Re: (ET) Update

[David C Robie <mycroftxx1 juno com>]

We called that 'dead short' stop 'motor plugging' and it's suppost to be
very bad juju for motors.   But it's the way that GE stops the deck
blades pretty much instantly when it's contactor drops out.  And it don't
hurt deck motors.  I did it before retirement on some robotic items such
as gearmoters running an underwater arm with grab and 3 axes of motion
and it didn't hurt em.    It only hurts Jerrys (ouch !).    Just don't
stand up when you drive, guy. 
      Seriously, it could be of use to decelerate the tractor in higher
tranny gears as she would normally do in lower gears.  Take out the short
(go ahead, ask 'short what?')  but in it's place put in a kinda hefty low
value resistor such as an old electric iron turned on 'high or 'steam'.
This could be area of experimentation that could improve Etractordom, as
we all know how useless and fast wearing down that Peerless disc brake,
designed for a much lighter tractor is in high gear or even third..  Let
that back EMF instead of stopping her dead slow her down faster than just
an open circuit there would.  To stop her in a high gear now we got to
'stage down' thru the electrical speeds way ahead of her stop. This way
would make 'stop' have some (not ultimate, as per Jerry) 'power off'
braking action too.
     This is not true regen, as true regen uses the back EMF to charge
the battery.  Very little charge could come from a tractor but on a
fullsize road EV it can increase range a few percent and in city stop n
go driving saves a lot of wear on the brake linings of a heavier than
normal vehicle.
     If it Twer me, would play with that a little bit.  A lot of
inventions happened because someone did something wrong and good things
came out of it. Wasn't the telegraph invented that way?  And Irish Spring
soap?

Dave
Weymouth MA




On Sun, 6 Aug 2006 14:59:57 -0400 "RJ Kanary" <rjkanary nauticom net>
writes:
>           Once again.....Permanent magnet motor ? You will have to 
> reconfigure the armature contactors so that there is no longer a 
> dead short across the armature when the contactors are not 
> energized.When I was young and uneducated on such things, I used a 
> set of armature reversing contactors from a large frame tractor on 
> my E-10. 
>          {I found the clutching and gear shifting rather tedious 
> maneuvering around obstacles on the lawn. }      
>          Did I get an education when I moved the directional switch 
> to its neutral position !  
>         I never rectified that I just got used to it.My Dad 
> OTOH,never DID get used to it. <VBG>
>   ----- Original Message ----- 
>   From: Jerry Rhodes 
>   To: Elec-trak Mail List 
>   Sent: Sunday, August 06, 2006 2:33 PM
>   Subject: (ET) Update
> 
> 
>   Afternoon all, lovely here in NW Ohio..sure beats 95 deg. Well got 
> 2 things to bring up 
> 
>       1A.. Got the NI EGT 120 running..nice fwd/rev left/rite PTO 
> works...BUT HOW DO U shut OFF the regen braking on the motor??? 
> after about 75' down the driveway I put her in neut and pulled 
> myself off the hood back into the seat ...that puppy STOPs**NOW** 
> man can we change that?? My E14 dosn't do that..
> 
>       1B..went to clean her up, pulled the batty cable off ( neg 
> frt/rear cable) an layed it up on the edge of the frt batty box and 
> she danced around (small sparks) not good, for sure not good..read 
> cable to frame/dash reading 24.8 vdc..not good..put cable on post 
> ... no spark, cable off read post to cable 36.9 vdc ...so I have 
> short to frame...need to check ALL wiring..any ideas to start? later
> 
>       2. update on ET Swapfest/Show...later today
> 
>   Jerry NWO   
> 
> 
>
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