Robert MacDowell | 1 Jul 2008 01:03
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Towing DC motors

What happens if a DC traction motor is spun free, without either 
powering it or attaching a regenerative load to it?   Can the back EMF 
generated actually damage the motor?  Now, what if the brushes are 
removed from the brush holders (to isolate the armature)?

The problem vehicle is a streetcar overhead wire maintenance car,
http://world.nycsubway.org/perl/show?16119
with 4 motors in series/parallel  <at>  600 volts DC. One motor is bad and 
awaiting repair, so we removed brushes from that motor and its mate to 
isolate them (giving us an underpowered 2-motor car).  Concern is over 
damaging the good motor in the pair.  Any thoughts?

Robert

Richard Acuti | 1 Jul 2008 01:11
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Re: The AMPhibian is alive.


John,

That thing is too cool. I'm really jealous, it looks like a lot of fun and I can only imagine the uses it could have.
__________________________________
Message: 1
Date: Mon, 30 Jun 2008 10:47:04 -0700 (PDT)
From: AMPhibian 
Subject: [EVDL] The AMPhibian is alive.
To: ev@...
Message-ID: 
Content-Type: text/plain; charset=us-ascii

Got it operational yesterday afternoon and I love it!
Some videos of it in action:
http://www.youtube.com/user/JRP3
Check out my blog and evalbum.com/1609 for details.
Thanks to everyone here for all the help.
John
________________________________

Rich A.
Maryland
http://www.austinev.org/evalbum/371.html
http://patriotfuel.blogspot.com/

_________________________________________________________________
The other season of giving begins 6/24/08. Check out the i’m Talkathon.
http://www.imtalkathon.com?source=TXT_EML_WLH_SeasonOfGiving

(Continue reading)

damon henry | 1 Jul 2008 01:12
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Re: Towing DC motors

As long as it is not over revved everything will be fine.  Since there are still good motors in the system
presumably spinning at the same rate, over revving does not appear to be a realistic scenario.

damon

> Date: Mon, 30 Jun 2008 16:03:24 -0700> From: bobmac@...> To:
ev <at> lists.sjsu.edu> Subject: [EVDL] Towing DC motors> > What happens if a DC traction motor is spun free,
without either > powering it or attaching a regenerative load to it? Can the back EMF > generated actually
damage the motor? Now, what if the brushes are > removed from the brush holders (to isolate the armature)?>
> The problem vehicle is a streetcar overhead wire maintenance car,>
http://world.nycsubway.org/perl/show?16119> with 4 motors in series/parallel  <at>  600 volts DC. One
motor is bad and > awaiting repair, so we removed brushes from that motor and its mate to > isolate them
(giving us an underpowered 2-motor car). Concern is over > damaging the good motor in the pair. Any
thoughts?> > Robert> > _______________________________________________> For subscription
options, see> http://lists.sjsu.edu/mailman/listinfo/ev
_________________________________________________________________
The other season of giving begins 6/24/08. Check out the i’m Talkathon.
http://www.imtalkathon.com?source=TXT_EML_WLH_SeasonOfGiving
atc | 1 Jul 2008 01:22
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Re: Motor direction & carbon brushes question


Hey Paul

A motor with an slanted brush has no ill effect in it running either way.
Hope this helps
Jim Husted
Hi-Torque Electric

---

If that is the case is it true for PM motors such as the Etek? I've heard
differing opinions on this with regards to the Etek. The brushes are
"slanted" and one edge is fatter than the other, thus, if the motor is
turning one direction as opposed to the other the leading edge of the brush
is either fatter or narrower.

Bob
--

-- 
View this message in context: http://www.nabble.com/Motor-direction---carbon-brushes-question-tp18186531p18206305.html
Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com.

Bob Rice | 1 Jul 2008 01:22

Re: Rabbit rear wheel alignment

  Hi Chuck an' EVerybiody;

  Gees! Any Rabbbits left?! Hah, they have ALL gone to the Great Junkyard in 
the sky, around here. EVen PARTS are non existant!Well, I probably would 
STILL have mine hsad I not killed it towing it home from Joliet?

