Re: (ET) field weakening on E15 and moving dirt

[Jim Coate <jbc coate org>]

As far as I know, Bill Gunn still requires check or COD for orders... I
sent him a check just last week :-)

To restore the studs for the tach pickup, do they need to be magnetic?
What type of sensor does it use?

On the field weakening, first off I'm surprised that it is set to the
full 48 volts (vs 36 volts of original design). But be that as it may,
you might want to make a set up where you know when you are starting to
weaken the field... max torque (good for say pushing dirt around) is
with full field. If you weaken the field too much for a given load,
you'll see ridiculously high armature currents. Or just pathetic
response as the controller will limit the armature current.

I think most golf carts that have sep-ex motors use a sep-ex controller
that takes care of the field along with the armature all in the one
package. But I'm curious to hear what others have to say.



agp@??? wrote:
> I have examined the circuit that GE used for field weakening and it 
> appears
> simple enough.  But I think it would be better to use some kind of
> semiconductor switch for my 48V system.  Do any of you Trakkers know how
> golf cars have their field weakening set up?
> 
> One other note.  The Club Car controller that is being used has an input
> for a Tachometer.  The tach was apparently functional at one time.  But 
> the
> "studs" that were glued on to the pulley of the motor have fallen off.  I
> thought of having a machine shop just use some small bolts as the studs. 
>  I
> believe the output of the tach would then be a pulsed waveform with
> rectangular shaped pulses of magnitude no greater than 5V.
> 
> On the positive side:  I was able to push some dirt today! 
> ...  I think I'll just buy one from Bill Gunn with the
> order I'm placing on Monday.  Does he accept VISA?  (Prior emails in the
> archive said he only takes checks or COD.)


_________
Jim Coate
1992 Chevy S10
1970's Elec-Trak
http://www.eeevee.com