Re: Modified alternator for use in EV

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Re: Modified alternator for use in EV

Frank John
Hi Mick,

Maybe someone else replied and I missed it - but I believe that as long as the electric motor is still connected physically to the rest of the drivetrain it will spin anything connected to it via chain or coupling.  The motor itself will freewheel i.e. offer no resistance other than minimal bearing resistance, windage, etc. but would still drive an alternator or other accessory.

Can you post details on your alternator conversion?  There's several folks here who regen into their 12 volt accessory battery or run other accessories but regenning into the traction pack has lots of advantages that I can see (and is an idea that I'm exploring as well).

Frank


----- Original Message ----
From: Mick Longley <[hidden email]>
To: [hidden email]
Sent: Tuesday, August 7, 2007 12:15:29 PM
Subject: Re: [EVDL] Modified alternator for use in EV

Can't make something from nothing, that makes total sense. I just thought there might be some use for a cheap and easy way to make 140-200V AC (without rectifier) or DC from an alternator.

I am thinking about the regen possibilities though. Would short bursts of 140Vdc going down hill provide a sufficient charge to make this adaptation worthwhile?

- I would put a micro switch on the pot box that would trigger when the pedal is at no throttle. (this would allow for coasting regen)
- The micro switch would supply +12Vdc from the accessory battery to the field input on the modified alternator.
- Depending on the coast speed, this has the potential of creating 200VDC or AC.

The only question I have is about the behavior of an electric motor when coasting. I have read that clutches are somewhat unnecessary due to electric motors free spinning. How can a free spinning motor turn an alternator that requires some force? Is there a piece I am missing?

Thanks for the input!

Mick
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Re: Modified alternator for use in EV

Roland Wiench
Hello Frank,

My EV has driven a alternator, power steering, A/C, vacuum pump and water
pump for heating many different ways.  Originally, all these devices were
driven by a large motor, as big as a ADC 7 or 8 at a rpm of 1500 to 2000
rpm.

The problem here, I was going up a very steep long hill to work every day,
and when I came down, this vehicle would get up to 80 mph which became too
dangerous at times.  There was no room to install the REGEN braking system.
It was test one time, by hanging a very large resistor off the front bumper
which was 18 inches long and 10 inches square.  It got red hot on that test.

I then direct couple the pilot shaft to a accessory drive system. I use a
GMC diesel accessory mount that is normally mounted on the front of the
engine.  I mounted this unit to a 1/2 thick aluminum plate that is bolted
down to a separate welded in cross members with eight rubber donut type
engine mounts.

There is a brackets and places that the GMC units fit, even a GMC vacuum
pump that works very good with a canister mount.

I found there was little drag on the motor while the A/C was off, and
alternator and power steering was at a lite load. During heavy loads, this
would increase my ampere-hour by about .5 ah.

The existing motor drive that was driving these accessories by mulitiple
belts would pull between 20 and 25 amps off the battery.  So this is a
additional current pulling off the batteries.

Make sure the accessory drive motor feed lines do not come off before the
battery ampere shunt, but after the shunt, otherwise you will get a error in
battery ampere usage.

Now the advantage I had with this main motor direct drive system which use a
Dodge Dyna Flex coupler to a shaft that is mounted with two face bearings
that is mounted on both sides of the GMC accessory plate, is that when I let
up on the accelerator on a very step icy hill, and have the large inverter
alternator loaded up to provide 120 VAC 7 KW power to three heaters, three
fans and lighting, which now holds the EV at speed when going down the hill.

Looking at the battery amp and motor amp gages at this time, they all read 0
amps.

The third method I am using now, is the combination of small electric motors
driving each accessory plus still driving my a series of multiple belts
coming off a electric clutch that is mounted between the motor pilot shaft
and accessory drive unit.  You can get this electric drive from Dodge Power
Transmission Inc which is a Device that is a inline shaft.  Cost about
$1500.00.  I was able to duplicated this electric clutch by modified one of
the large early model A/C pumps which has a longer shaft than the new pumps
have.

Install a grease fitting in this A/C unit and pack it with white wheel
bearing grease.  Its been working great for about 4 months now, since I
install it.

I am using four IOTA DC-DC converters connected in series/parallel to
provide 24 to 28 volts to the separate drive motors on each accessory.  A
good motor I found is a 24 volt DC 1/2 HP that is a totally enclosed motor
from Currie Technologies use on there Ebikes. There source is
[hidden email]  or 1 800 377 4532.

