The first thing I would do is replace the start Cap in the controller, they
are a common failure point.
https://www.amazon.com/dp/B00SK32TXA?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_4
Ron, WV4P
On Tue, Jul 29, 2025 at 10:34 AM Tony Brock-Fisher via TowerTalk <
towertalk@contesting.com> wrote:
> Potential Remedy for Stuck Hygain Tailtwister Rotators
>
> Tony Brock-Fisher K1KP
>
> Originally published in YCCC Scuttlebutt
>
> Should also apply to HAM-IV
>
>
> Everyone is probably aware that the T2X series rotators get stuck.
> Common knowledge has it that the brake wedge gets stuck, and to fix it,
> one can 'rock' the rotator in the opposite direction to get the brake
> unstuck, then move in the desired direction. This 'T2X rock' is a
> standard part of many automated rotator controllers like Green Heron and
> Rotor-EZ.
>
>
> But often this does not work for my rotator. I have replaced the rotator
> and still had the problem. I replaced a thrust bearing above the rotator
> and still had the problem.
>
>
> The problem recurred during the RTTY contest. I had a chance to play
> around with it and accidentally learned something that may lead to a
> cure. Thinking that sometimes the brake got stuck and sometimes it
> didn't, it seemed like there was something marginal about it. Maybe if I
> just drove it a tad harder it would work. So I hooked my rotator
> controller (standard Hy-Gain, with Rotor-EZ mod) up to a variac, with
> the idea of feeding it a slightly higher line voltage. And low and
> behold, I discovered that when in this 'stuck' state, the rotator
> control box (and rotator) brake drew **LOTS** more current from the AC
> supply than usual. When I finally got it unstuck, retracting the brake
> drew a normal amount of current. The critical observation was that the
> current draw was **drastically increased** when the brake was stuck.
>
>
> So here's my working hypothesis:
>
>
> The rotator gets stuck, when the gear backlash and motor are forcing the
> wedge against the sides of the wedge channel and the grooves in the
> bottom housing. (Bear in mind that the cheaper Hy-Gain rotators use this
> gear ratio as the primary brake). One would think that releasing the
> brake (which is actuating the solenoid) and rotating the motor in the
> right direction would release this load and allow the brake wedge to
> retract. However, the solenoid is an inductor. The inductance changes as
> a function of position. In normal operation, the brake solenoid quickly
> retracts, and the moving iron core completes the magnetic circuit,
> resulting in a high inductance, which limits the current in the brake
> circuit. With the brake wedge stuck, the solenoid is stuck in it's low
> inductance position. The circuit consists of a transformer, switches,
> the rotor cable, and the brake solenoid. The only thing that limits the
> current is the inductance of the solenoid and the resistance of the
> cable. So when the solenoid is stuck extended, it's inductance is very
> low and tons of current can flow. This high load current on the
> secondary of the power transformer saturates its core and reduces the
> voltage available for the motor to start moving. Therefore the motor
> cannot start to move to release the solenoid. Catch-22, everything is
> stuck.
>
>
> My experiment:
>
>
> I added a simple switch in series with pin 2 of the rotator cable so I
> can open the brake solenoid circuit. When the rotator gets stuck, I
> /open that switch/. This allows me to activate the motor to do the 'T2X
> rock' without allowing the stuck brake solenoid to load down the
> available voltage. I do a quick back and forth with the motor with the
> brake engaged. Then I close the switch, which allows the brake solenoid
> to retract. Voila! It moves again. So far, this has worked several
> times. Obviously, if attempting to move the motor with the brake stuck
> doesn't hurt anything, moving the motor with the brake engaged won't
> either.
>
>
> So the common knowledge about stuck T2X rotators may be incomplete, and
> it might make sense for automated rotator controllers to do the 'T2X
> Rock' with the brake solenoid de-energized.
>
>
> Try it and let me know if it works for you!
>
>
>
> p.s. The transformer does have a thermal cutout, which will open if it
> gets too hot, then close again on cool down.
>
>
>
>
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