I think PMDC is a good choice, but a series motor might
>be good too
>
>Your solar dragster is a special-case problem, because your
>PV panels are the only source of power, and they are a
>constant power device. Loading them heavier or lighter than
>optimum produces less power, which means you accellerate
>slower (and lose the race).
>
>So, you want your motor/controller/transmission to load the
>panels at (about) their peak power point throughout the
>race, as the car accellerates from 0 to maximum speed.
>
>Here's how I was approaching the problem:
>
>1. The most efficient controller is NONE. A DC motor,
>connected
> directly to the PV panels. The throttle is just an
>"on/off" switch.
>
>2. The peak power point occurs at a particular voltage and
>curent.
>
>3. So, the motor will run at a constant voltage and
>current. That
> implies constant rpm and torque, regardless of vehicle
>speed.
>
>4. And that implies a CVT (continuously variable
>transmission).
>
>5. Do some calculations using your PV panel's peak power
>(2kw?),
> motor efficiency at that power (90%?), and the weight of
>the
> car+driver. Find the resultant wheel rpm vs. time with
>this
> constant horsepower.
>
>6. Now, using the motor's constant rpm at this power, you
>can compute
> the CVT ratio as a function of time, to keep the motor
>loaded to
> its correct speed and torque.
>
>7. Design the pulleys of your CVT to achieve this change in
>ratios.
> You can have the ratio change linearly by using a flat
>band, or
> have it change exponentially with a wire that winds up
>zig-zag
> fashion between two unequal-width spools.
>
>> In Excel we modeled the "simple CVT" you suggest and it
>> is a fairly linear proportion curve. When you overlay
>> this curve over the exponential torque curve from a
>> motor, the two do not line up very well.
>
>You're missing that you have a fixed power from the PV
>panel. Therefore, the motor has only one operating point.
>There is no torque-speed curve; just one operating point
>for maximum accelleration.
>
>Now, you could use a PWM controller to vary motor voltage
>while maintaining peak power loading of the PV panels. But
>I think you will find that this automatically means running
>the motor at points away from its peak efficiency.
>
>But, it still might "win" if the extra losses in the
>controller and motor were less than losses saved by
>replacing the CVT with a fixed or X-speed transmission.
>--
>"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 ---
From: "Roland Wiench" <[EMAIL PROTECTED]>
Reply-To: [email protected]
To: <[email protected]>
Subject: Re: Need isolation transformer
Date: Sun, 26 Nov 2006 00:32:00 -0700
Hello Chris,
We normally purchase transformers from a wholesale electrical supply house.
They will be either a Square D, General Electric, Westinghouse. You may
have
to go to a electrical shop to get a purchase order to buy from a wholesale
electrical supply company.
If you are isolation for power only, then use a Single Phase - General
Purpose Transformer 3kva 60 Hz Dry Type Metal Clad type rated at 600 volts
and below standard stock transformer with 240/480 primary that have four
taps and a secondary that has 120/240 with four taps.
These are the cheapest type of transformer which will cost about $500.00
You parallel the primary for 240 volts input and series the secondary leads
for a three lead output of 120/240 volts.
I bought a transformer with the exact same specs as you describe, Roland,
on Ebay for $90 including shipping ( about 2 years ago) . It was brand new
in the box, and GE brand. I seem to remember it weighed about 75 pounds.
It's a relatively cheap, easy way to have an isolated charger. It's mounted
to my garage wall, so the weight is not a problem.
So, If you're patient, you may find one on Ebay with a similar price.
Phil
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--- End Message ---
--- Begin Message ---
If you are breaking out then you are sandbagging too much ;)
I hope you nail it on the 16th.
Mike
--- In [EMAIL PROTECTED], [EMAIL PROTECTED] wrote:
>
> The Thanksgiving Shootout.I drove the CE 6 rounds today to a
qt.final round
> and broke out of my dial by .003.The finish paid my entry and added
a 150.to
> the war chest.Next and last big race of the year dec.16.Its the King
of the
> track inventional.You had to win at least 1 nhra summit race during
the year to
> qualify to race.Winning will pay all entrys to race next year.
Dennis Berube
>
--- End Message ---
--- Begin Message ---
James Neale wrote:
Hi all
First post on list but been a reader for a while. Am considering
doing a compact MPV conversion once I get some finances into the clear.
My q : Does anyone know of (or is) the "Chuck" that did this
conversion.... http://www.austinev.org/evalbum/868
No contact details are on his/her page and I'm keen to ask some q's.
cheers
I forwarded your email on to Chuck, hopefully he will
respond. Virtually all entries in the EV Album have email addresses,
some folks just don't want theirs displayed, but I do still have
access to them. Out of respect for their privacy I do not give them
out, but I can forward messages to them.