This motor has a internal gear of about 3 to 1 ratio and installing taper
lock pulley to provide another 3 to 1 ratio, you have plenty of power with
this motor.  One motor will get me up to 15 mph with my bike in a very fast
jerk.

I haven't finish wiring up the electric motors yet, except the power
steering is a electric driven anyway.  Now the way this system will work, is
when the main motor is under power, a micro switch on the accelerator
disconnects the electric clutch drive and turns on the DC-DC contactors to
the accessory electric motors.

When the accelerator is let up while coasting, then the electric clutch is
engage and the accessory motors go off the line, and again motor and battery
ampere is reading 0 amps.

Roland


----- Original Message -----
From: "Frank John" <[hidden email]>
To: "Electric Vehicle Discussion List" <[hidden email]>
Sent: Wednesday, August 08, 2007 6:52 AM
Subject: Re: [EVDL] Modified alternator for use in EV


> Hi Mick,
>
> Maybe someone else replied and I missed it - but I believe that as long as
> the electric motor is still connected physically to the rest of the
> drivetrain it will spin anything connected to it via chain or coupling.
> The motor itself will freewheel i.e. offer no resistance other than
> minimal bearing resistance, windage, etc. but would still drive an
> alternator or other accessory.
>
> Can you post details on your alternator conversion?  There's several folks
> here who regen into their 12 volt accessory battery or run other
> accessories but regenning into the traction pack has lots of advantages
> that I can see (and is an idea that I'm exploring as well).
>
> Frank
 

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Re: Modified alternator for use in EV

Mick Longley
In reply to this post by Frank John
Hi Frank,
Thanks for the info, follow this link to find out how to modify an alternator to put out more than 13-14Vdc or AC if you prefer.

http://mywebpages.comcast.net/t.molnar/

What would be more efficient to charge the traction pack - AC into the charger or DC directly into the pack?

Mick


----- Original Message ----
Date: Wed, 8 Aug 2007 05:52:00 -0700 (PDT)
From: Frank John <[hidden email]>
Subject: Re: [EVDL] Modified alternator for use in EV
To: Electric Vehicle Discussion List <[hidden email]>
Message-ID: <[hidden email]>
Content-Type: text/plain; charset=us-ascii

Hi Mick,

Maybe someone else replied and I missed it - but I believe that as long
 as the electric motor is still connected physically to the rest of the
 drivetrain it will spin anything connected to it via chain or
 coupling.  The motor itself will freewheel i.e. offer no resistance other than
 minimal bearing resistance, windage, etc. but would still drive an
 alternator or other accessory.

Can you post details on your alternator conversion?  There's several
 folks here who regen into their 12 volt accessory battery or run other
 accessories but regenning into the traction pack has lots of advantages
 that I can see (and is an idea that I'm exploring as well).

Frank

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Re: Modified alternator for use in EV

Lee Hart
Mick Longley wrote:
> What would be more efficient to charge the traction pack - AC into
> the charger or DC directly into the pack?

All generators are AC at heart; the windings always generate AC. You
basically have two ways to rectify it; solid-state diodes or a
commutator and brushes. Done right, both work very well. Done badly or
on the cheap, both can lead to poor results.

Normal car generators and alternators are examples of doing it cheaply.
They have rather low efficiency; on the order of 60-70%. But there are
some large, more efficient units intended for commercial trucks and
buses. If you want serious amounts of power for anything more than a few
minutes at a time, these are the ones to use.

Getting outside of automotive grade parts can significantly raise your
efficiency. A normal DC shunt motor (a.k.a. generator) is 75-85%
efficient. You'll need one wound for a voltage at least close to your
intended pack voltage. For instance, a 48v nameplate motor might make it
to 100v, but not likely much more without rewinding.

You can replace the field of a series DC motor with a shunt field, to
make it much easier to control as a generator. The brush timing also
needs to be changed for generator operation.

PM DC generators can top 90% efficiency. However, the voltage they
generate is strictly set by RPM. If you can vary the driving engine's
speed (like a generator trailer for an EV), then these are the most
efficient. But if it is for regenerative braking where RPM has to vary,
then you need a separate controller to change the generated voltage to
match your pack voltage.

AC motors can also be used as generators (ANY motor can be used as a
generator!) Induction motors require a set of capacitors, so it always
sees a capacitive load. Then you add a set of rectifiers, exactly like
you find in auto alternators. Induction generators behave like PM
generators, in that the voltage you get is strictly set by RPM.

There are some PM AC motors (called synchronous motors or brushless DC
motors) that can be used as generators. They also have high efficiency,
but are generally very expensive.

