# [EVDL] Re generative Braking



## EVDL List (Jul 27, 2007)

The best solution that I have heard of or seen for an application like
you have (very similar to my application also) is to rewind an
automotive alternator for you packs charging voltage and attach it to
your motors tailshaft. This is something I'd like to do eventually for
my car. I will then use the brake switch to activate it. I would like
to also add a controller to it that will allow me to control the
amount of regen current/braking.

If you have more money, you might find a permanent magnet
motor/generator designed for the job. Remember that DC generators are
also motors and need to be electrically disconnected when not
generating. AC generators/alternators need a diode bridge to get DC
out of them.

-Jon Glauser
http://jonglauser.blogspot.com
http://www.evalbum.com/555

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## EVDL List (Jul 27, 2007)

> On 10 Nov 2008 at 9:43, Jon Glauser wrote:
> 
> > ... rewind an automotive alternator for your pack's charging voltage
> > and attach it to your motor's tailshaft.
> ...


----------



## EVDL List (Jul 27, 2007)

Doug and All,
My RX-7 came with this Solar Car Corporation alternator system from a previous converter:
http://www.evalbum.com/tech/regen.jpg

I found the above link in the archives at:
http://www.mail-archive.com/[email protected]/msg07960.html

I'm thinking that Roderick Wilde at EV Parts built one of these for their
Land Rover, but I don't think they made them available.
Suck Amps,
BB

>Date: Mon, 10 Nov 2008 07:59:01 -0800 (PST)
>From: dwinmac
>
>I have a 1987 Ford Ranger that I converted to electric power using the kit
>from EV-America.com. The 120 VDC system uses 20 T-145 Trojan 6 volt
>batteries, a Curtis 1231C-8601 controller and a series wound Advanced DC
>Motor FB1-4001A motor. The system design does not include regenerative
>braking. 
>
>See pictures at http://web.mac.com/doug1939/Site/Electric_Vehicle.html
>
>Searching the internet and this forum for information on regenerative
>braking it seems that safe regenerative braking with a series wound DC
>motor is problematic. Safety is a big issue as far as I am concerned.
>
>Another approach I saw suggested was to insert a separate generator in the
>drive train to act strictly as regenerative braking. From a Systems
>Engineering point of view I could use some help defining such a design.
>
>Minimizing size and weight are important.
>AC or DC generator?
>Output voltage to batteries 120 VDC (or higher?)
>Current output at least 25 amps 
>What is the maximum input amps to the batteries without affecting battery
>life?
>Is there a controller on the market to handle just the generator in such a
>system?
>Safety issues using such a system?
>Ultimate question - where to hook the generator into the drivetrain.
>
>I would also appreciated any information on books or other documents
>already available that would be helpful. Thanks!



>Date: Mon, 10 Nov 2008 09:43:32 -0700
>From: "Jon Glauser"
>
>The best solution that I have heard of or seen for an application like
>you have (very similar to my application also) is to rewind an
>automotive alternator for you packs charging voltage and attach it to
>your motors tailshaft. This is something I'd like to do eventually for
>my car. I will then use the brake switch to activate it. I would like
>to also add a controller to it that will allow me to control the
>amount of regen current/braking.
>
>If you have more money, you might find a permanent magnet
>motor/generator designed for the job. Remember that DC generators are
>also motors and need to be electrically disconnected when not
>generating. AC generators/alternators need a diode bridge to get DC
>out of them.
>
>-Jon Glauser
>http://jonglauser.blogspot.com
>http://www.evalbum.com/555

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## EVDL List (Jul 27, 2007)

A Google search for Solar Car Corporation revealed the company is out of
business. That is a shame because that part looks really interesting and
would be perfect for my conversion. Any idea if any other manufacturers
exist that bought this product from Solar Car Corporation? Maybe GM has it
now.


Sincerely,
Douglas A. Stansfield

[email protected]
Fax: 973-440-1619
Cell: 973-670-9208

Licenses NJ (1046359), NY (LB-1010062)

Securities offered through:
Fortune Financial Services, Inc.
1010 Third Avenue
New Brighton, PA 15066 
724-846-2488
Member FINRA
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of Dave (Battery Boy) Hawkins
Sent: Monday, November 10, 2008 5:35 PM
To: [email protected]
Subject: Re: [EVDL] Re generative Braking

Doug and All,
My RX-7 came with this Solar Car Corporation alternator system from a
previous converter:
http://www.evalbum.com/tech/regen.jpg

I found the above link in the archives at:
http://www.mail-archive.com/[email protected]/msg07960.html