Thanks,
Mike Chancey
Webmaster
EV Photo Album
http://evalbum.com
--- End Message ---
--- Begin Message ---
Batteries for EV's are special. Typical automotive batteries will not do.
Lawrence Rhodes.......
----- Original Message -----
From: "Brandon Kruger" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Saturday, November 25, 2006 6:22 PM
Subject: Re: Duralast batteries?
> It said "Reserve Capacity" and I took that for Ah. I could be
> mistaken. I am kind of new to this.
>
> Brandon Kruger
>
> On 11/25/06, Danny Miller <[EMAIL PROTECTED]> wrote:
> > Are you sure that was Ah and not "reserve minutes"?
> > It is unusual to find rating in Ah on these batteries.
> >
> > Danny
> >
> > Brandon Kruger wrote:
> >
> > > I checked out my local Autozone today to check out their battery
> > > selection and found only the Duralast batteries. I looked at
> > > capacities and prices. I found the 65DLG. The specs seem to be 12V
> > > 165Ah $79.99 and didnt feel heavier than 40lbs. This seems too good
> > > to be true. Can someone find out more about these batteries?
> > >
> > >
> > > Brandon Kruger
> > >
> >
> >
>
--- End Message ---
--- Begin Message ---
On Nov 24, 2006, at 8:27 PM, Brandon Kruger wrote:
I checked out my local Autozone today to check out their battery
selection and found only the Duralast batteries. I looked at
capacities and prices. I found the 65DLG. The specs seem to be 12V
165Ah $79.99 and didnt feel heavier than 40lbs. This seems too good
to be true. Can someone find out more about these batteries?
As near as I can tell Marine deep cycle and SLI Duralast batteries are
available. I think the 65-DLG is an SLI battery (I can only find a
little info online.)
SLI (Starting, Lighting, Ignition - car starting batteries) are not
acceptable for deep cycle duty. They will last less than 50 cycles in
deep cycle duty.
Marine batteries are something between a true deep cycle battery and an
SLI battery. They can be used in EVs but their life span is perhaps 1/2
of a traction battery. Group 27 or Group 31 size Marine batteries have
been pressed into EV service when a lighter pack (compared to using 6
or 8 volt golf cart batteries) is needed.
Duralast batteries are made by Johnson Controls. They generally have a
good reputation.
Paul "neon" G.
--- End Message ---
--- Begin Message ---
What I see a lot in research is that 95% of the work done involves
copying stuff
somebody else did. I was suggesting - if you're gonna be fooling around
with your own energy storage, at least try something
new e.g. high voltage caps with your own electrolyte on the off-chance
of hitting something interesting ,instead of replicating 100 year old
stuff thats known.
Even if they were FREE, the weight and volume prevent the current
capacitor technology from being used for anything but a single
acceleration. As a matter of fact they're also quite expensive.
Jeremy Rutman
Technion Physics Dep't
Haifa 32000
Israel
972 4 8293669
--- End Message ---
--- Begin Message ---
To see how much usable AH there is in this Duralast battery with a Reserved
Capacity of 165 minutes at 25 amps:
165 RC / 60 minutes = 2.75 hours
2.75 hrs x 25 amps = 68.75 AH at 25 amps
Deep cycle batteries are normally rated at a Reserved Capacity of 75 amps,
so a 165 reserved capacity battery rated for 25 amps would be about 1/4 the
rating at 75 amps:
165 RC / 4 = about 41 minutes or .68 hours
.68 hrs x 75 amps = 51 AH
Usable AH of deep cycle lead-acid battery is about 50%.
Usable AH of a starting, ignition battery is about 20% so:
.20 x 51 AH = about 10 AH at 75 amps for 8 minutes
Now if you was to crank over a motor at 300 amps, this would reduce this
about another 4 times or to 2 minutes of cranking times.
This is about the maximum amount of time you can crank over a motor or
starter motor at that ampere which the battery may go below 80% or more SOC
(State of Charge).
Roland
If you are cranking over a motor at 300 amps
--- End Message ---
--- Begin Message ---
I would somewhat prefer an isolation transformer, however a buck type
would work as well for now. Does anyone know where a 240/208 buck could
be found?
Chris
Steven Ciciora wrote:
Does it have to be an isolation transformer? A
non-isolated bucking transformer would be much smaller
(read: cheaper).
- Steven Ciciora
--- Chris Zach <[EMAIL PROTECTED]> wrote:
A question: I need an isolation transformer. 3kw
capacity, 240 volts to
208 volts. This is for safety and to step down 240
volts a bit for
faster charging.
