EV Digest 4314
Topics covered in this issue include:
1) RE: Contactor controller, Was:RE: Mechanical PWM Controllers
by "Stu and Jan" <[EMAIL PROTECTED]>
2) Curtis 1204 has almost beaten me.
by "Stu and Jan" <[EMAIL PROTECTED]>
3) Re: Got my taperlock hub off!
by Electro Automotive <[EMAIL PROTECTED]>
4) Re: Curtis 1204 has almost beaten me.
by Ryan Stotts <[EMAIL PROTECTED]>
5) One step up from AGMs?
by "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
6) Re: Contactor controller, Was:RE: Mechanical PWM Controllers
by Lee Hart <[EMAIL PROTECTED]>
7) Uh,
what's *3/4 OF AN INCH* among friends?? (was: Re: Pics of the Big
Guy...)
by "Christopher Robison" <[EMAIL PROTECTED]>
8) Re: Trains an' Stuff
by Lee Hart <[EMAIL PROTECTED]>
9) RE: Curtis 1204 has almost beaten me.
by "Stu and Jan" <[EMAIL PROTECTED]>
10) Re: Treadmill motor that could be used for EV accesory power
by "Peter VanDerWal" <[EMAIL PROTECTED]>
11) Re: Treadmill motor that could be used for EV accesory power
by "Peter VanDerWal" <[EMAIL PROTECTED]>
12) RE: Contactor controller, Was:RE: Mechanical PWM Controllers
by James Massey <[EMAIL PROTECTED]>
13) RE: Trains an' Stuff
by "djsharpe" <[EMAIL PROTECTED]>
14) RE: Contactor controller, Was:RE: Mechanical PWM Controllers
by "djsharpe" <[EMAIL PROTECTED]>
15) Re: Mechanical PWM Controllers
by James Massey <[EMAIL PROTECTED]>
16) Re: pedal generator
by keith vansickle <[EMAIL PROTECTED]>
17) Curtis dc/dc converter
by "ohnojoe" <[EMAIL PROTECTED]>
18) Re: Trains an' Stuff
by Steve Gaarder <[EMAIL PROTECTED]>
19) FW: Contactor controller, Was:RE: Mechanical PWM Controllers
by "Stu or Jan" <[EMAIL PROTECTED]>
--- Begin Message ---
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Lee Hart
Sent: Monday, April 25, 2005 4:44 PM
To: [email protected]
Subject: Re: Contactor controller, Was:RE: Mechanical PWM Controllers
Stu and Jan wrote:
> Assuming I switch from 0 to: 12, 24, 36, and 48 V, is an additional
> first step with a resistor required for a soft start?
Yes. Assume you are using a series DC motor.
In fact, my motor is an Imperial PM motor produced for floor scrubbers.
Does a PM motor suck amps at start?
I am building a 200 lb. trike hybrid. A 6.5 hp B&S for one rear 12.5"
scooter wheel and the motor for the other.
It will have a leaning front end with independent (foot) steering.
BoyntonStu
--- End Message ---
--- Begin Message ---
I am very frustrated in trying to get this semiconductor brick to act like a
controller.
The only thing that I don't have that I see in the Manual is a 250 ohm
resistor across the main switch.
Is there a starting procedure that I am not doing right?
This is what I have tried:
Send 48 Volts to the key terminal.
Adjust the pot to almost zero ohms.
Switch the battery on.
Turn up the pot.
NO JOY!
Hints/helps/suggestions pretty please.
Boyntonstu
--- End Message ---
--- Begin Message ---
Mike - is there some reason you can't put in two or three tapped holes in
these hubs ( at, for example, the same diameter as the pull-in screws) so
screws can be used to force the hub apart from the bushing. Is there a
flat surface on the bushing for these screws to push against? This way,
there would be no load on the motor shaft or bearings at all when taking
the hub off.
There's very little room in the hubs. Sometimes it's hard enough just
fitting in the holes for the pull-in screws.
I know you've been doing this for a while, and it sounds like most of the
time, you have no problems getting these things apart, but I would be
nervous hammering either the pull-in screws or the end of the puller.
Either could damage the motor bearings.
Ball bearings ( inlike the bearings in most ICE engines) are not very
tolerant of impact loads, and the damage to the bearings may not be
obvious right away, but still cause a failure later on.
It usually just takes one sharp rap with about a 1 lb. hammer. I have
never seen a bearing failure in one of these motors.
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 ---
Stu and Jan wrote:
> Is there a starting procedure that I am not doing right?
Are you using one of these for the potbox?
http://www.electroauto.com/catalog/potbox.shtml
How about that "feature" that won't let the controller turn on if the
pot box is not all the way in the off position?
--- End Message ---
--- Begin Message ---
What battery chemistries are available now with Energy density and price
between PbSO4 and Li-Ion? That is, who is currently selling what?
BTW, I spoke with an Evercel person today. They said Evercel is not producing
any NiZN batts now but will decide within 90 days if they will restart
production. They also say nobody else is producing rechargable NiZn batts.