I'm thinking that Roderick Wilde at EV Parts built one of these for their
Land Rover, but I don't think they made them available.
Suck Amps,
BB

>Date: Mon, 10 Nov 2008 07:59:01 -0800 (PST)
>From: dwinmac
>
>I have a 1987 Ford Ranger that I converted to electric power using the kit
>from EV-America.com. The 120 VDC system uses 20 T-145 Trojan 6 volt
>batteries, a Curtis 1231C-8601 controller and a series wound Advanced DC
>Motor FB1-4001A motor. The system design does not include regenerative
>braking. 
>
>See pictures at http://web.mac.com/doug1939/Site/Electric_Vehicle.html
>
>Searching the internet and this forum for information on regenerative
>braking it seems that safe regenerative braking with a series wound DC
>motor is problematic. Safety is a big issue as far as I am concerned.
>
>Another approach I saw suggested was to insert a separate generator in the
>drive train to act strictly as regenerative braking. From a Systems
>Engineering point of view I could use some help defining such a design.
>
>Minimizing size and weight are important.
>AC or DC generator?
>Output voltage to batteries 120 VDC (or higher?)
>Current output at least 25 amps 
>What is the maximum input amps to the batteries without affecting battery
>life?
>Is there a controller on the market to handle just the generator in such a
>system?
>Safety issues using such a system?
>Ultimate question - where to hook the generator into the drivetrain.
>
>I would also appreciated any information on books or other documents
>already available that would be helpful. Thanks!



>Date: Mon, 10 Nov 2008 09:43:32 -0700
>From: "Jon Glauser"
>
>The best solution that I have heard of or seen for an application like
>you have (very similar to my application also) is to rewind an
>automotive alternator for you packs charging voltage and attach it to
>your motors tailshaft. This is something I'd like to do eventually for
>my car. I will then use the brake switch to activate it. I would like
>to also add a controller to it that will allow me to control the
>amount of regen current/braking.
>
>If you have more money, you might find a permanent magnet
>motor/generator designed for the job. Remember that DC generators are
>also motors and need to be electrically disconnected when not
>generating. AC generators/alternators need a diode bridge to get DC
>out of them.
>
>-Jon Glauser
>http://jonglauser.blogspot.com
>http://www.evalbum.com/555

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Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev

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----------



## EVDL List (Jul 27, 2007)

this might be inspiring:
http://www.northrim.net/wyanders/ev/regeneration.html

-Jon Glauser
http://jonglauser.blogspot.com
http://www.evalbum.com/555

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## EVDL List (Jul 27, 2007)

What precisely is the problem with regen on a DC motor?
Is it that such a controller is more complex?
Does it just require a good Electrical Engineer to
focus on it?

I have a Zilla on my workbench and a tentative
appointment with a friend who is an engineer.
He couldn't afford to spend thousands on a CNC
machine, so he got a $700 machineshop and built
the CNC part himself. He rewinds motors often.

If I could show him a market, maybe he would spend
some time on it.

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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Re generative braking*

> While AC is the most simple way to get regen, another, I don't see 
> mentioned is a sepex motor. That's a DC motor with seperately 
> excited fields. These are used to regen often, but aren't as 
> available as a basic series wound motor.

There was mention of shunt-wound, which includes sepex - this 
specifically refers to using a controller that has a second low 
voltage controllers in the same unit to handle the field control.

By the way, I have a copy of Dr. Jackson's "Regenerative Braking with 
DC Series Motors", printed in 1997, developed with Advance DC motors 
and Curtis controllers in mind. If I used this I would have a high 
current/low voltage DCC instead of a separate 6V floodie for the 
field -- don't know what this would do to the brushes unless you also 
added adjustable brush timing.


Think more
Talk less
Become wise

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## EVDL List (Jul 27, 2007)

> I am confoozed. I thought a sepex motor was just a series wound DC
> motor where A1 and A2 went to one chopper, and F1 and F2 went to a
> different chopper and not to A1/A2 in any way. Does the motor need to
> be wound differently? What would the differences be?

Two things: a SepEx motor often has the field wound for higher voltage
and lower current. More importantly, a SepEx motor has separate
windings called interpoles that balance out the field and prevent
arcing.

> Even with a series motor, re-gen is not impossible but it will
> require one of two architctures to avoid the typical issues
> with the series motor characteristics:

The motor gurus on the list have suggested that the first solution
causes increased stress on the motor if it doesn't have interpoles.

Your second solution sounds interesting to me. This is essentially
what Otmar did in his regen experiments. Use contactors (and diodes)
to reverse the motor direction, and use the motor controller as a
boost converter.

