Re: [EVDL] EPRI TVA VW electric bus

[zvwbus via EV]

A friend of mine in Belgium got one of these buses, and he had his local
forklift repair shop put it back on the road.  He mentioned that it handled
like a forklift.  Probably has to do with the ton of batteries.

This is not exactly a conversion.  The bus has been electric since new, and
was built by Volkswagen in Germany as part of a collaboration with some
other German companies including Siemens and Varta.

The earlier Volkswagen buses used reduction gears, but that ended in 1967. 
This bus uses a double-jointed independent rear suspension system.  I have
removed the axles so that I can test the bus on the ground without it
moving.  Before I removed the axles, I turned them both at the same time
which forced the transmission to turn the motor.  Reverse is achieved by a
switch on the dash.  I assume that reverses the polarity.  The negative
cable into the controller from the battery pack is isolated from the frame
of the bus and the body of the controller.  

I am aware that this is ancient technology.  I do plan on having a more
modern drivetrain in this or another bus at another time, but for my my
purposes at this time, I want to have this one as original as possible with
the likely exception of the batteries.  I view the batteries as a relatively
easily solved thing, although I have not decided on which direction I go
with that.  I want this to run with its stock drivetrain for its historic
significance.  It is pretty cool that VW was developing electric vehicles
over 40 years ago.  This bus in this configuration won't get driven
regularly.  I recently bought an electric VW Karmann Ghia from my friend,
John Bryan, who pointed me towards this list/forum as he mentioned that it
was very helpful for him and an overall great community.  The Ghia needs new
batteries (hopefully the same ones that I use in the bus).  The Ghia will be
a regular driver for me in the coming years.  




Electric Vehicle Discussion List mailing list wrote
> Glad you found it informative.
> 
> These motors are frequently called "forklift motors", probably 
> because, well, they were used in forklifts... Your Siemens controller 
> is likely a "forklift controller", assuming that the conversion 
> company didn't design one from scratch and have Siemens construct it 
> (them). It might be possible to find more information on that unit by 
> haunting industrial material handling equipment sites and forums.
> 
> 
> If the van is limited to second gear, how is reverse accomplished? 
> Shutting down the motor to reverse it's rotation seems like a 
> nightmare for an on-road vehicle, would make parking a real hassle. 
> Stop motor, reverse fields, restart motor, repeat as necessary. Uhg.
> 
> If you get it running, you might want to consider changing the 
> transmission setup. I use all  four gears and reverse. 4th isn't 
> useful until about 50 MPH, but a lot will depend on your final drive 
> ratio. Don't some (all) of the old VW vans have reduction gearing 
> after the differential?
> 
> Something to consider: It would be fairly easy to design and build a 
> substitute controller with an Arduino, some instrumentation-grade 
> op-amps and a couple hundred lines of code. The days of using 
> TTL/CMOS discrete components to build logic and control circuits is long
> past.
> 
> Overloaded yet?



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Re: [EVDL] EPRI TVA VW electric bus

[zvwbus via EV]

Electric Vehicle Discussion List mailing list wrote
> OK, this topic has induced me to resubscribe to the EVDL, it's 
> probably been 20 years since I was officially signed up. I've 
> occasionally passed replies through several members (thanks Lee, 
> thanks David), but maybe it's time to get out in the open.
> 
> What you have there is similar to the shunt-wound motor in my 
> factory-conversion SCT Rabbit from 1981. I can't tell you anything 
> about the controller, but the motor is very familiar.
> 
> Shunt wound motors differ considerably from series wound motors. For 
> one thing, they have regenerative capabilities as a native behavior. 
> The field windings are energized separately from the armature (they 
> are also known as "separately excited" motors). I'll leave it to you, 
> or others to do the research on the technical principles involved, 
> but suffice it to say, the armature runs at 100% voltage (direct 
> connection to the batteries through a contactor), while the motor 
> speed is controlled by ~weakening~ the field voltage. That's right, 
> ~weakening~!
> 
> You can not run this motor by simply applying a voltage and watching 
> it spin. There is a startup sequence, which consists of applying full 
> voltage to the field windings, and a current-limited (via resistors 
> or other current limiters) voltage to the armature. This causes the 
> armature to come up to an idle speed slowly (4-5 seconds), at which 
> time the controller applies full battery voltage to the armature.
> 
> These motors have poor stall torque, so it "idles" when not actually 
> driving the vehicle forward. Mine idles at about 1,800 RPM (120 volt 
> nominal battery supply). This is with full field. As the field is 
> weakened (by a PWM or "chopper" circuit), the motor speeds up.
> 
> This type of motor allows a fully functional "one pedal" driving 
> style. Step on the accelerator to speed up and let off to activate 
> *very* powerful regenerative braking. I see 200+ amperes while 
> downshifting through all gears (I realize that your vehicle is locked 
> in 2nd). Using the service brakes is not necessary except in an 
> emergency or to come to a complete stop.
> 
> Before you do anything else on this van, you MUST check a few things 
> beforehand.
> 
> On the end of the motor that you have pictured is a conical shroud 
> held on by clips/clasps. This is the brush end of the motor. There 
> are eight armature brushes under this shroud. If the van has been 
> siting for any length of time, you would be well advised to pull this 
> shroud and check to see that ~all~ of the brushes are free to slide 
> in their holders *and* that none of them are stuck to the armature. 
> also clean out any dirt/dust/cobwebs/insect or rodent nests you see!
> 
> Now, as for your test to see if it ran. Did you twist the key over to 
> the "start" position? Because the motor has a start sequence, there 
> must be some method of engaging the field voltage and armature 
> current limiting circuits. Installing a fresh 12 volt accessory 
> battery will likely be necessary, as the controller obviously 
> requires a low voltage supply in addition to the traction battery.
> 
> Until last week, I had a web site with extensive documentation on my 
> SCT Rabbit, including information on the motor, etc. Some of this may 
> be useful to you, so drop in to the archive.org Wayback Machine and 
> check some of the PDF files that got saved in a snapshot of my site 
> from  seven or eight years ago:
> 
> http://web.archive.org/web/2009054159/http://www.mrsharkey.com/SCT/index.html
> 
> Glad to answer and questions you have, sorry to be completely 
> ignorant about your controller.