Anyone know where might I find one of these? Are
they items that can be
found in a local electrician's shop?
Thanks
Chris
____________________________________________________________________________________
Do you Yahoo!?
Everyone is raving about the all-new Yahoo! Mail beta.
http://new.mail.yahoo.com
--- End Message ---
--- Begin Message ---
The Cobasys manufacturing plant is in Ohio, and an interview with the
Ovshinskys (before Mrs. Ovshinsky died) is prominently featured in the
film. So, in addition to the Myers motors issue, there is an
correlation to how the events and opinions relayed in the documentary
might bear on employment and manufacturing in Ohio, not to mention on
transportation.
When Sony Pictures Classics first released the list of planned
theaters, there was a very distinct lack of Ohio theaters in the list
(maybe one or two) compared to Ohio's status as a populous state with
strong auto-industry ties (I think). Some of us brought this to the
attention of SPC, and the result seemed to be the scheduling of some
additional theaters.
Still, your post may reveal some pent-up demand. 26 ahead of you?
Certainly interesting. How often do you see that?
On Sat, 25 Nov 2006 13:42:25 -0800 (PST), you wrote:
>I just asked the lady at the front desk of our local
>library if they had "Who killed the Electric Car".
>They said the DVD is on order and there are 26 holds
>in front of my request! I had no idea there would be
>this kind of demand for that movie in Northeast Ohio.
>Maybe Myers Motors inspired some interest! They are
>located about 10 miles from this library and the local
>newspaper, "The Akron Beacon Journal" has had a couple
>of articles about Myers Motors recently.
>Maybe David Roden is on that waiting list?
>Anyhow, just kind of surprised at the long waiting
>list.
>Rod, visiting the local library with the kids and
>driving the wifes SUV :-(
>
--- End Message ---
--- Begin Message ---
I am reading 70V between the positive side of my pack and the chassis ground.
If I remove the negative lead to the motor, there is no voltage between the
pack and ground. If I close the contactor which is at the positive end of the
pack, I read 25v from the negative end of the pack to the chassis and 50v from
the positive end of the pack to chassis.
I assume this is a problem. Am I going to have to go inside the motor to find
out what is leaking? FWIW, it seems to be running fine. As a Jeep owner, I know
that is the sure sign of a major problem. Any time it is running fine, look out.
Thanks,
storm
--- End Message ---
--- Begin Message ---
Hello Storm,
This may be normal as time goes on. There is brush dust build up in side
the motor, which provides a conductive path down the face of the commentator
to the motor shaft.
When my motor was new, it read over 20 megohms to ground from the armature
leads to the case of the motor. When it gets down below 30k ohms it is time
to clean the motor.
Another test I did before I did this, was turn on the charger and turn off
all the lights. I seen slight arcing between some batteries and the metal
frame that was holding the batteries at one time. Also there was some arc
over from the commentator to the motor shaft.
I remove the motor, dissemble it, clean it with a motor cleaning solution
that I got from a motor shop. Also pick up some spray type of motor enamel
from them.
After I clean the motor, I spray the entire inside of the motor case and
field windings until they were glass smooth. Also apply several coats of
motor enamel on the face of the commentator down to the shaft and up to the
bearing surfaces. Assembly the motor and install a large Dayton Blower at
150 CFM on the brush cover which blows out the brush dust out the rear
bottom of the motor which has a screen grill.
This motor then ran 20 years before I remove it again to do the same
maintenance again.
Another mod I did was to install two contactors coming off the battery neg
and positive which is control by a relay from the ignition switch and then
operated the main contactor with the start part of the ignition switch.
When I now the charge the battery pack, I no longer have the charger voltage
going to the motor negative lead which was 70 volts higher than the motor
volt rating which cause these arc over's. The two battery contactors
isolated the charging voltage from the controller and motor.
I place all my batteries, charger, and controller in a insulated container,
the only thing that is AC grounded is the battery charger that is inside a
insulated enclosure, which is then place in a nylon cover foam enclosure.
If everything is very clean, than the tracking or conductance from the
batteries to the frame can be control. Even with my double insulated
system, I may get some tracking across the surface of the epoxy cover
plastic and fiberglass enclosures cause by battery vapors.
I check for this conductance about every month. I then clean the battery
pack every three months to reduce this, but I can still read some tracking
in the 0.1 volt or more from a post of a battery to the battery plastic top.