  Anyhow I DID have the rear end alignment issue, went through the same shit 
yur going through! I changed the whole damn swing axle rear end, this helped 
to retrurn it so the tires lasted. But with 1200 lbs of batteries It DIOD 
look like it was out of whack in the rear end, but most of that was an 
optical disalusion!Car tracked OK, Even getting my recortd 100 mile run, 
with 20 T145's stuffed aboard!Used to easily do more than 100 miles a day, 
stuffing back power at 70 amps , like at lunch time,on my famous "Lirttle 
Blue Box" charger, half wave setup off the 240 volt mains using BOTH 120 
volt sides. Gave true meaning to "stench Chord"Usually turning those plastic 
range chords into hot silly putty!

   As for rw alignment you get the luck of the draw I guess, I had piles of 
Rabbits I had parted out over the years. Just go out back and dig up a new 
rear swing axle. They change out easy enough, 4 bolts to the chassis, the 
handbrake cables and Hydralic lines. Pain in the ass, as they, brake lines, 
Break,(English? Aint it fun??) and you end up going through the whole damn 
car, but it IS a nice feeling to know ya got new brake lines! But worth it 
when the shop guy can set stuff. I know thery have shimsd to slip under the 
axle bolts, that hold that silly little axle stub on to the axle. The other 
laugh is STOCK Wabbit brake drums. Look like off a motor scooter!Jetta ones 
will bolt on, giving you almost believeable rear brakes?I ran Jettas' for 
years!I guess the VW engineers wern't figguring on 1300 lbs of batteries 
when they designed BARELY enough brakes for the car that they DID 
build.??Well, that goes for the suspension, too. I had BMW springs in back 
(Continue reading)

damon henry | 1 Jul 2008 01:25
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Re: The AMPhibian is alive.

If you need cooling Ryan at EVSource has just the right thing for you.
http://www.evsource.com/tls_blowers.php
I would make sure you need to add it first.  As you said, you need some instrumentation.  You can start with your
hand.  What does the motor feel like after you go for a spin?  If it just feels warm or slightly hot you are
probably just fine.  Do you have a temperature probe?  Even a meat thermometer can give you some indication. 
Slip it in the brush cover and read the temp on the brushes a couple of minutes (waiting a few minutes allows
the heat to migrate out from the core of the motor) after going for a ride.  I have the blower on my motor setup
to turn on with an 80C switch mounted on the brushes.  Anything below that I do not worry about.  The
insulation in the motor is rated at 180C.

If you do need to add cooling a fan is not what you need.  You need a blower to force air through the motor from the
brush side.  This also means that you will need a new brush cover with a port for the forced air.  You can see my
brush cover here.  http://www.evalbum.com/1524

damon  

> Date: Mon, 30 Jun 2008 15:37:02 -0700> From: amp_phibian@...>
To: ev@...> Subject: Re: [EVDL] The AMPhibian is alive.> > >
Yeah the old Yale seems to be doing the job very well. I'm glad you helped> steer me away from something
smaller. I'm looking for ideas for a ducted> motor enclosure to keep her dry and cool. Do I need anything
more than a> box with a fan? Any idea of how many CFM's I should shoot for? Even with> it geared at 16 to 1 I'm
still spending a decent amount of time creeping> around trees at low rpms, and skid steering at slow speeds
is probably> drawing some major amperage. I need some gauges to see what I'm really> doing.> John> > >
Hi-Torque Electric wrote:> > > > Hey John> > > > I always enjoy seeing a motor I've done get on the road (in your
case on> >
  or off 8^) EVen more so when it's an old motor given a new life.> > > > Anyway, looks like she bips along fairly
well, thanks for the video link,> > fun stuff. Looks like I can add AMPhibi!
 an to my list of "things" I've got> > motors in 8^)> > Cya> > Jim Husted> > Hi-Torque Electric> > > > > > > > > >
_______________________________________________> > For subscription options, see> >
http://lists.sjsu.edu/mailman/listinfo/ev> > > > > > -- > View this message in context:
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Bob Rice | 1 Jul 2008 01:37

Re: Towing DC motors

   Hi Bob;

    Hell! That's how the TA got their NEW subway cars from the builders, 
back when we actually BUILT stuff in our USA! they came without brushes in 
the motors. Upon arrival new brushes were put in the motors and they were 
shoved alongside a 3rd rail and lived happily ever after.

