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Re: (ET) Comparing E12 to E15



       The E-15 of course has more speeds, for more flexibility, higher top speed. It also has larger tires.more important, IMHO, is the fact that the E-15 has a more robust traction motor.More continuous power output, more endurance. 
        Since the later E-12 models have a PM traction motor, putting it to work with the E-15 controls would provide no advantage.
       The E-12S is essentially a "decontented" E-15. first, it has smaller tires. It has a wound field motor, a plus IMHO, over the later ones, but of course has no sophisticated field control.
         Both the E-12S and the stablemate E-15 of that era have the then 'state of the art'   SCR / UJT control system that never really impressed me from a reliability stand point . Add to that the problematic field reversing directional control, and you have a system that would not be my first choice for a tractor that sees heavy use, year 'round.
         So, the wound field motor from the 'S' model is a 'plus', but the armature reversing control used in the later models is again IMHO a durability 'plus'.Looks like a dead heat to me.
      If I've stomped on anyone's toes, I will apologize. These "IMHO" statements are based on the observations that I've made over the past twenty or so years of servicing these units.
 
----- Original Message -----
Sent: Sunday, February 20, 2005 5:00 AM
Subject: (ET) Comparing E12 to E15

Hi all,
 
I'm looking for feedback, especially from those who are familiar with both models, as to the advantages of an early AA-series E15 over a late JD-series E12.  My reference model is an E12S, which is an E15 without the field weakening circuitry. 
 
I ask this, because I have a "mostly-running" PM drive motor E12 (everything works but 3rd speed), and a mostly complete, but untested E15, that I could complete by taking parts from the E12, until I can obtain the needed parts elsewhere (and who knows how long that'll take).  The E15 is missing the charger timer and line cord (I use solar anyway, so don't need this), main power disconnect, and the field weakening and reverse relays on card #1.  Additionally, card#3 is broken at the mounts, but the traces seem to be ok. 
 
My E12S seems to be significantly more tractor than the E12.  Is the E15 a similar step above the E12S?
 
Thanks.
 
Tom


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