Roland
----- Original Message -----
From: "Storm Connors" <[EMAIL PROTECTED]>
To: "List EV" <[email protected]>
Sent: Sunday, November 26, 2006 12:47 PM
Subject: Leaking motor
> I am reading 70V between the positive side of my pack and the chassis
> ground. If I remove the negative lead to the motor, there is no voltage
> between the pack and ground. If I close the contactor which is at the
> positive end of the pack, I read 25v from the negative end of the pack to
> the chassis and 50v from the positive end of the pack to chassis.
>
> I assume this is a problem. Am I going to have to go inside the motor to
> find out what is leaking? FWIW, it seems to be running fine. As a Jeep
> owner, I know that is the sure sign of a major problem. Any time it is
> running fine, look out.
>
> Thanks,
> storm
>
>
--- End Message ---
--- Begin Message ---
One of the people in out club, www.TEVA2.com wants to get rid of his battery
heaters. He got them with the truck, which came from Montana, and here in
Tucson we don't really need battery heaters...
He has 24 of the pads (KTA price $15 each) and the Taktronic Control (KTA price
$175)
He also has a Kodiak C-600 controler that for some reason did not work in his
setup. We thought the controller was bad, so we sent it to somebody (forgot his
name) who repairs Kodiak controllers and he said it was fine, put it in his car
and it worked fine, but in John's set-up it didn't, so he got a Curtis and now
wants to get rid of the C-600.
Contact me if you are interested.
info at TEVA2 dot com
Rush
Tucson AZ
www.ironandwood.org
--- End Message ---
--- Begin Message ---
I've seen mention of posting/retrieving files to the Files section on
Yahoo Groups. I tried joining one such group and was denied access.
Fortunately, I found this list via google.
So... about Yahoo... which group is it?
Thanks in advance,
Craig
--- End Message ---
--- Begin Message ---
just to make sure i answer the poll correctly. i have (15) 8v 165Ah
batteries, so that's
120v x 165Ah = 19.8kWh
on the poll is say kW but it really intends kWh, yes?
Osmo S. wrote:
Jack,
check the units in the poll. V x Ah = kWh, not kW.
So your poll is about kWh, which is energy, not capacity. Ah is
capacity. :)
terveisin
Osmo
Jack Murray kirjoitti 21.11.2006 kello 6.51:
Okay, so I add another poll to ask what capacity battery packs are
needed.
http://snappoll.com/poll/148515.php
--- End Message ---
--- Begin Message ---
Tony Hwang wrote:
ev set digest
hehe...only took 5 minutes from joining to realize this is a heavily
used list...just kidding :)
welcome tony. you'll love this list. there are some really, really
smart folks here. do your research, ask the best questions you can,
take your time, and you will definitely learn anything you need to know.
i've learned a ton...though still a noob ;)
kind regards,
mike
--- End Message ---
--- Begin Message ---
Hm. That's a bit bigger than what I have seen on some of the US
Electricars. Hauling two 100lb transformers around is a bit much.
Second option is to just do a 240-208 step down without isolation. I
could do this actually with a 240 volt Variac; just set the dial for
208v and that's that. Oddly enough if I did this and then plugged the
car into 110 volts, would the variac step the voltage down to about 100v?
Chris
Roland Wiench wrote:
Hello Chris,
We normally purchase transformers from a wholesale electrical supply house.
They will be either a Square D, General Electric, Westinghouse. You may have
to go to a electrical shop to get a purchase order to buy from a wholesale
electrical supply company.
If you are isolation for power only, then use a Single Phase - General
Purpose Transformer 3kva 60 Hz Dry Type Metal Clad type rated at 600 volts
and below standard stock transformer with 240/480 primary that have four
taps and a secondary that has 120/240 with four taps.
These are the cheapest type of transformer which will cost about $500.00
You parallel the primary for 240 volts input and series the secondary leads
for a three lead output of 120/240 volts.
Ground only the case of the transformer with the incoming AC ground. You
can develop a separate ground by tapping of the center lead between the two
120 volt coils which is used for ground any of your load devices enclosures
but do not connect this ground to the transformer case.
The closes you can get for a 208 volt output is to use a open type
Industrial Control Dry Transformer in the 3000 VA rating with primary of
208/277 volts and a secondary of 120 volts. Here you input 120 VAC into
the secondary and you come out the secondary at the 208 volt taps. You are
using this type of transformer as a step up type.
If you want a 240 volt input, then you would need two of these transformers
where you series the 120 volts leads of the secondary of both transformer
for a 240 volt input and parallel the primary leads for a 208 volt output.
If you order a custom transformer for 240 primary and a 208 secondary, you
are going to get the same as the above two transformer, except it will be
two coils on one frame.
The normal way we get a 208 volt output, is using three 240 volt primary and
120 volt secondary transformers on a three phase incoming lines connected up
in Delta on the primary and the secondary connected up in wye.
