[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: (ET) ge pulling
From the motor design standpoint, a Klixon is "meant" to sense motor
overtemperature longer term...high loading, lack of cooling air, etc....
It's similar to an "idiot light" on your car...when the oil pressure light
comes on you should have pulled over 5 miles before....that kind of
concept.
I can't see it on a schematic as a "sensor" for over temperature so it
must be used as a short term over current device. Klixons are bi-metallic
units and current/temperature expands one metal against the other until
the "click" apart opening the circuit. Cooling allows it to reset.
For pulling, you could probably by-pass it but not a bad idea to "feel"
the motor frame for high temperatures between runs. Motor insulation is
made of organic compounds in these old motors and averages the peak
temperatures out. Motor commutation at high amps/less than top speed
should be
okay.
I've been trying to get GE to quote a drive suitable for Elec-Traks that
is used on golf carts. GE still makes all electric golf cart motors but
not all the controls
as OEM's source some of their own these days. Will keep the post posted.
...Walt
-----Original Message-----
From: elec-trak-bounces cosmos phy tufts edu
[mailto:elec-trak-bounces cosmos phy tufts edu]On Behalf Of Markus
Sent: Thursday, June 01, 2006 9:44 AM
To: jbc coate org; 'Elec-Trak'
Subject: Re: (ET) ge pulling
Hi Guys,
I was referring to the internal heat sensor/switch that is built into
the motor. Wondering if that would only protect the field windings or
also open in time before the armature gets too hot. I could immagine that
for longer term high usage this is adequate protection as the heat has
time
to propage thoughout the motor. For very brief very high power demands
(like
when doing a pull) I am not so sure that it would tripp early enough.
I have taken the klixon units apart in the past and can confirm what
you guys say. It is a simple thermal breaker. To a small degree it does
take
motor temperature into account as it is being mounted on the motor but that
is negligible, especially for short term very high load.
Markus
> -----Original Message-----
> From: elec-trak-bounces cosmos phy tufts edu
> [mailto:elec-trak-bounces cosmos phy tufts edu] On Behalf Of Jim Coate
> Sent: Donnerstag, 1. Juni 2006 15:29
> To: Elec-Trak
> Subject: Re: (ET) ge pulling
>
>
> The Klixon is most definitely an external thermal circuit breaker; it
> has no way to measure the motor's internal temperature. It
> should take
> ~10 seconds to trip at double the current rating, and ~1 second at
> 5x-10x the rated current. As it is thermal based, it will also be
> slightly influenced by ambient temperatures (ie trip sooner
> on a hot day).
>
> In general I would never recommend bypassing protective
> devices, but...
> if I was doing a short pull and knew the motor would then have a long
> cool-down time....
>
>
> Tim Humphrey wrote:
> > I know its not right to reply to yourself but...
> >
> > I just read through some of the digest regarding the Klixon.
> >
> > It seems that yes it is just a circuit breaker. It also
> seems to be rated at around 80-100amps depending on your model
> > of ET.
> >
> > For the purposes of "pulling" I would definately recommend
> bypassing it and also not worry too much about burning yup
> > your motor.
> >
> > Why? Because on my sawmill, I have the drive motor (an
> E-15 drive motor) wired directly with no protection. I will
> > occasionally cut a log 12"-14" diameter. During this cut I
> am drawing a continuous 125-150 amps for a minute or two,
> > when finished the motor is warm to the touch. It usually
> has 3-5 minutes to cool while I reposition things for the
> > next cut.
> >
> > A full minute for a tractor pull would seem like an eternity.
> >
> > I suspect that a tractor pull would have less of a duty
> cycle and thus be less danger to the motor than my sawmill.
> >
> >
> >
>
>
> --
> Jim Coate
> 1970's Elec-Trak's
> 1997 Solectria Force
> 1998 Chevy S-10 NiMH BEV
> 1997 Chevy S-10 NGV Bi-Fuel
> http://www.eeevee.com
>
>
> _______________________________________________
> Elec-trak mailing list
> Elec-trak cosmos phy tufts edu
> https://cosmos.phy.tufts.edu/mailman/listinfo/elec-trak
>
_______________________________________________
Elec-trak mailing list
Elec-trak cosmos phy tufts edu
https://cosmos.phy.tufts.edu/mailman/listinfo/elec-trak