Re: (ET) E12 lost power

[Chris Zach <czach computer org>]

The words "very slight amount of movement" answer the question; the 
field is not being powered.

You know this because the Elec-trak motors are not really 100% shunt 
motors. They have a small series field in series with the armature. It 
is this field that causes an E20 to have slightly less power in reverse, 
go a bit faster in reverse, and the big reason why you *NEVER* do field 
weakening in Reverse (the field is already slightly weaker due to the 
series field opposing the main field because reverse on an E20 reverses 
the armature and not the field like an E15)

That little series field alone will mean that your motor is redefining 
the term "field weakened". It's all alone, and is not enough. I'd bet if 
you put the whole thing in neutral and hit the gas you would hear the 
motor start to spin way up. Don't do this; you will just overspeed the 
motor.

As people have said, check the field wires and the relays. Somewhere 
something came loose. I'm sure the armature is ok, but you will wreck it 
if you keep trying to move the tractor sans field.

Chris


Richard Zachary wrote:

> Put in new solenoid coil at 1F just 3 weeks ago and everything seemed 
> fine.  Mowed weekend before last and everything was like new.     Went 
> to mow today and seemed fine for two seconds, it went about a foot and 
> half, and then POW! everything stopped.  99.9% of power lost (very 
> slight amount of movement possible both forward and back, but the power 
> usage gauge was pinned to the highest point).  Noticed an electric 
> smell, and found a lot of heat up front.  Three coils in front of the 
> charger where RED and giving off loads of heat.  One of the large wires 
> coming off coil 2F was also hot.
> I tried the PTO switch and the mower deck by itself ran just fine, 
> leading me to believe that the batteries are OK.
> Pulled the motor off and tested the resistance across the two main 
> connection posts.  The meter went to the top indicating a short across 
> these posts.
> Had the motor redone with new bearings, brushes, rotor cut in April.
> Question is, could it be something other than the motor?
> Thanks in advance for any advise,
> Richard "Zack" Zachary
>
>
>
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