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Thanks Frank,
I spent a bit of time yesterday thinking on the angle of motor rotation
problem,
especially with the advice of Vance, that its better to rotate the motor
from up
to down rather than reverse it as it takes time to ramp up &
down.
Also there would be large voltage spikes doing this.
I came up with a simple link that will get me over 200 degrees of
rotation,
however I'll keep it to 180 degrees.
The link is a C shape or a half segment of a circle.
One option for mounting the link is to have a circular plate fixed to the
motor
rotating rod. The C is mounted with it's arc upward & one end is
attached to
a pin near the outer edge of the circular plate. The other end of the C is
linked to
the linear actuator. This is OK for the forward motion of the actuator but
for the
backward motion a small pin needs to be fixed on the circular plate below
the C
somewhere near the middle of it's arc. The C "levers" on this on the return
stroke
so if the pin rotated it would be better. This has worked fine with bits of
cut out
cardboard pinned together. I'll go to balsawood next.
I'm using the magnetic membrane potentiometer for angle indication &
are linking
this to a simple circuit built from a kit, that displays with LEDs (like
Jens made)
Hopefully I'll post this on site in a weeks time.
I like the idea of banking the sub like the "Maltese Falcon", I'm aiming at
that too.
If you're sight seeing in a small plane you dip the wing to see what's
below you.
They aren't too expensive & are built for water.
Regards Alan
----- Original Message -----
Sent: Saturday, July 24, 2010 4:18
AM
Subject: Re: [PSUBS-MAILIST] linear
actuator- thruster range
Hello Alan. My side mount electric linear actuators travel through a 120
degree arc. It goes from straight vertical to 30 degrees down. With the
forward/reverse capability of the Minnkota motors it should give me the
ability to hover, move straight up and down in the water column, and of course
maneuver left and right in close quarters. The side actuators are controlled
separately so it is possible to angle one down and the other up, making it
possible to accomplish " banked " turns with or without supplying power
to the side thrusters.
The rear actuator has the same arc which positions the motor
mounts/rudder assemblies for a relatively tight turning radius. The two
side-by-side assemblies are tied together so they rotate in tandem, although
the motor supply for each rear thruster is separate so it's possible to power
the motors one forward/one reverse.
I don't expect to use this option much but actual testing in the water
will prove how useful this is.
The purpose of having completely separate circuits, battery banks,
fuse blocks, controllers, thru-hulls, etc. for each motor ( 4 ) is to isolate
each motor circuit completely in case a problem should develop in any one
circuit. This is in keeping with the " redundancy" approach to having a
back-up system available where ever possible.
As far as the indicator for dive plane and rudder position, I'm leaning
toward using Vance's idea of a strictly mechanical system of cables and
indicator arrows placed in front of the view ports. It eliminates a whole
electrical circuit system for three actuators with the associated wiring,
lights, fuses, and thru-hulls required for an electrical position indication.
The cables will all be covered safely under the fiberglass fairings and with
nothing more than a shot of grease, should be reliable and low
maintenance.
Frank D.
Frank D.
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