RE: (ET) pack not isolated from frame??

["T Humphrey" <thumphrey mynra com>]

But if you do this, then you connect the pack to the frame, 
through the lights. Exactly what you don't want.

Stay Charged!
Hump



> 
>
>-----Original Message-----
>From: Bob Murcek [mailto:rmurcek geisinger edu] 
>Sent: Monday, January 26, 2004 12:45 PM
>To: elec-trak cosmos phy tufts edu
>Subject: (ET) Re: pack not isolated from frame??
>
>
>Just had a thought about catching frame grounds early.
> 
>I've noticed that in industrial situations where 3-phase delta-
connected
>power (three hot wires totally unrelated to ground, no neutral) 
is used,
>electricians sometimes connect a light bulb from each of the hot 
wires to
>ground.  Since the three hot wires don't have a relationship to 
ground, the
>bulbs all glow equally running in sorta-series.  If there's a 
ground fault,
>i.e., if one of the hot wires gets connected to ground by 
accident, the bulb
>for that wire goes out.
> 
>We could do the same thing, I think.  Just connect two small 
(something that
>would take a least a quarter of an amp) 36-48 volt bulbs, one 
from the plus
>end of the pack to the frame, and one from the negative end of 
the pack to
>the frame.  Properly fused of course.  Maybe with one fed from 
the load side
>of the key switch so that they were only on when the tractor was.
>
>
>>>> Dave & Debbie Barden <daveb seanet com> 1/26/2004 8:38:50 AM 
>>>
>because of some red-orange paint I thought for a while it might 
be a
>wheelhorse 
>but the the GE symbol is there on the front grill.  there's no 
hole up front
>
>where the PTO plug may've been. The tractor has been painted JD 
green
>including 
>the name plate on top of the dash unfortunately and the data 
plate under the
>
>hood isn't there.  Unless I can get some info off the painted 
plate atop the
>
>dash I'm afraid all I'll have to go on is physical description.  
the
>tractor's 
>on the island and it'll be friday before I can get there again.
>
>thanks for the warning/confirmation that I've a dangerous 
situation that
>must 
>be fixed immediately.  I'm taking that to heart...
>
>dave
>seattle
>
>>       As my Dad, the electrician who had 30 years of experience 
with DC
>> operated overhead cranes would say, "Son, you've got something 
that's
>'gone
>> to ground'."
>>     {Actually, in most cases two items have to fail to make 
obvious
>> symptoms.}
>> 
>>     The most common culprits in the Elec-Trak(r) are.......
>> 1.) Armature resistor contactor bushings.
>> 2.) Armature terminal bushings on the traction motor, or brush 
rigging.
>> 3.) Lift motor.
>>      This situation is VERY dangerous, and must be investigated 
and
>repaired
>> immediately.
>>     I have never seen a tractor with the PTO outlet where you 
have
>described
>> it. Give us the numbers from the data plate, under the hood, 
and I think
>we
>> can puzzle it out.
>> 
>> ----- Original Message ----- 
>> From: "Dave & Debbie Barden" <daveb seanet com>
>> To: <rjkanary nauticom net>; <tcoate coate org>;
>> <elec-trak cosmos phy tufts edu>
>> Sent: Sunday, January 25, 2004 2:54 PM
>> Subject: pack not isolated from frame??
>> 
>> 
>> >
>> > I was working on my modified E15 (?) today, and while 
loosening a
>> connection on
>> > one the cable connections I grounded to the body with the 
wrench and got
>> an
>> > ugly juicy spark.  That doubly surprised me because I am 
always careful
>> around
>> > battery terminals and potential grounds but also because I 
thought that
>if
>> the
>> > pack was not grounded to the frame you wouldn't/shouldn't get 
current
>> flow??
>> >
>> > So what gives here am I under a mis-impression and showing my 
ignorance
>or
>> do I
>> > have a ground somewhere that I shouldn't have??
>> >
>> > Also since this tractor has been modified by the previous 
owner I don't
>> really
>> > know what model it is.  My E12S has the PTO plug up front on 
the left.
>> This
>> > one has the PTO plug down by my right foot.  Would this be an 
E15 or E20
>> or???
>> >
>> > thanks much,
>> > dave
>> > Seattle
>> > E12S
>> > E?? modified
>> >
>> >
>> >
>> >
>> >
>> >
>> 
>> 
>
>
>
>
>
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