However, a series motor under regen is a tricky beast. It's non-linear
(due to saturation and the field strength changing with current). In
addition, it has negative stability in its voltage-current
characteristic: an increasing current will cause it to generate more
voltage, making it act like a non-linear negative resistor.

All sorts of bad things can happen in thought experiments with
negative resistors. For example, imagine if, in regen, the current
rose enough that the back EMF exceeded the pack voltage. Even with the
MOSFETs off, the diodes would conduct and you would have voltage
across the inductor. This would cause increasing current and
increasing voltage. If there was enough resistance in the
motor-diode-wiring-battery loop, you would find a stable steady-state
where the motor would be stuck at a steady level of regen until the
RPMs decreased enough. If the resistances were too low, the system
would go out of control, increasing the voltage and current until
something fries.

I haven't done any analysis of this situation; maybe I made a mistake
and this can't happen. Maybe it only loses control if the resistance
is too low.

With neutrally timed brushes and a good control algorithm, I think it
might work OK. I think this would be very interesting to experiment
with. I don't have time for such a project in the foreseeable future,
though.

Read Otmar's regen article here:

http://cafeelectric.com/curtis/regen/index.html

-Morgan LaMoore



> Cor van de Water <[email protected]> wrote:
> > They are quite common on small EVs like some golf carts
> > and on Reva, wich can easily send 140A back into the batteries
> > per my own measurement from its sepex DC motor.
> ...


----------



## EVDL List (Jul 27, 2007)

> dwinmac <[email protected]> wrote:
> >
> 
> > Minimizing size and weight are important.
> ...


----------



## EVDL List (Jul 27, 2007)

Doug mentioned it -- effectively the same as a shunt motor, thought the
exact winding resistance may be different. Like he said.... very hard to
find, and even harder to find a controller for a full sized EV
application.... I have a motor, but no controller yet 

Z

On Mon, Nov 10, 2008 at 11:44 PM, Jon Bishop
<[email protected]>wrote:

>
>


> Doug MacDonald wrote:
> > > << If you want regen, or think you might in your wildest dreams, I
> > > think you
> > > << really try to should start your conversion with a motor that's
> ...


----------



## EVDL List (Jul 27, 2007)

I found all sorts of motors in all HP ratings at this site

http://www.tdigrp.com/products/381/

Course they are mostly 230 and 250 VDC motors.
Took me 2 minutes. What I find totally amazing is they dont rate by diam=
eter.

