I could be
wrong about this {Imagine THAT.}, but I feel the reasoning behind the
armature resistance is best explained thusly..............
There is going to be a MAJOR inrush current nailing the armature at
every start if these resistors are not present.That can't be an
approach to long life and prosperity. :(
Secondly those armature resistors provide a smoother, more controlled
launch, but were never intended to be a long term speed selecting
device.
[ Turns a whole lotta watts into BTUs.]
(And if you ever get to operate an E-20 / I-5 with the eight speed
Apollo Era controls that third armature resistor makes a noteworthy
difference in smoothness and precision of control while maneuvering.)
RJ
stupidemail5 lycos com wrote:
I have been running my E12S with no control and 2 switches
all winter. A DPDT center ON wired so that down is off, middle is
start/low and up is high. DPDT center OFF in place of the f/r relay.
Yes it is a death machine, but it made me think that wiring the whole
thing with a couple of self holding relays it could be done safely.
they actually make delay relays that would make it slick.
My thinking is that I never use lower speeds except for current
control, and now some snow blowing. I choose the gear I want and pretty
much go full speed. The lack of torque with the resistors makes the
lower speeds pretty lame.
I could probably implement with the stock switch array.
The RTN deal is the only hard part, and actually with self holding
relays and a 3PDT center off for field reversing that should be OK. The
third pole would be in the string for the main start relay so it would
drop out when you go to the center position.
Probably a 'go fast' button for field weakening
KG
On Feb 10, 2011, David Brandt
<ev_dave13 yahoo com> wrote:
|
I used a curtis to power the armature and ran the field
through a rheostat (E15). The field is usually at full power and it
runs plenty fast for mowing in D1. If I want to race it (or run back
to the garage when it starts raining), I can weaken the field as much
as I want.
The field at full strength only draws about 2 amps. A
relatively small rheostat is all that is needed.
--- On Thu, 2/10/11, David Plamondon <roberttroll hotmail com>
wrote:
From: David Plamondon <roberttroll hotmail com>
Subject: (ET) Thinking out loud - Controller
To: elec-trak cosmos phy tufts edu
Date: Thursday, February 10, 2011, 12:49 PM
If one wanted to replace just the
first three speeds, and not worry about field weakening, is there a
simple controller that could do this? To my understanding the
controller options that are available have special "software" that
allows for the weakening. If i didnt want that, what possible options
are there? I would basically be looking to replace the ribbon resistor
and card on a E15 - possibly a E20. Thoughts?
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