Hope this helps!
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in    --    Leonard Cohen
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Re: Modified alternator for use in EV

Jeff Shanab
In reply to this post by Frank John
How about a 10Kwh permanent magnet 3phase generator for about 500$ ?

ebay : 330135056935


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Re: Modified alternator for use in EV

Zeke Yewdall
10kWh isn't going to get you very far.... 20 or 30 miles at most.
10kW might be useful though.

On 8/10/07, Jeff Shanab <[hidden email]> wrote:
> How about a 10Kwh permanent magnet 3phase generator for about 500$ ?
>
> ebay : 330135056935
>
>
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Re: Modified alternator for use in EV

gowen
In reply to this post by Jeff Shanab
Jeff Shanab wrote:
> How about a 10Kwh permanent magnet 3phase generator for about 500$ ?
>
> ebay : 330135056935

Is anyone using the Honda IMA motors?  The newer ones run more towards
20Kw if I read things correctly.  Any idea if they can be controlled
without proprietary information?

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Re: Modified alternator for use in EV

TrotFox Greyfoot
The Honda motors are PM rotor brushless DC motors.  They shouldn't
need controllers to act as gensets.  Granted, you're going to get AC
out but that shouldn't be too much of a concern since everyone is
looking for that anyway...

Trot, the post-Insight, fox...

On 8/10/07, Greg Owen <[hidden email]> wrote:
>
> Is anyone using the Honda IMA motors?  The newer ones run more towards
> 20Kw if I read things correctly.  Any idea if they can be controlled
> without proprietary information?

--
|  /\_/\       TrotFox         \ Always remember,
| ( o o ) AKA Landon Solomon \ "There is a
|  >\_/<       [hidden email]       \ third alternative."

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Re: Modified alternator for use in EV

gowen
TrotFox Greyfoot wrote:
> The Honda motors are PM rotor brushless DC motors.  They shouldn't
> need controllers to act as gensets.  Granted, you're going to get AC
> out but that shouldn't be too much of a concern since everyone is
> looking for that anyway...

I was thinking as a motor, actually, with regenerative braking
capabilities, instead of just using it as a genset.

Some good pages here:

http://www.insightcentral.net/encyclopedia/enmotor.html
http://www.insightcentral.net/encyclopedia/enmdm.html
http://www.insightcentral.net/encyclopedia/enmcm.html

In short, the MDM takes DC from the battery and turns it into pseudo-AC
to run the motor.  When the motor is instead generating, the MDM takes
that real AC and turns it back into DC.

The MDM and MCM are the big questions in my mind.  They seem to be the
brains that make the system work.  So if you had these three components,
could you hook them up and use them?  Do they take standard CAN protocol
and are their command sets known?

Inquiring minds want to know.

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Re: Modified alternator for use in EV

Jeff Shanab
In reply to this post by Frank John
I can't believe I did that. "error detected between user and keyboard"

I tried to determine how much if at all the civic hybrids one may be. I
think 15kw and weather this is an absolute max or if we can push it by
running a higher rpm for example. Perhaps combining it with a modified
outboard motor in a gen trailer as they have strict emmision standards
on them.

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Re: Modified alternator for use in EV

Jeff Shanab
In reply to this post by Frank John
I was talking about using it as an alternator. Not controller needed!

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Re: Modified alternator for use in EV

gowen
In reply to this post by Jeff Shanab
Jeff Shanab wrote:
> I tried to determine how much if at all the civic hybrids one may be.
> I think 15kw and weather this is an absolute max or if we can push it
> by running a higher rpm for example. Perhaps combining it with a
> modified outboard motor in a gen trailer as they have strict emmision
> standards on them.

It seems to vary, and I don't see specifications clearly stated anywhere
online.   Any Honda mechanics on-list?

Insight Central says that the Insight has a 10 kW permanent magnet DC
brushless motor: http://www.insightcentral.net/encyclopedia/enspecs.html.

Wikipedia says the 1st generation Civic hybrid has a 15 kW (20 hp)
brushless, permanent magnet assist motor.  It notes that the 2nd gen
Civic has 4th generation IMA, but doesn't give specs.
http://en.wikipedia.org/wiki/Honda_Civic_Hybrid.

Honda's site seems to agree, saying the 2007 Civic has a "20 hp / 76
lb.-ft." motor at
http://automobiles.honda.com/civic-hybrid/specifications.aspx?group=all.

The permanent magnets are on the rotor and the windings are on the
stator, which, as I understand it, would make it more tolerant of higher
RPM.  Please, correct me if I'm wrong.

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