You are best to either used a standard stock 240/480 Primary and 120/240
secondary or special order a 208/277 Primary and a 120 volt secondary which
you input your AC leads into the secondary as a step up.
Don't ask for a isolation transformers, these are special filter units
normally used for communications and electronic systems. These units
normally start at $2500.00 and up.
Roland
----- Original Message -----
From: "Chris Zach" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Saturday, November 25, 2006 9:02 PM
Subject: Need isolation transformer
A question: I need an isolation transformer. 3kw capacity, 240 volts to
208 volts. This is for safety and to step down 240 volts a bit for
faster charging.
Anyone know where might I find one of these? Are they items that can be
found in a local electrician's shop?
Thanks
Chris
--- End Message ---
--- Begin Message ---
> Oddly enough if I did this and then plugged the car into 110 volts,
> would the variac step the voltage down to about 100v?
Absolutely. Most "110V" is now around 120V, so you'd get 104V.
An easier solution yet is to put transformers in anti-series with the
input voltage (speaking for one-phase power). This greatly reduces the
rating, and thus size, needed. My professor once challenged me to
reduce his radio transmitter's input from the modern 120-125V to the
antique 110V for $50 or under. I found four transformers on All
Electronics for $12.50 each, that suited the purpose perfectly.
For your application, assuming you have an imperfect power factor and
need 4kVA, you need to subtract 32VRMS at almost 20ARMS. This is a
transformer rating of just over 600kVA, which isn't tiny but liftable.
Four of Digi-Key's paralleled 237-1282-ND for a total of $163.16 ($40.79
each) would do the job well. They are even in stock. Furthermore, you
could just get two if you needed 224V, or could stay with four and have
an 8kVA output rating. They could be reconfigured still more to work
with a 120V input (each has four windings).
Again, the idea is to put the secondary's "dotted" terminal onto the
primary's "dotted" terminal and then draw from the other two
connections, while the primary is across the line input. This is like
having a 12V and 6V battery, connecting their positive terminals, and
ending up with an imaginary 6V battery across their negative terminals.
- Arthur
On Sun, 2006-11-26 at 17:38 -0500, Chris Zach wrote:
> Hm. That's a bit bigger than what I have seen on some of the US
> Electricars. Hauling two 100lb transformers around is a bit much.
>
> Second option is to just do a 240-208 step down without isolation. I
> could do this actually with a 240 volt Variac; just set the dial for
> 208v and that's that. Oddly enough if I did this and then plugged the
> car into 110 volts, would the variac step the voltage down to about 100v?
>
> Chris
--- End Message ---
--- Begin Message ---
----- Original Message -----
From: "Chris Zach" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Sunday, November 26, 2006 3:38 PM
Subject: Re: Need isolation transformer
> Hm. That's a bit bigger than what I have seen on some of the US
> Electricars. Hauling two 100lb transformers around is a bit much.
>
> Second option is to just do a 240-208 step down without isolation. I
> could do this actually with a 240 volt Variac; just set the dial for
> 208v and that's that. Oddly enough if I did this and then plugged the
> car into 110 volts, would the variac step the voltage down to about 100v?
>
> Chris
>
>
Yes, you can adjust a 240v, 1 phase variac from 0 to 240 volts.
Surplus Sales of Nebraska has them ranging from 1 amp rating at 240 volts to
28 amp at 240 volt.
They also have 1000's of transformers too.
Source: www.surplussales.com
Roland
--- End Message ---
--- Begin Message ---
More knowledgible people than me will probably correct me on this, but I think
if you took a common 115 volt to ~16 volt transformer and wired it up to buck
the 230 voltage you should end up with 208. There's a risk of saturating the
transformer by using it at the higher voltage, but I **think** if you used one
well below its rated capacity you'd be okay. There's usually a variety
available on Ebay for about $30 delivered rated for 20+ amps and weighing about
10 pounds.
Chris Zach <[EMAIL PROTECTED]> wrote: Hm. That's a bit bigger than what I have
seen on some of the US
Electricars. Hauling two 100lb transformers around is a bit much.
Second option is to just do a 240-208 step down without isolation. I
could do this actually with a 240 volt Variac; just set the dial for
208v and that's that. Oddly enough if I did this and then plugged the
car into 110 volts, would the variac step the voltage down to about 100v?
Chris
Roland Wiench wrote:
> Hello Chris,
>
> We normally purchase transformers from a wholesale electrical supply house.
> They will be either a Square D, General Electric, Westinghouse. You may have
> to go to a electrical shop to get a purchase order to buy from a wholesale
> electrical supply company.
