Jim, I believe that the TR44 "brake" is basically a friction ring mounted on
the motor armature. When power is applied, the armature is pulled up into the
stator field to do its rotation duties. When in the no power position, the
armature drops to rest on a plate built into the motor assembly and though low
in weight/mass, it relies on the gearing to translate that to a sufficient
braking force. If this is worn, broken, or possibly oil-soaked, it slips.
Norm's or Craig (at Rotor Doc) can give you the difinitive answer. Your clamps
aren't slipping, it's (as you have observed) the brake. I used one of these
rotators - once - but never again just because of this problem. The "wedge" is
better (though it can hang up); the ultimate answer for 100% braking is a worm
gear.
73, Tom - WA2BPE
WB9UWA Jim Shaffer wrote:
> Hi All,
>
> Perhaps someone would confirm what I think I am seeing.
> I am using a TR44 rotor that was upgraded to Ham M by adding
> bearings to the race. It served me in the 80's with a TA33 on it
> which stripped the ring gear. Shortly after this, the ring gear was
> replaced by a stainless steel ring gear.
> Now to the present:
> I am using this rotor on my roof mounted 2m EME array consisting
> of 4, 20 foot boom yagis mounted 5 feet to the H frame from the reflectors.
> It is off balance and front heavy so is normally tied down when not in use.
> Last night a surprise winter storm brought substantial winds and I was
> surprized
> to have found the array turned about 45 degrees. I was further surprized
> that
> the meter tracked the position, so I returned it to its parked direction. At
> noon
> with the winds still up, I found that it had returned to a 45 degree off
> direction.
> I have never seen the wind turn this rotor before even though it does not
> have
> a brake. Is this normal for this rotor and should I be concerned for damage
> to
> the rotor or this the rotor just doing me a favor by directing the array
> into a less
> damaging direction?
>
> 73, Jim Shaffer, WB9UWA.
>
> _______________________________________________
> Towertalk mailing list
> Towertalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
|