On 4/3/21 5:42 AM, Joe Subich, W4TV wrote:
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
Yeah, but you're still looking at 2 strands of 700 ft of AWG10 or AWG8
to operate the brake. Or, all sorts of gyrations to increase the voltage
out of the controller (I seem to recall posts some years back looking at
how high can you make the supply voltage, or using boost transformers
on the controller outputs to overcome the losses - sure, if you've got a
box of 5A 25.2V filament transformers you picked up surplus at a ham
fest - go for it.)
Viz the cost of wire these days, it would probably be *cheaper* to
remote the controller to the base. You could put a Rpi, little relay
board to control the *stock* controller and a webcam to look at the
front panel for under $100, although I think a green heron style
controller might be better in the long run.
If you don't want to do wifi, Fiber optic Media Converters from the
standard RJ45 network jack run about $40-50 each (you'd need one at each
end of the run) and the fiber cable would be about $100. So for $200,
you'd have 100M or 1G ethernet to your tower. (prices are from fs.com -
a reputable low cost supplier)
500 ft of AWG 10 stranded is $150. You'd need 3 spools so $450. And
that's just for the first 2 conductors.
You could go aluminum and go a couple gauges bigger and that might
actually save some money.
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