>
> If you are isolation for power only, then use a Single Phase - General
> Purpose Transformer 3kva 60 Hz Dry Type Metal Clad type rated at 600 volts
> and below standard stock transformer with 240/480 primary that have four
> taps and a secondary that has 120/240 with four taps.
>
> These are the cheapest type of transformer which will cost about $500.00
>
> You parallel the primary for 240 volts input and series the secondary leads
> for a three lead output of 120/240 volts.
>
> Ground only the case of the transformer with the incoming AC ground. You
> can develop a separate ground by tapping of the center lead between the two
> 120 volt coils which is used for ground any of your load devices enclosures
> but do not connect this ground to the transformer case.
>
> The closes you can get for a 208 volt output is to use a open type
> Industrial Control Dry Transformer in the 3000 VA rating with primary of
> 208/277 volts and a secondary of 120 volts. Here you input 120 VAC into
> the secondary and you come out the secondary at the 208 volt taps. You are
> using this type of transformer as a step up type.
>
> If you want a 240 volt input, then you would need two of these transformers
> where you series the 120 volts leads of the secondary of both transformer
> for a 240 volt input and parallel the primary leads for a 208 volt output.
>
> If you order a custom transformer for 240 primary and a 208 secondary, you
> are going to get the same as the above two transformer, except it will be
> two coils on one frame.
>
> The normal way we get a 208 volt output, is using three 240 volt primary and
> 120 volt secondary transformers on a three phase incoming lines connected up
> in Delta on the primary and the secondary connected up in wye.
>
> You are best to either used a standard stock 240/480 Primary and 120/240
> secondary or special order a 208/277 Primary and a 120 volt secondary which
> you input your AC leads into the secondary as a step up.
>
> Don't ask for a isolation transformers, these are special filter units
> normally used for communications and electronic systems. These units
> normally start at $2500.00 and up.
>
> Roland
>
>
> ----- Original Message -----
> From: "Chris Zach"
> To:
> Sent: Saturday, November 25, 2006 9:02 PM
> Subject: Need isolation transformer
>
>
>> A question: I need an isolation transformer. 3kw capacity, 240 volts to
>> 208 volts. This is for safety and to step down 240 volts a bit for
>> faster charging.
>>
>> Anyone know where might I find one of these? Are they items that can be
>> found in a local electrician's shop?
>>
>> Thanks
>> Chris
>>
>>
>
---------------------------------
Cheap Talk? Check out Yahoo! Messenger's low PC-to-Phone call rates.
--- End Message ---
--- Begin Message ---
Some time back Ray Wong wrote a nice review of Microchip's PICdem Motor Control
Board. I forwarded Ray's message to the appropriate manager with the
suggestion that it be made available to EV lister's at a discount. He agreed
and added it to Microchip's Holiday Tools sale. So from now until the end of
the year it's 20% off list price. See
www.microchip.com/express<http://www.microchip.com/express> for more details on
how to get the discount and other tools included in the sale.
Full disclosure - I work for Microchip but I don't speak for them. I just know
who to talk to about things as this!
Danno (Also interested in an Open Controller based on MCHP parts, of course)
-------------------------------------------------------------------------------------------------
Ray said:
Message-ID: <[EMAIL PROTECTED]>
Date: Fri, 3 Nov 2006 23:23:06 -0800 (PST)
From: Ray Wong <[EMAIL
PROTECTED]<http://by115fd.bay115.hotmail.msn.com/cgi-bin/compose?curmbox=00000000-0000-0000-0000-000000000001&a=7168cedfd05f32f48f7c8980d50f82d981aa7ee95115899bf8bc323a48660299&mailto=1&[EMAIL
PROTECTED]&msg=805DE0FC-1D7A-47BC-8176-8941BD91C2A8&start=0&len=55507&src=&type=x>>
Subject: Re: EV controllers? the 4th option...
To:
[email protected]<http://by115fd.bay115.hotmail.msn.com/cgi-bin/compose?curmbox=00000000-0000-0000-0000-000000000001&a=7168cedfd05f32f48f7c8980d50f82d981aa7ee95115899bf8bc323a48660299&mailto=1&[EMAIL
PROTECTED]&msg=805DE0FC-1D7A-47BC-8176-8941BD91C2A8&start=0&len=55507&src=&type=x>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Transfer-Encoding: 8bit
Content-Disposition: inline
I have been lurking while following this discussion on building a controller
using Microchips . At the same time I am working on the bench with one of these
Microchip PICDEM Motor Control Development Boards (PIC18F4431), so I have a
little prespective on this topic.
It took all of 5 minutes to get this board up and running. It will take DC
from 100V to 350V and AC up to 270V and even has a voltage doubler.