   You did right! The motor is free wheeling, no power in or out, in the 
pair, probably one truck of your Car?You can pull the motor effected right 
OUT iof the car for repairs. But of a project, though, although we got 
pretty good at swapping out trolley car motors at Branford.(Shoreline 
Trolley Museum, now) Check us out,sport's fans.It's fun when ya got the 
TOOLS for the project!Car lift jacks etc.

   Just go lightly on the 2 motors left! No racing, etc<g>!A few changes on 
the motor tap switches set's ya up to be a 2 motor car. well, ya know that 
already? The NYC TA didn't skimp on motor power!Probably 200 HP EACH?

     Seeya

     Bob
----- Original Message ----- 
From: "Robert MacDowell" <bobmac@...>
To: "Electric Vehicle Discussion List" <ev@...>
Sent: Monday, June 30, 2008 7:03 PM
Subject: [EVDL] Towing DC motors

> What happens if a DC traction motor is spun free, without either
> powering it or attaching a regenerative load to it?   Can the back EMF
> generated actually damage the motor?  Now, what if the brushes are
(Continue reading)

Joe | 1 Jul 2008 01:40
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Re: Towing DC motors

WHAT WOULD HAPPEN IF oops caplock,
anyway  what would happen if the brushes were left in?

Bob Rice wrote:

>   Hi Bob;
>
>    Hell! That's how the TA got their NEW subway cars from the builders, 
>back when we actually BUILT stuff in our USA! they came without brushes in 
>the motors. Upon arrival new brushes were put in the motors and they were 
>shoved alongside a 3rd rail and lived happily ever after.
>
>   You did right! The motor is free wheeling, no power in or out, in the 
>pair, probably one truck of your Car?You can pull the motor effected right 
>OUT iof the car for repairs. But of a project, though, although we got 
>pretty good at swapping out trolley car motors at Branford.(Shoreline 
>Trolley Museum, now) Check us out,sport's fans.It's fun when ya got the 
>TOOLS for the project!Car lift jacks etc.
>
>   Just go lightly on the 2 motors left! No racing, etc<g>!A few changes on 
>the motor tap switches set's ya up to be a 2 motor car. well, ya know that 
>already? The NYC TA didn't skimp on motor power!Probably 200 HP EACH?
>
>     Seeya
>
>     Bob
>----- Original Message ----- 
>From: "Robert MacDowell" <bobmac@...>
>To: "Electric Vehicle Discussion List" <ev@...>
>Sent: Monday, June 30, 2008 7:03 PM
(Continue reading)

Ryan Stotts | 1 Jul 2008 01:41
Picon

What's the price on these 12 V ThunderSkys?

Hawker shapes, I think the 3rd one has the power we need:

http://www.thunder-sky.com/products_en.asp?fid=66&fid2=82&page=1

Some more but they are big like semi truck batteries:

http://www.thunder-sky.com/products_en.asp?fid=66&fid2=82&page=2

A BMS for 29 lithiums sure is simpler and cheaper then 9,000
cells.....  Not to mention wiring it all up.  Let alone, building the
pack.

Bob Rice | 1 Jul 2008 01:47

Re: Towing DC motors

  Hi Bob;

   Again, my pix FINALLY downloaded! Wow! She's an' oldie! SURE it's from 
NYC TA? I see it ran LAST on SF's Key System, over the Bay Bridge, LONG 
before BART! General Murders PROBABLY helped kill the Key System?Hence the 
pantograph, on the roof.We  had ancient woodies like that on the El trains 
here, on the Least Coast, going back to STEAM powered El's! When electric 
came they were converted to electric, and lived on into the 60's NINETEEN 
60's! Living long enough to be saved by loving trolley fans.If there are any 
holes for Third rail paraphalania, on the truck frames?Surviving 
brackets?The NYC TA was 3rd rail from the get go, 104 years ago!This would 
be a dead givaway?

    Good to see OTHER RR guyz on here.

      Seeya

      Bob 


Gmane