Dan Bentler


C-2E - (1) Set - 4 MD 808 Shunt Field CoilsC-2E - (1) Set - 4 MD-806 Pole P=
iecesC-E-5052 - 10 HP, MD 802CAE, 230 VDC, Shunt, 900 RPM, Mill MotorTDI E-=
1574 - 10/20 HP, PMD803AA, 230 Volt DC, 800/1600 RPM, Mill MotorTDI E-1225 =
- 100 HP, 515 RPM, 230 VDC GE Mill MotorTDI E-1167 - 100 HP, 515 RPM, 230 V=
DC Mill MotorC-E-3039 - 100 HP, 515 RPM, 230V DC Mill MotorTDI E-0577 - 100=
HP, PMD 814, 230 VDC, 500 RPM Mill MotorTDI E-1833 - 100/135 HP, MD 812AE,=
230 Volt DC, Series, 475/420 RPM, Mill MotorE-0069 - 14 HP, MD 806, 230 VD=
C, Shunt, 325/975 RPM, Mill MotorE-0062 - 14 HP, MD 806, 230 VDC, Shunt, 32=
5/975 RPM, Mill MotorTDI E-1379 - 15 HP, MD 803AE, 230 VDC, 900 RPM, Mill M=
otor FRAME ONLYTDI E-0459 - 15 HP, MD 803AE, 230 VDC, Compound, 800 RPM, Mi=
ll MotorTDI E-1357 - 15 HP, MD 803AE, 230 VDC, Shunt, 500 RPM, Mill MotorTD=
I E-1160 - 150 HP, 500 RPM, 230 VDC Mill MotorTDI E-1224 - 150 HP, MD 814AE=
, 230 VDC, Compound, 500 RPM, Mill MotorTDI E-1164 - 150 HP, MD
814AE, 230 VDC, Compound, 500 RPM, Mill Motor111284 - 150/200 HP, MD 814, =
230 VDC, Series, 460/400 RPM Mill Motor110627 - 20 HP, MD 808AE, 230 VDC, S=
hunt FRAME ONLYTDI E-1045 - 20/26 HP, 650/580 RPM, 230V DC Mill MotorTDI E-=
0966 - 20/26 HP, 650/580 RPM, 230V DC Mill Motor110449 - 20/26 HP, MD 804AE=
, 230 VDC, Series FRAME ONLYTDI E-1442 - 20/26 HP, MD 804AE, 230 VDC, Serie=
s, 650/580 RPM, Mill Motor FRAME ONLYTDI E-1694 - 20/26 HP, MD 804AE, 230 V=
olt DC, Series, 650/580 RPM, Motor109210 - 200/265 HP, MD 816AE, 230 Volt D=
C, Series, 450/400 RPM, Mill MotorC-E-3710 - 250 HP, MD 818AEL, 230 VDC, Sh=
unt, 435 RPM, Mill MotorC-E-3707 - 250 HP, MD 818AEL, 230 VDC, Shunt, 435 R=
PM, Mill MotorTDI E-1526 - 250 HP, MDP 818AEL, 230/460 VDC, Shunt, 435 RPM,=
Mill MotorTDI E-1567 - 250/500 HP, MD 818AEL, 230/460 VDC, 435/870 RPM, Mi=
ll MotorTDI E-1566 - 250/500 HP, MD 818AEL, 230/460 VDC. Shunt, 435/870 RPM=
, Mill Motor110631 - 30 HP, MD 806, 230 VDC, Compound FRAME ONLYTDI
E-0072 - 30 HP, MD 806, 230 VDC, Stab Shunt, 650/1950 RPM, Mill MotorTDI E=
-2062 - 30 HP, MD 806AE, 230 Volt DC, Shunt, 650 RPM, Mill Motor110628 - 30=
/39 HP, MD 806 230 VDC, Series FRAME ONLY108817-001-00 - 30/39 HP, MD 806AE=
, 230 VDC, Series, 525/450 RPM, Mill Motor FRAME ONLY108819 - 30/39 HP, MD =
806AE, 230 VDC, Series, 575/500 RPM, Mill MotorTDI E-1584 - 30/39 HP, MD 80=
6AE, 230VDC, Series, 575/500RPM, Mill Motor FRAME ONLYTDI E-1485 - 300 HP, =
MDP 818AER, 230 VDC, Shunt, 435 RPM, Mill MotorTDI E-0403 - 50 HP, 575/1725=
RPM, 230V DC Mill MotorTDI E-0402 - 50 HP, 575/1725 RPM, 230V DC Mill Moto=
rTDI E-0263 - 50 HP, MD 808, 230 VDC, Stab Shunt, Mill MotorTDI E-1618 - 50=
HP, MD 808AA, 230 Volt DC, Shunt, Mill Motor FRAME ONLYTDI E-1619 - 50 HP,=
MD 808AA, 230 Volt DC, Shunt, Mill Motor FRAME ONLYTDI E-1359 - 50 HP, MD =
808AE, 230 VDC, Shunt, 575 RPM, Mill MotorTDI E-1690 - 50 HP, MD 812AER, 23=
0 Volt DC, Shunt, 575 RPM, MotorTDI E-0965 - 50 HP, MD 818 AEL, 230
VDC, Shunt, 80 RPM, Mill MotorC-E-5068 - 50 HP, MDP 808AE, 230 VDC, Series=
, 525 RPM, Mill MotorC-E-3720 - 50 HP, MDT 818AEL, 230 VDC, Shunt, 80 RPM, =
Mill MotorC-E-3718 - 50 HP, MDT 818AEL, 230 VDC, Shunt, 80 RPM, Mill MotorT=
DI E-1644 - 50 HP, MDV 808AER, 230 Volt DC, Shunt, 575 RPM, Mill Motor ARMA=
TURE ONLYTDI E-0907 - 50/60 HP, MD 808 AE, 250 VDC, Series, 525/450 RPM, Mi=
ll MotorTDI E-0707 - 50/65 HP, 525/450 RPM, 230V DC Mill MotorTDI E-1048 - =
50/65 HP, 525/450 RPM, 230V DC Mill Motor110620 - 50/65 HP, MD 808 ARMATURE=
ONLY110624 - 50/65 HP, MD 808 ARMATURE ONLYTDI E-1285 - 50/65 HP, MD 808AE=
, 230 VDC, Series, 525/450 RPM, Mill MotorTDI E-1049 - 50/65 HP, MD 808AE, =
230 VDC, Series, 525/450 RPM, Mill MotorTDI E-0967 - 50/65 HP, MD 808AE, 23=
0 VDC, Series, 525/450 RPM, Mill MotorTDI E-1043 - 50/65 HP, MD 808AE, 230 =
VDC, Series, 525/450 RPM, Mill MotorTDI E-1325 - 50/65 HP, MD 808AE, 230 VD=
C, Series, 525/450 RPM, Mill Motor