The board is well isolated with optos and linear optos It is set up for three
isolated phase current monitors. It has inputs for hall sensor for BLDC. It
has the circuitry for sensorless BLDC including opto isolation.
The board has a speed pot, start button. reverse button, reset button, and 5
LEDs
The board is set up for an optional LIN bus. The LIN bus is well suited for
automotive applications and can be a sub-network for a CANbus interface.
The inverter power module IR IRAMS10UP60A can only handle a small motor but is
good for testing. The module is used in some home appliances with up to 1/2 hp
motors.
The board has an RS232 port to connect to your computer. It has a Graphic
User Interface (GUI) that will allow you to set most motor parameters and
monitor everthing from rpm, voltage, phase current, temp.
The board has an ICD connector RJ-11 to allow connection to MPLAB ICD2
programming and in circuit debugging.
The board comes with two Microchips, a PIC18F4431 with BLDC firmware and a
second PIC set up for three phase ACIM. The board has I/O pinouts right at the
microchip to allow easy connection via ribbon cable to a breadboard or daughter
board.
Clearly, this is not a production board. It does however, give me a much
quicker learn time. I can test things on the board at low power and then add
higher power components and finally take the design to a custom made board. The
board has an open design and the basic software is already working for BLDC,
single phase ACIM, 3 phase ACIM.
I bought this board primarily to learn about BLDC and ACIM controllers. It
could be used to prototype a series DC or a SEPEX controller. Time permitting,
I personally would like to build a high power sepex controller. My two
Prestolite 4001 sepex motors are still sitting.
Microchip has several application notes to help learn about motor control
design using this microchip.
There are probably others on the list that want to learn about motor
controllers. This board is probably not a bad starting point.
Imagine what could be developed if many people on the list were working on
motor controller designs, especially if we adopted some standards.
EZESPORT
--- End Message ---
--- Begin Message ---
I went on a 20 mile bike ride today on a scenic route
that is a bike path that parallels the Ohio canal boat
route that was the main transport route for goods
during the 1800's. I passed 2 physically able guys
riding Segways down the path. It was cool seeing the
EV's, but I wondered why they were riding on this
pedestrian/bike path. EV's are nice transport, but I
wonder why they were riding on a bike path? Perhaps 2
guys with a really cool toy.
Rod
W8RNH
--- End Message ---
--- Begin Message ---
At 03:32 PM 26/11/06 -0800, Steve wrote:
More knowledgible people than me will probably correct me on this, but I
think if you took a common 115 volt to ~16 volt transformer and wired it
up to buck the 230 voltage you should end up with 208. There's a risk of
saturating the transformer by using it at the higher voltage, but I
**think** if you used one well below its rated capacity you'd be
okay. There's usually a variety available on Ebay for about $30 delivered
rated for 20+ amps and weighing about 10 pounds.
G'day Steve, and all
If you take a 115V transformer and hook it up to 230V you will let the
magic smoke out. The upper limit of a transformer is the turns ratio to the
core area, i.e. for a given core size you need (x) turns per volt (or volts
per turn on big transformers). A 115V transformer will need twice as many
turns to work on 230V, but a transformer with twice the core area will
probably only have the number of turns the smaller 115V one has to work on
230V.
To buck the voltage (or boost) you need to connect as follows (view with
fixed-width font) - be aware this is not isolated:
______
| |
230V line1----@|| |
@||@-
@||@
230VAC @||@ 22VAC
@||@
@||@--------
230V line2----@|| 208VAC
|_____________
If you connect the secondary to boost, you'd have 252VAC. To change from
buck to boost is reversing the connections on the secondary OR the primary
of the transformer.
Now here is the main benefit for mobile use: The size of the transformer is
only for the current in the secondary, i.e. if you are needing 25A then the
transformer only needs to be 22V x 25A = 550VA, if you were to use an
isolation transformer to get 208V @ 25A you'd need a 5200VA transformer -
around ten times the weight!
In reality the harmonics that are caused by pulling the current in a peak
at the top of the voltage wave when driving a rectifier means that a
transformer needs to be about 30% oversize.
The same method works to create a "bad-boy with manners" to trim voltages
to keep the current and voltage in the desired limits. The hard part of
such a charger is the brains needed to make it work.
Hope this helps
Regards
[Technik] James
--- End Message ---
--- Begin Message ---
I'm currently using the PicDem and other tools on my 3
phase BLDC control. This is a nice DSP that can also
be used for 3 phase inverter controls. Minor code
changes will make it a series brush control or
H-bridge directional control. Our Microchip app
engineer previously worked for my company,
Ametek-Rotron, so support is quite knowledgeable.