I've also browsed SAFT site -- haven't called for prices and availability yet.
What other options are there?
Mark Freidberg
OEVA member in Portland, Oregon.
______________________________________________________________________
Speed up your surfing with NetZero HiSpeed.
Now includes pop-up blocker!
Only $14.95/month -visit http://www.netzero.com/surf to sign up today!
--- End Message ---
--- Begin Message ---
Stu and Jan wrote:
> In fact, my motor is an Imperial PM motor produced for floor
> scrubbers. Does a PM motor suck amps at start?
A PM motor is even "jerkier" than a series motor with fixed-voltage
steps and no starting resistor. A series motor has a range of speeds for
a given applied voltage. As the load increases, it slows down. A PM
motor tries to run at constant speed for a given applied voltage.
--
"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 ---
Ugghhh ... I have some corrections to make -- it seems I've been VERY
wrong about probably the most critical imaginable component of this
discussion. Details below.
Seth Allen said:
> Ok. I am familiar with end yokes and slip joints, not slip yokes.
>
> You need to define a few more things:
>
> How many times are you going to hit a contactor bypass torque of 1300
> ft-lb? The fatigue equations I am using so far are based on infinite
> life. And for some reason I seemed to be using 1600 ft-lbs based on
> your speculation?
Good point. I've been ignorantly thinking in terms of being able to
handle "maximum torque" without considering the frequency of time spent in
that operating area. Its safe to say I'd hit whatever maximum torque the
motor can dish out a few times a year as I go to races. As I've been
accused of here in the past I'm a bit of a leadfoot on the street, but I'm
not a maniac.
1600 ft-lbs is a figure born mostly of uncertainty. I don't have good
data. All I can do is project based on the figures I have which were taken
with fewer amps going through a shorter version of the motor. 1300-1400
ft-lbs seems reasonable, 1600 seemed "safe" as I don't really know how
much extra torque that 4 additional inches of motor length and 1000-1100
extra amps beyond the dyno test conditions are going to get me.
But yes, actually hitting that button would be pretty rare, and most of
the time I'd drive the zilla detuned for efficiency and battery
preservation.
> If we assume 1100 ft-lb for infinite life (street use) then that is a
> different picture.
This seems pretty reasonable.
> 1600 ft-lb on a minor diameter of 1.625 (and no
> stress concentration factor) at infinite life is about a unity factor
> of safety. That is the dragstrip torque, not a street torque. But with
> derating for street usage. Which means things look pretty good with
> something like 4140.
>
> Not knowing your spline size
Ah, spline size. Or, more specifically, shaft size. Here is where I
*really* screwed up.
Unsuccessful in trying to find the email or document where I came up with
the size of the shaft, I confirmed with Netgain today. Turns out, the
shaft is in fact 2" to begin with, but the part that's outside the motor
is much smaller, due to the size of the bearing they're using. It's 1.25"
in diameter as it exits the motor. Needless to say, this changes
everything.
I'm going to see if I can get them to change to a 1 3/8" ID bearing, which
on the surface seems doable, as this would make their shaft the same size
as the output shaft of a Lenco transmission. Of course this would also
mean I'd need to use a simlar chrome-moly steel, which will be more
expensive. Hopefully Netgain won't even have to modify the rest of the
motor, if they can find a bearing with the same outer diameter as the ones
they're now using.
At any rate, about one thing I now feel pretty confident - I believe this
motor has far more potential than it can actually realize as it is
currently being constructed. It needs More Shaft.
> and not knowing the effect of the slip
> joint means I have to stop here until you decide on a spline. It also
My recently-corrected understanding is that you generally want to shoot
for as short a shaft as possible. The guy at Lenco I talked to says they
typically make their output shafts 3 inches long, with 2 inches of
connection with the slip yoke to provide a remaining maximum of 1 inch of
travel. 4 inches is also reasonable, and although they can make the shaft
up to 6 inches long they recommend keeping it short. This is especially
important at higher RPMS.
> may be that you need to harden the armature just to make a good slip
> joint surface. But I don't know about that.
This is what I was thinking about when I brought up cryo-hardening. Doing
that, or plating or nitriding might help increase abrasion resistance, but
assuming the connection is well-greased I'm not sure how important that
will be. On the strip I'm thinking suspension travel will be limited, and
on the street I won't be pulling 2500A. I think I'm going to skip such
measures unless someone has applicable experience to recommend it.
...Tomorrow, I talk to Netgain about motor bearings.
--chris
>
>
> On Apr 23, 2005, at 2:21 AM, Christopher Robison wrote:
>
>> Seth Allen said:
>>> Ok, before I start, I will make a few assumptions and such:
>>>
>>> 1: You don't want to greatly increase cost, so a material that doesn't
>>> need a rough machining, heat treat and grind to size is desirable
>>
>> I agree with this (I've got plenty of other parts of the truck that are
>> also demanding my money), though I'm not sure even what kind of
>> neighborhood to shoot for. Am I looking at a thousand bucks no matter
>> what
>> I do, or am I just trying to save a hundred or so? I've already spent
>> a
>> few grand; a couple hundred well-placed dollars aren't so much of an
>> issue, but adding half the cost of the motor would be difficult.