----- Original Message ----
From: Zeke Yewdall <[email protected]>
To: Electric Vehicle Discussion List <[email protected]>
Sent: Tuesday, November 11, 2008 6:24:41 AM
Subject: Re: [EVDL] Re generative Braking

Doug mentioned it -- effectively the same as a shunt motor, thought the
exact winding resistance may be different. Like he said.... very hard to
find, and even harder to find a controller for a full sized EV
application.... I have a motor, but no controller yet 

Z

On Mon, Nov 10, 2008 at 11:44 PM, Jon Bishop
<[email protected]>wrote:

>
>


> Doug MacDonald wrote:
> > > << If you want regen, or think you might in your wildest dreams, I
> > > think you
> > > << really try to should start your conversion with a motor that's
> ...


----------



## EVDL List (Jul 27, 2007)

Otmar mentions longer brake life as one of the side benefits
of regen braking.
I just saw a report of a Prius owner who has over 200,000
miles on his 2001 Prius with still the original brakes....
Also I saw no visible wear after 50k miles on mine,
just another datapoint for people considering regen braking...

Regards,

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 VoIP: +31 20 3987567 FWD# 25925
Tel: +91 (040) 23117400x109 XoIP: +31877841130

-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Morgan LaMoore
Sent: Thursday, November 13, 2008 3:09 AM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Re generative Braking

> I am confoozed. I thought a sepex motor was just a series wound DC 
> motor where A1 and A2 went to one chopper, and F1 and F2 went to a 
> different chopper and not to A1/A2 in any way. Does the motor need to

> be wound differently? What would the differences be?

Two things: a SepEx motor often has the field wound for higher voltage
and lower current. More importantly, a SepEx motor has separate windings
called interpoles that balance out the field and prevent arcing.

> Even with a series motor, re-gen is not impossible but it will require

> one of two architctures to avoid the typical issues with the series 
> motor characteristics:

The motor gurus on the list have suggested that the first solution
causes increased stress on the motor if it doesn't have interpoles.

Your second solution sounds interesting to me. This is essentially what
Otmar did in his regen experiments. Use contactors (and diodes) to
reverse the motor direction, and use the motor controller as a boost
converter.

However, a series motor under regen is a tricky beast. It's non-linear
(due to saturation and the field strength changing with current). In
addition, it has negative stability in its voltage-current
characteristic: an increasing current will cause it to generate more
voltage, making it act like a non-linear negative resistor.

All sorts of bad things can happen in thought experiments with negative
resistors. For example, imagine if, in regen, the current rose enough
that the back EMF exceeded the pack voltage. Even with the MOSFETs off,
the diodes would conduct and you would have voltage across the inductor.
This would cause increasing current and increasing voltage. If there was
enough resistance in the motor-diode-wiring-battery loop, you would find
a stable steady-state where the motor would be stuck at a steady level
of regen until the RPMs decreased enough. If the resistances were too
low, the system would go out of control, increasing the voltage and
current until something fries.

I haven't done any analysis of this situation; maybe I made a mistake
and this can't happen. Maybe it only loses control if the resistance is
too low.

With neutrally timed brushes and a good control algorithm, I think it
might work OK. I think this would be very interesting to experiment
with. I don't have time for such a project in the foreseeable future,
though.

Read Otmar's regen article here:

http://cafeelectric.com/curtis/regen/index.html

-Morgan LaMoore

On Tue, Nov 11, 2008 at 4:12 AM, Cor van de Water <[email protected]>


> wrote:
> > They are quite common on small EVs like some golf carts and on Reva,
> > wich can easily send 140A back into the batteries per my own
> > measurement from its sepex DC motor.
> ...


----------



## EVDL List (Jul 27, 2007)

They don't give torque/rpm curves, or the size and weight (which would
determine how much thermal mass it has for short operation at higher than
continuous power). Which is understandable, since they are selling them for
continuous fixed speed operation, rather than variable speed, highly
temporarily overloaded operation, like an EV sees...

I wonder what a 20HP/600rpm shunt motor weighs..... I guess the low rpm
could fit a direct drive system well, depending on what the max safe rpm
is...

Z



> Cor van de Water <[email protected]> wrote:
> 
> > Otmar mentions longer brake life as one of the side benefits
> > of regen braking.
> ...


----------

