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Re: [TowerTalk] Rotor Cabling Query

To: "Joe Subich, W4TV" <lists@subich.com>
Subject: Re: [TowerTalk] Rotor Cabling Query
From: Kelly Taylor <ve4xt@mymts.net>
Date: Fri, 2 Apr 2021 21:38:54 -0500
List-post: <mailto:towertalk@contesting.com>
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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