[TowerTalk] prop pitch rotors

[NPAlex at aol.com]

Rob,
 
First the prop pitch motor is a 24-28 v motor and will run close to 1rpm at  
those voltages.  The brake is energized when sufficient current passes  
through the coil. But it is recommended to remove the brake components as they  are 
not needed.  To do this remove the motor from the gear housing, to make  it 
easier to handle, by tapping the large retaining NUT/Ring (castle nut) by  
tapping it CCW using a soft punch.  A little lubricant helps.  With  the motor 
loose the end cap of the motor can be removed exposing the brake  components.  
remove the brake disk and other parts of that assembly.   Replace the end cap and 
you are ready to test.  There is a common lead  and the other leads provide 
CW or CCW rotation.    In my system  the power supply is nominally 32V at the 
base, and can deliver 20amps.   More than enough.  But allowing for voltage 
drop is a consideration in the  selection of a power source.  Green Heron and 
K7NV have combined to supply  a very good Power supply, control box and read out 
package.  I have use  Prop pitch motors as a rotator for over 35 years with 
out any failures.
 
regards,
Norm W4QN

=========================================================
Message:  8
Date: Mon, 12 Mar 2007 16:37:27 -0700
From: Rob Frohne  <frohro at wwc.edu>
Subject: [TowerTalk] Prop Pitch Doesn't Turn
To:  towertalk at contesting.com
Message-ID:  <1173742647.22646.19.camel at frohro-d600>
Content-Type:  text/plain

Hi,

A few years ago I purchased a couple of what I  believe are small prop
pitch rotors.  Now that I have a need for them, I  am trying to figure
out how to test them.  One of them I was able to use  some of the ideas
on K7NV's web site to get turning with my 13 volt power  supply.  It
turns at about 1/3 rpm.  The other prop pitch seems to  have a brake in
it, and I have been able to get the brake to click down  (though it seems
that it takes a lot more current than the other one's motor  does), but
the motor doesn't move.  I have removed the aluminum housing,  but not
the motor yet.  I think I have the right wires as there are  three which
look like they were used before, and according to K7NV there is a  common
and the other two determine which direction it should turn.  I  think
this prop pitch was used to turn a Sky Needle in the past.  Anyone  have
any advice?

73,

Rob, KL7NA
-- 
Rob Frohne, Ph.D.,  P.E.
E.F. Cross School of Engineering
Walla Walla College


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