>>
>>
>>> 2: You need some plunge on the output
>>
>> I'm not sure what this means. Are you referring to the need for a slip
>> yoke, or sliding element somewhere along the driveline? If so, yes --
>> I am
>> not willing to lock down the rear end (at least not permanently); I
>> need
>> to allow for some suspension travel.
>>
>>> 3: a standard interface is nice
>>
>> I have bought from Inland Empire in the past; they make a wide variety
>> of
>> slip yokes. In general though, yes, standard == good.
>>
>>> 4: you want it sized for fatigue life at peak torque (many dragstrip
>>> runs)
>>
>> Agreed. The motor will be heavy and expensive to ship, making the cost
>> of
>> replacing the shaft pretty high, if I'm to have Netgain doing it.
>> Warfield
>> has a location in Dallas I'm told, but they don't work on the Warps.
>> All
>> in all, I'd like the shaft to last. :o) I'm willing to spend a little
>> more now to help with this.
>>
>>> 5: you will not be getting it plated
>>
>> I can't say without more information. What would be the benefit of
>> plating, and with what material? Is it expensive? Would it be worth
>> it? If
>> you're talking about aesthetics (chrome plating or whatever), then no.
>> I
>> just don't want it rusting. :o)
>>
>>
>>> If all this is right, then a suggestion for a steel might be a
>>> pre-hardened AISI 4140 which is fairly common and fairly easy to
>>> machine. It won't be fully hard, but you won't have to do the heat
>>> treat and grind to size.
>>
>> I will make a note of this -- thank you!
>>
>>
>>> As for an output. I have done standard yokes with slip joint
>>> driveshafts for trucks. Not sexy, but they work. But your torque is
>>> actually quite low if this is direct drive to the rear diff.
>>
>> Compared to the potential if I had a transmission, yes, the torque is
>> pretty low. It seemed high to me, but that was during my search for a
>> suitable manual transmission. On the other hand, the existing
>> driveshaft
>> on my truck probably doesn't even see a third as much torque, flooring
>> it
>> in first gear. The input shaft on my transmission is only rated for 175
>> ft-lbs; I don't have the ratios handy but output torque can't be too
>> spectacular. In fact, in 1st I guess I probably get less peak torque at
>> the *wheels* today than I'll eventually get out of this motor. In that
>> sense, it's not so bad. :o)
>>
>>> A CV joint
>>> can easily handle this torque and requires no alignment of the yokes
>>> or
>>> concern over driveshaft angle. A CV flange on the output of the motor
>>> with whay would normally be an IRS halfshaft could work quite well.
>>
>> I am not quite familiar with the setup you're referring to. Is it
>> possible
>> to get something like this that is long enough, and lightweight? I
>> have
>> been assuming the need for a traditional driveshaft and a slip-yoke on
>> the
>> motor, in part because of the arrangement of the motor and
>> differential.
>> I'm planning on putting the motor under the passenger compartment,
>> between
>> the seats, where the transmission is now. I would put it further back,
>> but
>> I'd like to put battery boxes between the frame rails. I've been
>> planning
>> on using a large diameter aluminum or carbon fiber shaft between the
>> battery boxes to reduce spinning mass. Can I have this same arrangement
>> with CV joints?
>>
>> When you speak of CV joints, I'm imagining the three rollers at the
>> end of
>> a shaft which fits in a cup with three deep corresponding grooves,
>> allowing both the CV torque transfer as well as a small amount of
>> sliding
>> motion. Is this the sort of thing you're referring to?
>>
>>> It
>>> is what I would do, but some people really refer U-joints.
>>
>> At this point, I don't think I have enough knowledge to have a valid
>> preference. I have come to certain conclusions based on what I've
>> learned
>> so far, but of course nothing is really concluded until I start
>> actually
>> acquiring the parts. Until then, the more I can learn, the better. I'm
>> OK
>> with CV joints (actually, I like the idea of the smooth torque
>> transfer,
>> and not having to worry about matching angles and such), I just don't
>> know
>> what else about my driveline plans would have to change.
>>
>>> If that is
>>> the case, then at www.roadranger.com there are loads of U-joint specs
>>> there. ANd they will specify the spline options. Let me know what your
>>> preference is (CV joint or U-joint) and we can wade through the
>>> options
>>> and once a spline is found, see if it will work. Your torque is so low
>>> that with half-hard 4140 and an easily cut involute spline on a ~2"
>>> diameter that I think there will be no problem with fatigue life, even
>>> after effects like corrosion are figured in.
>>
>> What are the corrosion properties of 4140? What kind of degradation
>> can I
>> expect, mechanically and aesthetically, assuming this will be
>> subjected to
>> water and road grime? For the most part though, this sounds like what
>> I'm
>> looking for. Can we say that 1144 is out of the picture? I understand
>> it
>> responds well to heat treating, though I don't know if this will give
>> me
>> what I want.
