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Re: [TowerTalk] Rotor Cabling Query

To: "tower >> [TowerTalk]" <towertalk@contesting.com>
Subject: Re: [TowerTalk] Rotor Cabling Query
From: "Joe Subich, W4TV" <lists@subich.com>
Date: Sat, 3 Apr 2021 08:42:05 -0400
List-post: <mailto:towertalk@contesting.com>

On 2021-04-02 10:38 PM, Kelly Taylor wrote:
For such a length, would installing the motor-start capacitor,
> normally inside the control box, nearer to the rotor help?

The capacitor is not a starting capacitor.  The Hy-Gain motor requires
a phase shift between windings to run (a capacitor run motor).  The
direction of the phase shift determines which direction which direction
the motor rotates.

However, yes, installing the motor-run cap at the top of the tower will
reduce the voltage drop to the motor by about half, particularly if
the freed up wires are then used to double up on 5 and 6.

73,

   ... Joe, W4TV


On 2021-04-02 10:38 PM, Kelly Taylor wrote:
For such a length, would installing the motor-start capacitor, normally inside 
the control box, nearer to the rotor help?

73, kelly, ve4xt
Sent from my iPhone

On Apr 2, 2021, at 18:54, Joe Subich, W4TV <lists@subich.com> wrote:


A primary point/concern of my post is the length of the run on the temporary 
300 ft and to the final goal of 700 ft. What size of the conductors/wire/cable 
to utilize for the effort. Some part being
heavy duty 8 conductor rotor cabling in conjuction with splices
and/or runs of UF solid wire cabling from 14 gauge to 10 gauge such
as 14/3, etc. or other such ideas on conductor size.
You will need to figure out those trade-offs for yourself in your
particular installation.

The brake solenoid in the Ham IV/T2X is rated 24 VAC @ 5A.  The brake
uses wires 1 and 2 (the "heavy" wires).

The motor in the Ham IV/T2X is rated 20 VA @ 2.25 A.  The motor uses
wires 4, 5, 6, and 8 plus wire 1.  Rotation power is supplied to either
5 (rotate right) or 6 (rotate left).  4 and 8 are the capacitor
connection and the return in wire 1.

To energize the brake you have the voltage drop of (0.75 Ohm + the
resistance of wires 1 and 8) x 5 A.  To turn the motor you need to
overcome the voltage drop of (5.0 Ohms + wire 5 or 6 + wire 4 +
wire 8 plus wire 1) x 2.25 A.

I do not know how much voltage sag the brake or motor can handle before
they stop working reliably but I would not allow more than 2V drop as
a first estimate.

The typical "light duty" eight wire rotator cable is 2 x #18, 6 x #22.
DX Engineering says "suitable for most controller to rotator cable
runs of less than 125 feet."  You could probably back out the voltage
drops for a 100' run and use that as a "safe" limit.   The so called
"heavy duty" rotator cable is 2 x 16, 6 x 18 but is probably marginal
at 300 feet.


73,

   ... Joe, W4TV


On 2021-04-02 7:10 PM, CEPitts wrote:
I would like to hear from those in regards to ideas for the following. I know 
there are those who have long runs of control cabling for rotation, switching, 
etc. so I seek your ideas and advice.
I have a need for a temporary set up of a run that is 300 feet from the 
operating position shack/controller to the top of the tower controlling a Ham 4 
rotator. The final set up with be a run of 700 feet from tower to the operating 
position shack/controller
Would it be best to provide a disconnect near the connection point at the top 
of the tower with a short pigtail to the Ham 4, as well as a disconnect/splice 
point at the bottom of the tower, and a final run to the shack/controller?
Based on previous discussions/ideas tossed around here within the last 2-3 
weeks I would most likely take some ideas from the group in regards to utlizing 
trailer type connects/disconnects and also splices within the entire run.
A primary point/concern of my post is the length of the run on the temporary 
300 ft and to the final goal of 700 ft. What size of the conductors/wire/cable 
to utilize for the effort. Some part being heavy duty 8 conductor rotor cabling 
in conjuction with splices and/or runs of UF solid wire cabling from 14 gauge 
to 10 gauge such as 14/3, etc. or other such ideas on conductor size. A 
reasonable cost/maintenance perspective would be ideal keeping in mind going 
from the 300 ft to the 700 ft in the future and ease of said transistion. None 
of this will be buried, I have that part taken care of.
*(tower/rotor)*****short pigtail/run-->>>---*****(pigtail/connect splice)*****run to bottom of tower -->>>-->>>-----*** **(bottom of tower/connect splice) *****--->>>---->>>---*-****temp 
run*****>>---->>>>>>>---->>>>>>----->>>>>>>------>>>>>------->>>>> 300 ft expanding to 700 ft>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> (later to be the permanent 
run)>>>>>>>>>>>>>>*** **to connect/splice back to 8 conductor rotor cable ham 4 controller in shack.****
Besides possibly utilizing trailer type connects/disconnects I was also 
considering utilizing 8-10 conductor terminal blocks for splices/junctions etc. 
and I could possibly place those in weather resistant boxes at those points 
where required....What is the thought on that approach?**
Thank you for all the input/ideas and73! Ed K5OF in NC
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