[TowerTalk] Thrust Bearing Problem...maybe

[thompson@mindspring.com]

Could be one of several problems...and I have had them all...

First, could be as simple as that dreaded T2X problem with sticking. pushing
the beam is similiar to rocking it back and forth or going the other way
then coming back.

Second, might be binding between the rotor and the top of tower. Or the
rotor is not quite on center.  I had this problem even with a properly
drilled plate.  I had to lock the plate down in the plumb position.
Tristao/now US Tower plates just sit on the cross bars.

Third,  the starting capacitor can be a problem.  Found out that the old one
worked Ok when I switched to the next size up control cable (was about 160'
from control box to the rotor motor.   I find the capacitor is either OK or
bad usually.

Fourth,  have the right bearing for the size mast.  I have always used
Fafnir bearings...they are very rugged altho not really designed for outside
use.  I grease up the case and use what they recommend for the bearings.
The big hex set screw is designed to be tightned until the mast is straight.
Tighten too much and the bearing binds the mast.  I have three fafnirs
now...one for schedule 40 water pipe (short masts only) that is 1.9" OD.
One is for 2" OD steel and the one in use is for 2.25" OD.  The tower lets
you use any mast from 1.5 to 2.5" so make sure the bearing is also
centered!!!

I had a beam slide down to sitting on the bearing....this binds the bearing
and causes sticking and grinding,,,so lift the antenna off the bearing a
couple of inches.  I put a big muffler clamp above the bearing so this will
not happen again.

If the bearing is working correctly even a small TV rotor will rotate a big
array...just what out for the direct downward force.

Dave K4JRB



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