>>
>> I will see what info I can dig up on CV joints used in this
>> application.
>> Although I'm hesitant about using techniques that aren't popular in
>> racing, I realize the operating parameters here are a bit different and
>> may call for an unusual solution. Mainly, if we can plan a driveline
>> that's lightweight, can span from the cab to the differential, can
>> tolerate the torque and the RPM (I'll be running a 5.0-5.3 or so rear
>> end
>> ratio, not quite sure yet), then I won't have much rational cause to
>> disagree.
>>
>> --chris
>>
>
>
--- End Message ---
--- Begin Message ---
Evan Tuer wrote:
> > is there a really GOOD argument for 25hz, today?
Yes. At 25 Hz, your motors and transformers will be heavier (weight is
proportional to frequency), but your laminations can be very thick
slabs. Much easier to deal with when making truly large equipment. Also,
weight is not a liability in a stationary power plant, or in a railroad
engine.
> I recently had a trip on the Flam railway, which runs up the side
> of a very picturesque fjord in Norway... 16 and 2/3rd Hz!?
Below 15-20 Hz, you don't need laminations at all. This frequency was
picked very long ago, in the 1800s, because you could just use solid
cast iron for the rotors and stators.
--
"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 ---
I am using a 10k Radio Shack potentiometer as described in the Curtis
Manual.
Are you saying that it needs a little resistance to 'turn on'?
Thanks for your suggestion.
Boyntonstu
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Ryan Stotts
Sent: Monday, April 25, 2005 11:25 PM
To: [email protected]
Subject: Re: Curtis 1204 has almost beaten me.
Stu and Jan wrote:
> Is there a starting procedure that I am not doing right?
Are you using one of these for the potbox?
http://www.electroauto.com/catalog/potbox.shtml
How about that "feature" that won't let the controller turn on if the
pot box is not all the way in the off position?
--- End Message ---
--- Begin Message ---
The point was not just the size in inches, but also the weight. Given the
size and the strength of the rare earth magnets, the requirements for iron
for good magnetic coupling and the applied torque, you end up with a
fairly heavy generator. At a guess 25-30 lbs or more.
I've seen results of efficiency tests for several of these homemade
generators, I haven't seen one yet that is better than 75%.
Much better, in my opinion, to use a high efficiency motor, like one from
ecycle.com (96%+), and a single stage chain/belt increaser (97-98%
efficient). Total would be 94%-95% efficient, weight would be approx
13lbs (not counting crank arms and pedals).
They make brushless windmill alternators that are even lighter (the ecycle
motor is more powerfull than necessary) with similar efficiency, no idea
what they cost though.
> --- Peter VanDerWal <[EMAIL PROTECTED]> wrote:
>> Yes it is possible to build a generator that will
>> work at 70-80 RPM,
>> unfortunately it would be huge. In order to get the
>> necessary number of
>> poles and fast enough speed at the coils, it woul
>> probably need to be
>> approx 2 feet in diameter
>
> actually 2 feet is not that large. if you have a bike
> or exercycle. place the balls of your feet on the
> pedals now hove another person measure from the heel
> of the shoe farthest from the center to the toe of the
> other and you will find the the circle thus defined is
> something like 27" in diameter therefore a 2 ft dia is
> smaller than what is normally created by anyone who
> pedals a bike. it is just that the normal (verticle)
> orientation of the pedals establishes an elipse with a
> 27 in long axis and a 14 in verticle. If you are
> building a generator you can use a dia of up to 36 in
> and still not interfere pedaling. so just do the
> electric stuff and i will do the mechanical stuff to
> build one and see what can be generated. i have read
> some about the water and air generators on the
> internet(hugh piggot etc) but the things they come up
> with are primitive looking and heavy. (based on disk
> brake components) compared to the motors i have taken
> apart where the windings are complex and overlapping
> these brake drum/rotor generators seem not to be very
> sophisticated. I just want to know how many magnets
> and windings (and how to hook up the wires from the
> windings--delta or three phase or ?) i need to make
> generator that wil put out 12-36 volts as many amps as
> possible with my trired old legs???
>>
>> It's better (in my opinion) to use a generator that
>> will work with a
>> single stage speed increaser. Something like a 5:1
>> ratio. Assuming an
>> 80-90 RPM pedal speed, this works out to about
>> 400-450 rpm. This is
>> doable with generators designed for windmills.
>>
>>
>> > peter,
>> > As you suggest in a personal low speed light
>> weight ev
>> > designed for either commuting of touring every
>> little
>> > bit helps. With a designed for human power
>> generator
>> > even if it is only 75 watts constant that off sets
>> how
>> > much battery energy you require to accomplish your
>> > goal of distance. The problem is there are no
>> > specifically designed for human power generators.