Rod
W8RNH
--- Danno none <[EMAIL PROTECTED]> wrote:
> Some time back Ray Wong wrote a nice review of
> Microchip's PICdem Motor Control Board. I forwarded
> Ray's message to the appropriate manager with the
> suggestion that it be made available to EV lister's
> at a discount. He agreed and added it to
> Microchip's Holiday Tools sale. So from now until
> the end of the year it's 20% off list price. See
>
www.microchip.com/express<http://www.microchip.com/express>
> for more details on how to get the discount and
> other tools included in the sale.
>
> Full disclosure - I work for Microchip but I don't
> speak for them. I just know who to talk to about
> things as this!
>
> Danno (Also interested in an Open Controller based
> on MCHP parts, of course)
>
>
-------------------------------------------------------------------------------------------------
> Ray said:
>
> Message-ID:
>
<[EMAIL PROTECTED]>
> Date: Fri, 3 Nov 2006 23:23:06 -0800 (PST)
> From: Ray Wong
>
<[EMAIL
PROTECTED]<http://by115fd.bay115.hotmail.msn.com/cgi-bin/compose?curmbox=00000000-0000-0000-0000-000000000001&a=7168cedfd05f32f48f7c8980d50f82d981aa7ee95115899bf8bc323a48660299&mailto=1&[EMAIL
PROTECTED]&msg=805DE0FC-1D7A-47BC-8176-8941BD91C2A8&start=0&len=55507&src=&type=x>>
> Subject: Re: EV controllers? the 4th option...
> To:
>
[email protected]<http://by115fd.bay115.hotmail.msn.com/cgi-bin/compose?curmbox=00000000-0000-0000-0000-000000000001&a=7168cedfd05f32f48f7c8980d50f82d981aa7ee95115899bf8bc323a48660299&mailto=1&[EMAIL
PROTECTED]&msg=805DE0FC-1D7A-47BC-8176-8941BD91C2A8&start=0&len=55507&src=&type=x>
> MIME-Version: 1.0
> Content-Type: text/plain; charset=iso-8859-1
> Content-Transfer-Encoding: 8bit
> Content-Disposition: inline
>
> I have been lurking while following this discussion
> on building a controller
> using Microchips . At the same time I am working on
> the bench with one of these
> Microchip PICDEM Motor Control Development Boards
> (PIC18F4431), so I have a
> little prespective on this topic.
>
> It took all of 5 minutes to get this board up and
> running. It will take DC
> from 100V to 350V and AC up to 270V and even has a
> voltage doubler.
>
> The board is well isolated with optos and linear
> optos It is set up for three
> isolated phase current monitors. It has inputs for
> hall sensor for BLDC. It
> has the circuitry for sensorless BLDC including opto
> isolation.
>
> The board has a speed pot, start button. reverse
> button, reset button, and 5
> LEDs
>
> The board is set up for an optional LIN bus. The
> LIN bus is well suited for
> automotive applications and can be a sub-network for
> a CANbus interface.
>
> The inverter power module IR IRAMS10UP60A can only
> handle a small motor but is
> good for testing. The module is used in some home
> appliances with up to 1/2 hp
> motors.
>
> The board has an RS232 port to connect to your
> computer. It has a Graphic
> User Interface (GUI) that will allow you to set most
> motor parameters and
> monitor everthing from rpm, voltage, phase current,
> temp.
>
> The board has an ICD connector RJ-11 to allow
> connection to MPLAB ICD2
> programming and in circuit debugging.
>
> The board comes with two Microchips, a PIC18F4431
> with BLDC firmware and a
> second PIC set up for three phase ACIM. The board
> has I/O pinouts right at the
> microchip to allow easy connection via ribbon cable
> to a breadboard or daughter
> board.
>
> Clearly, this is not a production board. It does
> however, give me a much
> quicker learn time. I can test things on the board
> at low power and then add
> higher power components and finally take the design
> to a custom made board. The
> board has an open design and the basic software is
> already working for BLDC,
> single phase ACIM, 3 phase ACIM.
>
> I bought this board primarily to learn about BLDC
> and ACIM controllers. It
> could be used to prototype a series DC or a SEPEX
> controller. Time permitting,
> I personally would like to build a high power sepex
> controller. My two
> Prestolite 4001 sepex motors are still sitting.
>
> Microchip has several application notes to help
> learn about motor control
> design using this microchip.
>
> There are probably others on the list that want to
> learn about motor
> controllers. This board is probably not a bad
> starting point.
>
> Imagine what could be developed if many people on
> the list were working on
> motor controller designs, especially if we adopted
> some standards.
>
> EZESPORT
>
>
--- End Message ---