Awesome, thanks so much for the information.  This is a great start towards
making this thing work.  When I was in college, one of my computer science
professors explained that the people in the factory put the magic smoke into
the electronic components, and it is our job not to let the magic smoke out. 
I have taken this to heart when working on electric stuff like this which I
know very very little about.  Thus I am unwilling to just put voltage to a
component like the motor and see what happens.  Normally, when I go to work
on something I have a massive technical library to draw upon, but in this
case, I am starting out in the dark and this has shined some light.  

On the operational characteristics of this motor, by the field having full
voltage at stop (or just more voltage than the armature), it overpowers the
armature and creates drag buy forcing the system to generate electricity,
and when the armature has more voltage it uses the battery power to turn. 
Is this correct?  Not that it necessarily helps in getting it running, but I
like to know how/why things function.

I turned the key on, and to the start position a couple times, but I got
nothing to indicate than any electrons were flowing anywhere in the system. 
I figured that the start position was just a 

Re: [EVDL] EPRI TVA VW electric bus

[zvwbus via EV]

Electric Vehicle Discussion List mailing list wrote
> Curious, did they raise the floor to fit the battery box? You could 
> probably get a 40kWh lion pack in there, if it goes all the way through 
> :)
> 
> Peri

The floor is the normal location for a VW bus.  There is massive storage
space for batteries.  There is an extra frame below the normal frame because
of the extra weight of a ton of batteries.  There are sliding doors on both
sides of the bus so the battery pack can be pushed through with a new
battery pack.  

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Re: [EVDL] EPRI TVA VW electric bus

[zvwbus via EV]

 


 


 


 


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[EVDL] EPRI TVA VW electric bus

[zvwbus via EV]

This is my first post to this list/forum, so please bear with me.  I am a
collector of old VWs, and I had long known that VW had developed EVs in the
'70s, and I always wanted one.  A friend of mine came up with one a few
years back, and I bought it from him.  It is a 1979 VW bus which was
originally owned by the Tennessee Valley Authority.  They bought and tested
ten of these vehicles in 1979.  (NASA tested one in '77).  I know many
things about VW buses, and I am fairly mechanically inclined, but I know
next to nothing about this drive system.  The bus has been off the road for
20+ years and I am trying to get it going with as much of the original
drivetrain as possible.  I hope that someone has some knowledge of this
system and how it works.

The sparse technical literature that I have shows that the Motor is: Siemens
1 GV 1161-Z and the controller is a Siemens 6 RB 1000-1BA

The literature says that it has regenerative braking.

The transmission is set in 2nd gear permanently.  I turned the axles, and
the motor turns.

It is designed to run on 144 volts, but it is supposed to work from
110v-170v.  I strung 11 12v auto batteries together and got 137v  The volts
make it to the connection at the controller, and I turned the ignition
switch on and press the accelerator and nothing happens.  This is where my
expertise runs out.

I can run a multi-meter, and I know how electricity works in general, as I
can and have made every part of the electrical system work on any number of
old 6v Volkswagens.

The questions I have are:

1) Does anyone here have working knowledge of an ancient Siemens controller? 

2) How does the regenerative braking work?

3) the literature says that it is a shunt wound DC motor.  Can I test the
motor by supplying voltage directly to it?  If so, how much voltage should I
use to test it?

Thanks in advance.








  

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