>> all
>> > the ones I have found are not really designed to
>> make
>> > elecrticity at 60-70 rpm which is what one can
>> > constantly pedal. instead the generators i have
>> found
>> > take the slow speed human energy and dilute it by
>> > mechanical means to go faster. in other words the
>> > generators are designed to produce power at high
>> rpms
>> > and the mechanical/friction losses use up much of
>> the
>> > human power. Is there no way to make a perm mag
>> > generator that will have the correct number of
>> poles
>> > and windings to generate electricity at 60 rpm? I
>> > don't know much about electricity but maybe there
>> is
>> > someone on the list who does and can explain this
>> to
>> > me
>> >
>> > thanks
>> > keith
>> > --- Peter VanDerWal <[EMAIL PROTECTED]> wrote:
>> >
>> >> > With a more efficient generator, I am sure that
>> >> you could charge up a
>> >> > personal electric vehicle of some sort.
>> Perhaps
>> >> an electric bicycle.
>> >
>> >>
>> >> With an efficient enough pedal powered generator,
>> >> personal EVs have some
>> >> advantages. Keeping your workout at a constant
>> level
>> >> regardless of terain
>> >> or traffic for example, or energy banking at
>> stops.
>> >
>> >
>> >
>> >
>> > __________________________________
>> > Do you Yahoo!?
>> > Yahoo! Small Business - Try our new resources
>> site!
>> > http://smallbusiness.yahoo.com/resources/
>> >
>> >
>>
>>
>
> __________________________________________________
> Do You Yahoo!?
> Tired of spam? Yahoo! Mail has the best spam protection around
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>
>
--- End Message ---
--- Begin Message ---
> Also if you are handy I would advise looking into DIY Dual Disc Axial Flux
> low speed alternators. Google on Hugh Piggot, he wrote a few books on
> building these. www.scoraigwind.com . Edwin Lenz also has a good DDAF
> alternator site www.windstuffnow.com
While these are good enough generators for wind turbines (due to the low
cost), IMHO they are not good for pedal generators.
I've seen a few efficiency plots posted to the web, these generators tend
to be around 60-70% efficient.
I think you good do MUCH better using a good quality PM motor and a single
or double stage step-up.
The main disadvantage to using a chain or belt drive rpm increaser on a
wind turbine is the fact that they require periodic maintenance (somewhat
difficult to accomplish 50 feet up in the air). This is not so much of a
disadvantage on a pedal generator.
--- End Message ---
--- Begin Message ---
At 10:10 AM 25/04/05 -0400, Stu wrote:
James,
The picture is becoming clearer thanks to you.
You're welcome
On start up, the idea is to have a soft start to prevent an uncomfortable
lurch.
Correct
In your example, you calculated the current at 48 Volts and it came out to
be 320 Amps or 4 times the rated current of my motor at 36 Volts.
If, instead of 48Volts we switched only 12 Volts in, the current would be 80
Amps as well.
The question therefore remains:
Assuming I switch from 0 to: 12, 24, 36, and 48 V, is an additional first
step with a resistor required for a soft start?
The definitive answer is: It depends! Without knowing the *actual*
resistance of your motor, I'd be guessing. But I'd suspect that the actual
resistance is lower than I was using for the calculation. But you could use
12V+resistor as first step (instead of a higher voltage as in the previous
example), which would significantly reduce the power dissapation of the
resistor.
You stated in another post that you are using a permanent magnet motor.
This is like a shunt motor, but you can't weaken the field to get smoother
control, so (as Lee indicated) it tries very hard to run at a speed that is
effectively commanded by the voltage applied.
Unless you can get the contactors cheaply (ie wrecked forklifts etc) I'd be
getting a controller such as those made by 4QD in the UK (who may have a
controller kit available to reduce your cost and make it a service-yourself
unit), or a golf cart controller. You could also try your local forklift
service companies, there may be a complete 48V traction control panel
available from a wrecked pallet truck or similar.
Hope this helps
James
--- End Message ---
--- Begin Message ---
We had 25Hz in Melbourne Australia on the railways. It was used to run
the rotary converter stations that produced 1500V for the sparkies (elec
trains). My understanding was that there was a limit with commutation-go
too far and you get a flashover- with the early DC generators and the
slower speeds of the 25Hz synch motors helped get around it. This is
different from the 16 2/3 Hz train motors described which run directly
from the AC where low speeds were needed for the haulage. By now all
converter stations will have gone to Silicon some having also had glass
mercury arc "octopus" rectifiers on the way. A spine chilling experience
was to have been in a converter station when the gigantic octopus
suddenly illuminated their satanic violet glow & hummed loudly with
2000A when trains entered the traction sector.
David Sharpe (Elec Engineer)
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Lee Hart
Sent: Tuesday, 26 April 2005 12:32 PM
To: [email protected]
Subject: Re: Trains an' Stuff
Evan Tuer wrote:
> > is there a really GOOD argument for 25hz, today?
Yes. At 25 Hz, your motors and transformers will be heavier (weight is
proportional to frequency), but your laminations can be very thick
slabs. Much easier to deal with when making truly large equipment. Also,
weight is not a liability in a stationary power plant, or in a railroad
engine.
> I recently had a trip on the Flam railway, which runs up the side
> of a very picturesque fjord in Norway... 16 and 2/3rd Hz!?
