Re: (ET) Question for the EE types

[Rob Brockway <GEtractor Yahoo com>]

I put an extra heavy capacity rheostat in my e12 m (with an e-20 
driveline).  I also put a latching relay circuit in.  Every time I want 
field weakening I push a button and adjust the rheostat to the speed I 
want with my eye on the power meter.  Every time I put the control in off 
or reverse in un latches the relay.  This way I don't forget end leave it 
on.  Before I put a Curtis speed control I did not allow weakening until 
the voltage to the armature was close to 36 volts.  I have used this set 
up for about 10 years.

It works well for finding a good speed at the right power level and using 
regen going down hill.  You don't get a free lunch however.  At reduced 
field you get less torque and the max starting torque is very reduced.

Sent from my iPad

On Jun 24, 2012, at 9:03 PM, "Christopher Zach" <cz alembic crystel com> 
wrote:

> To be honest, just how much energy would you save? I have found that 
> speed
> is not stable going up and down hills in speeds 1-3 (E20, 1-2 E15) so I 
> just
> select the right gear and spend 99% of my time in speeds 3 and up (where 
> it
> is most efficient)
> 
> C
> 
> -----Original Message-----
> From: Charlie [mailto:medievalist gmail com] 
> Sent: Sunday, June 24, 2012 3:55 PM
> To: Rob Brockway
> Cc: Elec-Trak
> Subject: Re: (ET) Question for the EE types
> 
> Thanks, Rob, I was wondering about that; the toaster is obviously 
> capable of
> carrying huge amps, but the little wire-wound ceramics under the dash 
> don't
> look like they could handle much current at all.
> 
> Today I discovered that my varistor is exploded.  Remarkable that the
> I-5 still works, although certainly not optimally.
> 
> --Charlie
> 
> On Sun, Jun 24, 2012 at 9:27 AM, Rob Brockway <GEtractor yahoo com> 
> wrote:
>> Keep in mind the power loss with resistors used with the field is 
>> trivial.
>  Resistors used with the armature is significant.
>> Rob
>> 
>> Sent from my iPad
>> 
>> On Jun 22, 2012, at 5:43 PM, Charlie <medievalist gmail com> wrote:
>> 
>>> In at least three places in the Elec-trak's original circuitry, 
>>> voltage is being dropped by resistors which waste a portion of the 
>>> power as heat.
>>> 
>>> In theory, could a circuit be designed to substitute a less lossy 
>>> voltage converter (buck-boost maybe?) using the original wiring and 
>>> connectors?  A "plug in" replacement for that card full of resistors 
>>> under my dashboard, or a "bolt in" replacement for the toaster?
>>> 
>>> I'm aware that an Alltrax would make this unnecessary, but I've got a 
>>> late model I-5 in reasonably cherry condition and I don't want to 
>>> install a potted controller (admittedly if I had a field reversing 
>>> relay I'd drop in an Alltrax in a heartbeat).
>>> 
>>> --Charlie
>>> 
>>> _______________________________________________
>>> Elec-trak mailing list
>>> Elec-trak cosmos phy tufts edu
>>> https://cosmos.phy.tufts.edu/mailman/listinfo.cgi/elec-trak
> 
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