Re: (ET) Ariens AMP Mower

[RJ Kanary <rjkanary nauticom net>]

<Reversing the low current field in 
a shunt motor is almost a trivial task, requiring only a small relay or 
small semiconductors. It makes much more sense to reverse the field than to 
reverse the armature. This is one of the advantages of a shunt or sep-ex 
motor over a PM or series motor.>


UNFORTUNATELY...........this is one of the areas that GE didn't get right.<G>

And judging from the number of trouble posts still popping up some thirty years later, it's STILL a major reliability concern.

GE DID learn their lesson. { There's that history thing again. :) }

Maybe 21st Century Technology would make this a 'trivial ' task , but again, from what I've seen and repaired...........<VBG>


RJ
The Luddite 

David Roden wrote:

I do 99% of my work with it in two speeds ...
    

Not here!  My property is hilly, uneven, and broken up in to little islands 
of grass.  I appreciate being able to creep the machine at times.  Am I 
typical?  Probably not, but I'm sure I'm also not the only one.

When you're designing an electric tractor from the ground up, I agree that 
the cheap way to go is to bolt the motor into an existing design.  There are 
advantages to using mass-produced, proven components.

However, an electronic motor controller is effectively a continuously 
variable transmission without the inefficiency of hydro drive.  The cost of 
a small DC motor controller adequate for a garden tractor is certainly not 
prohibitive, and much less today than it was 30-35 years ago.

  

just reverse the armature with big contactors instead of fiddling
around with the field. 
    

I don't understand why you suggest this.  Reversing the low current field in 
a shunt motor is almost a trivial task, requiring only a small relay or 
small semiconductors. It makes much more sense to reverse the field than to 
reverse the armature. This is one of the advantages of a shunt or sep-ex 
motor over a PM or series motor.


David Roden - Akron, Ohio, USA

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 
Note: mail sent to the "etpost" address will not reach me.  To send 
me a private message, please use the address shown at the bottom
of this page : http://www.evdl.org/help/
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =




_______________________________________________
Elec-trak mailing list
Elec-trak cosmos phy tufts edu
https://cosmos.phy.tufts.edu/mailman/listinfo/elec-trak