Below 15-20 Hz, you don't need laminations at all. This frequency was
picked very long ago, in the 1800s, because you could just use solid
cast iron for the rotors and stators.
--
"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 ---
You cannot use 36V as part of the battery would be unusable to get it
unless you switch 12 12V batteries. First step 12x12V second 6 as 24V
third 4 as 36V fourth 3 as 48V. Lots of contactors!
David
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of James Massey
Sent: Tuesday, 26 April 2005 7:02 PM
To: [email protected]
Subject: RE: Contactor controller, Was:RE: Mechanical PWM Controllers
At 10:10 AM 25/04/05 -0400, Stu wrote:
>James,
>
>The picture is becoming clearer thanks to you.
You're welcome
>On start up, the idea is to have a soft start to prevent an
uncomfortable
>lurch.
Correct
>In your example, you calculated the current at 48 Volts and it came out
to
>be 320 Amps or 4 times the rated current of my motor at 36 Volts.
>
>If, instead of 48Volts we switched only 12 Volts in, the current would
be 80
>Amps as well.
>
>The question therefore remains:
>
>Assuming I switch from 0 to: 12, 24, 36, and 48 V, is an additional
first
>step with a resistor required for a soft start?
The definitive answer is: It depends! Without knowing the *actual*
resistance of your motor, I'd be guessing. But I'd suspect that the
actual
resistance is lower than I was using for the calculation. But you could
use
12V+resistor as first step (instead of a higher voltage as in the
previous
example), which would significantly reduce the power dissapation of the
resistor.
You stated in another post that you are using a permanent magnet motor.
This is like a shunt motor, but you can't weaken the field to get
smoother
control, so (as Lee indicated) it tries very hard to run at a speed that
is
effectively commanded by the voltage applied.
Unless you can get the contactors cheaply (ie wrecked forklifts etc) I'd
be
getting a controller such as those made by 4QD in the UK (who may have a
controller kit available to reduce your cost and make it a
service-yourself
unit), or a golf cart controller. You could also try your local forklift
service companies, there may be a complete 48V traction control panel
available from a wrecked pallet truck or similar.
Hope this helps
James
--- End Message ---
--- Begin Message ---
At 06:02 AM 25/04/05 -0700, Jeff Shanab wrote:
Thanks for your response James. I plan on getting a zilla 1k for sure but
I can't figure out how to come up with the money right now. I have full
acces to a machine shop so if I can use my time for now, I'll pay myself
with a zilla next year :-)
Can you do "cash" work and save up?
Investing in a zilla up front is $2500, 144V for now is good idea but I
was worried about battery pack age difference. Perhaps that is not too
bad. My philosophy on tires may work <snip>
Could this philosophy work with battery packs. <snip>
Sort of, but badly. If you only lightly use the first year pack it could,
but since it is light-on you are far more likely to deeply discharge it,
reducing its capacity early. It would probably be better to go with flooded
batteries split 72V each end (to maintain weight balance) which would keep
the first year costs down, and allow for cheap "bad-boy" type charging (you
are in the USA? 110/120VAC mains supply?). This would allow for low cost
'rest of system' and a good controller first up. I'd guess at high voltage
you'd be going for Orbitals/etc AGMs eventually?
Just a suggestion, but it may be appropriate to go in the following
upgrading path:
1) Zilla and good contactors, good motor, cheap batteries and cheap charging.
2) Charger upgrade (to an adjustable charger? Madman PFC?), maybe add extra
flooded batteries to increase battery energy stored capacity and transfer
more energy to the motor with no increase to pack amps.
3) Systems to monitor and protect AGMs
4) High-voltage pack of AGMs
5) Woo hoo!! hmm, stronger diff maybe....
On the mechanical PWM controller, <snip> look at these sketches for an
idea of what I am thinking
You have a flaw in your thinking, according to your sketches. Zero PWM,
yes, agree. What you show as 50% PWM is in fact almost 100% - as soon as
any part of both both brushes are on a bar together, you have your path.
The 50% drawing would have only a break of the commutator insulator as off
time. As soon as you have the trailing edge of one brush overlapping the
leading edge of the other, you will be 100% on, but with varying brush
contact areas as the segments go by, putting large currents into the edges
of the brushes. I'll try and illustrate:
[brush 1]
[ ]
[ [brush 2]
[______[_______] <- comm face,
////////||////// drawn flat to be easy
/copper/||////
////////||//
segment
insulator
Hopefully you can see, brush 1 is fully on the segment, brush 2 is
fractionally on the segment, so all the amps are concentrated along the
edge of brush 2. As the comm progresses, the area of brush 2 increases and
reduces on brush 1, to the point where brush 1 is the one with all the amps
along the edge and brush 2 is spread all over. I think that this would
prove to be very hard on the brush edges, it is hard on brushes to be
passing a lot of amps in full-face contact, but this would probably burn
the edges away quite rapidly.
I wouldn't try to build a zilla at home and expect to save money or be
reliable, but maybe I can make a mechaincal PWM at home.
