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Christopher Zach | 1 Aug 2011 01:18
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Re: Inrush Current

Jeff Major wrote:
> In your case, the mower, attachments and motors were all designed by GE to work in that application.  Was the
Etek motor designed for across the line starting?

They're all just motors, series, shunt, and PM motors. Nothing too 
specific there. All of which are swinging at least a blade, as much as a 
very heavy auger on startup. It's possible the Etek is far more fragile 
than a 30 year old Elec-trak mower motor, but that sounds kind of odd.

As a further point of reference, the E8 tractor literally has a switch 
that comes on with no resistors or anything. Motor spins up, belt clutch 
drives the tractor. To date we have not heard of any E8 motors with 
de-magnitized field magnets.

Chris
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Bill Dennis | 1 Aug 2011 02:24

First Faux Pas

With the new battery pack in the MetroLectrical, I've been driving the car
to work this week to shake out the system.  Until Friday, everything was
going splendidly.  Then on Saturday, I was about half way to work and came
to a halt at a stop sign.  When I stepped on the accelerator to start up
again, though: nothing.  Car wouldn't budge.  I took out the key, opened the
hood and looked around.  Couldn't see anything amiss.  So I got back in the
car, inserted the key, and would you believe it: the car took right off.
"Wow," I thought, "must have been nothing"...until the I came to the next
stop sign, that is.  Stopped, stepped on the accelerator to take off again,
and nothing.  No contactor clack.  No Curtis squeal.  There I sat, dead on
the street, waving other motorists to go around me, heart racing, trying to
figure out what was going on.

Finally, it dawned on me what was happening.  Just to get the car running
last weekend, I haven't installed the DC/DC converter yet.  Instead, I put
in a string of four old LCP 90Ah cells as the 12v battery.  When I installed
them, they had 14V.  On Saturday morning, they still read 14V, about 3.5V
per cell.  Shouldn't be a problem right?  Plenty of charge left.  

WRONG!

These cells are so un-stiff that the smallest amount of current was dragging
them down to a low voltage--too low to pull in the main contactor.  But
after the car had rested for a few minutes, the voltage had recovered to the
point where it would pull in the contactor.  Of course, once the contactor
as engaged, only about 6V was required to keep it closed.

So, I let the car sit for a few more minutes, then inserted the key, started
off, and drove back home, making sure I never took my foot off the
accelerator.  Ran a changing red light or two, but made the 1700 ft. climb
(Continue reading)

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Cruisin | 1 Aug 2011 03:53

VW IRS Tranny Rebuilt FS in Calif.

VW IRS Tranny from 1970 beetle rebuilt $275.00 without exchange plus shipping
cruisin@...

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Jeff Major | 1 Aug 2011 03:55
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Re: Inrush Current

Hi Chris,

I am somewhat familiar with ElecTrak motors.  Those GE PM motors are 2 pole with real commutators.  No doubt
ceramic magnets.  Thick ones at that.  A far cry from B&S Etek design.  Now I don't know if there will be a demag
problem, or commutation arcing, but it is illogical to assume there will not be based on your experience
with the GE motors.  

Regards,

Jeff M

--- On Sun, 7/31/11, Christopher Zach <czach@...> wrote:

> Jeff Major wrote:
> > In your case, the mower, attachments and motors were
> all designed by GE to work in that application.  Was
> the Etek motor designed for across the line starting?
> 
> They're all just motors, series, shunt, and PM motors.
> Nothing too 
> specific there. All of which are swinging at least a blade,
> as much as a 
> very heavy auger on startup. It's possible the Etek is far
> more fragile 
> than a 30 year old Elec-trak mower motor, but that sounds
> kind of odd.
> 
> As a further point of reference, the E8 tractor literally
> has a switch 
> that comes on with no resistors or anything. Motor spins
(Continue reading)

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Cruisin | 1 Aug 2011 03:58

18650 Sanyo Li-ion cells 3.7v 2.6ah solderable $2.00 each

Solderable 18650 used Li-ion cells 3.7v 2.6ah made by Sanyo removed from
battery packs hardly used.
Cost is $2.00 each cruisin@...

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jcmassey | 1 Aug 2011 03:58
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Re: First rides

Quoting David Roden:

> On 31 Jul 2011 at 19:09, James Massey wrote:
> 
> > I set the motor up with contactors to be able to switch between
> > fully-series and divided-series in order to play around with the
> > speed/torque characteristics of the motor.
> 
> Sorry, I'm not familiar witih the terms "fully-series" and "divided-series."
> Can you please explain what you mean?  Is there some unusual characteristic
> of this motor?

G'day David, All

Forklift drive motors usually have the fields connected completely in series
1-2-3-4 then to the armature. Road-vehicle motors connect the fields divided 1-2
paralleled with 3-4 before going to the armature. Forklift motors are maximised
for torque at lower (continuous) amps, on-road motors are optimised for higher
revving characteristics and (intermittent) higher amps. 