Consider this, probably on the opposite side of your comm assembly, if you
can work out a way to reverse the brush contact areas, with a second set of
brushes in paralell to this set, so when one brush is in fractional
contact, its' mate is in full contact, and vice-versa. Probably need a
cross-connect of comm segments. I haven't thought that through, it is only
a concept thought, but that should get around the small contact patch
problem. Lick that and you may have a winner!
I found a way to make an adjustable current control! It may be made from
off the shelf parts also. The biggest problem with the design right now is
that the user could floor it from a stop and short the pack to the
motor. Probably turn my pack fuse into a flash bulb.
Ideally your "fixed" brush or the throttle to moving brush ratio is altered
by motor RPMs. In the days of steam, double-breasted sandshoes and leather
flywheels that'd be a centrifical actuator on the end of the motor. That
way flooring it when stationary would only bring up 40% or so PWM,
increasing as the motor RPMs built up. How do you think you'd go building
something like that?!
By the time you've built some modern electronics and an actuator to move
the brush system with RPMs, you'd be halfway towards a Zilla.
Be awesome if you can pull it off. Honking great brushes on a big comm for
3000A capacity, with little chance of lock-on failure.
Regards
James
--- End Message ---
--- Begin Message ---
--- Peter VanDerWal <[EMAIL PROTECTED]> wrote:
good morning Peter,
I really want to build/buy a generator to power an
electric trike. (Actually I perfer to buy one but it
seems no one makes one) I am working on a Hughe Pigott
type and agree that it is too heavy/ineffecient but it
is all I can find. I have called eCycle and will talk
to them regarding using their motor/generators for
this application but most of the time when I contact
these comercial producers they are discouraging.
Their products are really not designed to be human
powered. I just do not have the electronic
understanding to design and build one of these on my
own. I do have the mechanical skill to build one. I
have lathes ans mills and welders at my disposal, I
have money set aside for materials, all i need is a
plan that will produce a 90% effecient generator from
human pedaling. I will built it.
> Much better, in my opinion, to use a high efficiency
> motor, like one from
> ecycle.com (96%+), and a single stage chain/belt
> increaser (97-98%
> efficient)
the gear reduction is something like 30:1 not sure
that can be done in one step
. Total would be 94%-95% efficient,
> weight would be approx
> 13lbs (not counting crank arms and pedals).
>
>
They make brushless windmill alternators that are
> even lighter
I have looked for these but cannot seem to find one
that fits the bill please direct me to the appropiate
web site if you know of one
(the ecycle
> motor is more powerfull than necessary) with similar
> efficiency, no idea
> what they cost though.
>
>
> > --- Peter VanDerWal <[EMAIL PROTECTED]> wrote:
> >> Yes it is possible to build a generator that will
> >> work at 70-80 RPM,
> >> unfortunately it would be huge. In order to get
> the
> >> necessary number of
> >> poles and fast enough speed at the coils, it woul
> >> probably need to be
> >> approx 2 feet in diameter
> >
> > actually 2 feet is not that large. if you have a
> bike
> > or exercycle. place the balls of your feet on the
> > pedals now hove another person measure from the
> heel
> > of the shoe farthest from the center to the toe of
> the
> > other and you will find the the circle thus
> defined is
> > something like 27" in diameter therefore a 2 ft
> dia is
> > smaller than what is normally created by anyone
> who
> > pedals a bike. it is just that the normal
> (verticle)
> > orientation of the pedals establishes an elipse
> with a
> > 27 in long axis and a 14 in verticle. If you are
> > building a generator you can use a dia of up to 36
> in
> > and still not interfere pedaling. so just do the
> > electric stuff and i will do the mechanical stuff
> to
> > build one and see what can be generated. i have
> read
> > some about the water and air generators on the
> > internet(hugh piggot etc) but the things they come
> up
> > with are primitive looking and heavy. (based on
> disk
> > brake components) compared to the motors i have
> taken
> > apart where the windings are complex and
> overlapping
> > these brake drum/rotor generators seem not to be
> very
> > sophisticated. I just want to know how many
> magnets
> > and windings (and how to hook up the wires from
> the
> > windings--delta or three phase or ?) i need to
> make
> > generator that wil put out 12-36 volts as many
> amps as
> > possible with my trired old legs???
> >>
> >> It's better (in my opinion) to use a generator
> that
> >> will work with a
> >> single stage speed increaser. Something like a
> 5:1
> >> ratio. Assuming an
> >> 80-90 RPM pedal speed, this works out to about
> >> 400-450 rpm. This is
> >> doable with generators designed for windmills.
> >>
> >>
> >> > peter,
> >> > As you suggest in a personal low speed light
> >> weight ev
> >> > designed for either commuting of touring every
> >> little
> >> > bit helps. With a designed for human power
> >> generator
> >> > even if it is only 75 watts constant that off
> sets
> >> how
> >> > much battery energy you require to accomplish
> your
> >> > goal of distance. The problem is there are no
> >> > specifically designed for human power
> generators.
> >> all
> >> > the ones I have found are not really designed
> to
> >> make
> >> > elecrticity at 60-70 rpm which is what one can
> >> > constantly pedal. instead the generators i
> have
> >> found
> >> > take the slow speed human energy and dilute it
> by
> >> > mechanical means to go faster. in other words
> the
> >> > generators are designed to produce power at
> high
> >> rpms
> >> > and the mechanical/friction losses use up much
> of
> >> the
> >> > human power. Is there no way to make a perm
> mag
> >> > generator that will have the correct number of
> >> poles
> >> > and windings to generate electricity at 60 rpm?
> I
> >> > don't know much about electricity but maybe
> there
> >> is
> >> > someone on the list who does and can explain
> this
> >> to
> >> > me
> >> >
> >> > thanks
> >> > keith
> >> > --- Peter VanDerWal <[EMAIL PROTECTED]> wrote:
> >> >
> >> >> > With a more efficient generator, I am sure
> that
> >> >> you could charge up a
> >> >> > personal electric vehicle of some sort.
> >> Perhaps
> >> >> an electric bicycle.
> >> >
> >> >>
> >> >> With an efficient enough pedal powered
> generator,
> >> >> personal EVs have some
> >> >> advantages. Keeping your workout at a constant
> >> level
> >> >> regardless of terain
> >> >> or traffic for example, or energy banking at
> >> stops.
> >> >
> >> >
> >> >
> >> >
> >> > __________________________________
> >> > Do you Yahoo!?
> >> > Yahoo! Small Business - Try our new resources
> >> site!
> >> > http://smallbusiness.yahoo.com/resources/
> >> >
> >> >
> >>
> >>
> >
> > __________________________________________________
> > Do You Yahoo!?
> > Tired of spam? Yahoo! Mail has the best spam
> protection around
> > http://mail.yahoo.com
> >
> >
>
>
__________________________________________________
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--- End Message ---
--- Begin Message ---
Thanks for the input.
Is there anyway or anywhere I can or get this serviced?
I only noted that the change in voltage cause it is the only thing it
changed before the problem. The charger and battery pack and converter are
all connected the normal way.
I'll get the new fuse different brand same specs on Thursday.
Thanks,
Joe
OhNoJoe wrote:
> I'm having a problem with my Curtis Dc/Dc converter. It used to read
> 14 volts like it was stuck. I did lower the voltage of the charger and
> then the voltmeter showed a much lower reading 12-11.
That implies that the DC/DC is no longer working.
You lowered the voltage of the *charger* and it affected the DC/DC? Why? Is
your charger powering only the DC/DC? A charger isn't designed to do this.
Or, is your charger connected to your main battery pack; and the DC/DC is
also connected to this same main battery pack (the normal way to do it)? In
this case, it shouldn't matter what the charger is, or whether it's turned
on or not, or even connected.
> The input is 110 volts (8x13.75), however, the output is only 11.9
> volts. I thought that maybe the ceramic fuse was blowing. It is a
> Cehess 125 volt or less 8 amp fuse. I pulled it out and tried to find
> a new fuse but can only find glass fuses in town. Can I use the glass
> fuses?
You can check the old fuse with an ohmmeter (your multimeter on the Ohms
scale) to see if it is blown. If it has continuity, it is good.
The original was a ceramic fuse because they are rated to safely break a DC
circuit. The cheaper glass fuses are AC only, and can explode if asked to
break a DC circuit.
--- End Message ---
--- Begin Message ---
Most electric locomotives of the pre-electronic era used, IIRC, series
motors. These can run on AC as well as DC - the magnetic fields reverse,
of course, but since field and armature both change together, the motor
keeps going in the same direction. Even so, the changing field produces
losses; these losses are less at lower frequencies, thus 25 or 16 2/3 Hz
was preferred over 60 or 50.
Steve Gaarder
--- End Message ---
--- Begin Message ---
-----Original Message-----
From: Stu or Jan [mailto:[EMAIL PROTECTED]
Sent: Tuesday, April 26, 2005 8:37 AM
To: '[email protected]'
Subject: RE: Contactor controller, Was:RE: Mechanical PWM Controllers
James,
But you could use
12V+resistor as first step (instead of a higher voltage as in the previous
example), which would significantly reduce the power dissapation of the
resistor.
Do you know how to fabricate a resistor for experimentation?
(Or where to purchase them?)
A 1 ohm resistor at 12 Volts would allow 12 Amps (assuming zero at motor and
wires). I wonder if 144 Watts would get 400 pounds moving?
This may be a solution:
>From Ebay
Designed as a surge or ballast resistor, this unit consists of 3 independent
1 Ohm wirewound resistors wound on a substantial ceramic plate with screw
type connection terminals. We estimate the wattage rating to be about 300
Watts. Probably meant for use with 3 phase motor starting systems to limit
surge current, the resistor has many other uses. Wiring the 3 resistors in
series would give you 3 Ohms or 0.3 Ohms if all wired in parallel. Use as
dummy load for testing batteries, power supplies, amplifiers etc. With
single resistors of this power rating costing around �18.00 each! This could
be the time to pick up a bargain.
BoyntonStu
--- End Message ---