I started with a 10" diameter Japanese forklift drive motor of unknown
characteristics (other than 48V/4.5kW), so I knew that I'd need to be doing some
playing around with it. Since I was setting it up to be able to externally
divide the fields, instead of internally, it was simple to use a reversing
contactor set to get switch-over between the two connection sets.

I just wasn't expecting the back-emf of the motor to build so quickly, I get a
momentary 600A+ peak as I pull away, rapidly falling to 400A as the volts flies
up across the motor, and very soon have over 100V across the motor and the amps
falling off, and struggling to get 3000RPM on the flat.
(Continue reading)

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Cor van de Water | 1 Aug 2011 04:08
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Re: First rides

Roland,
The OEM Honda Civic 155-13 wheel makes about 914 revs per mile
so 40 MPH is about 36560 revs per hour or 609 revs per min (RPM)
With the motor turning at 2500 RPM, the gear reduction is
2500:609 = 4.10
In contrast to what you explain, this means that the motor makes
4.10 revs for each turn of the tire.
This sounds different than I am used to, but I did not check
the drive ratios on a Civic.
James,
I too am curious what the divided-series operation means.
It sounds like taking part of the field out of the loop to
create field weakening by powering a lower number of the
field windings?

Regards,

Cor van de Water
Chief Scientist
Proxim Wireless Corporation http://www.proxim.com
Email: CWater@...    Private: http://www.cvandewater.com
Skype: cor_van_de_water     XoIP: +31877841130
Tel: +1 408 383 7626        Tel: +91 (040)23117400 x203 

-----Original Message-----
From: ev-bounces@...
[mailto:ev-bounces@...] On
Behalf Of Roland Wiench
Sent: Sunday, July 31, 2011 6:54 AM
To: Electric Vehicle Discussion List
(Continue reading)

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Mike Nickerson | 1 Aug 2011 04:33

Re: First Faux Pas

I did almost exactly the same thing when I first started driving my
conversion!  When I got it, there was a little Black & Decker 12V charger
for the accessory battery.  I didn't realize it died a short time later.
It's very frustrating to have 14 kWh in the traction cells and no way to
engage the contactor so you can drive home!

I called my wife and she brought the tractor battery.  I placed it in the
passenger area and I made some quick jumper cables to snake under the hood.
I still have the jumper cables in the trunk of the car so I can jumper 4
cells to make 12V in a pinch.  I installed an Elcon DC-DC converter soon
after.

Mike

> -----Original Message-----
> From: ev-bounces@...
[mailto:ev-bounces@...] On
> Behalf Of Bill Dennis
> Sent: Sunday, July 31, 2011 6:24 PM
> To: 'Electric Vehicle Discussion List'
> Subject: [EVDL] First Faux Pas
> 
> With the new battery pack in the MetroLectrical, I've been driving the car
to
> work this week to shake out the system.  Until Friday, everything was
going
> splendidly.  Then on Saturday, I was about half way to work and came to a
> halt at a stop sign.  When I stepped on the accelerator to start up again,
> though: nothing.  Car wouldn't budge.  I took out the key, opened the hood
> and looked around.  Couldn't see anything amiss.  So I got back in the
(Continue reading)

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AMPhibian | 1 Aug 2011 04:47
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Re: Li-Ion BMS video: Top vs bottom balancing

Purchased in 2009, installed in 2010, about 4K miles on them, so relatively
new.  I don't drive much and it's been off the road since Dec.

David Nelson-5 wrote:
> 
> How old are your cells and how many full cycle equivalents have they done?
> 
> 

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bruce parmenter | 1 Aug 2011 05:28

Re: Great little VOLT story out of Florida

Great? No.
Good? It was OK ... I have seen much better
about the Ampera pish (GM's Euro version).

It will be interesting to people, for whatever 
reason ,feel good about lugging around an ice with
their light 30 mile pack.

This video is of a Volt pish driver in FL that as 
of the video creation date had only driven it 1000 
miles.

The driver could not buy a Volt pish in FL, so he 
arranged to get one from a NY dealer and have it 
shipped to his FL home. He mentioned in the video 
that one day he went 90 miles.

...
When I heard that, I wanted a look at what public 
charging there was in FL:

http://www.blinknetwork.com/locator.html
Blink does not show any public EVSE in FL

http://www.afdc.energy.gov/afdc/locator/stations/
The Fed Government only shows a handful of EVSE

http://www.mychargepoint.net/find-stations.php
Coulomb Chargepoint and 
http://www.recargo.com/search?search=florida&filters[]=1772&filters[]=tsl&filters[]=oc1450&filters[]=oc
(Continue reading)

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Gmane