[TowerTalk] TB3 Thrust Bearing Binding

[Roger (K8RI) on TT]

What material is the mast?  If it's Al the expansion may cause binding 
with the mast pushing up.  I believe you said the second bearing was 
used only for removing the rotator.

With 2 TB3s tight on an Al shaft they could be pushing against each 
other.  Normally the bottom bearing would have the bolts locked  with 
them just touching the mast.  The Ham series including the tail twister 
are designed to run with a positive load.

The problem could be the rotator, or bearings.  Lots of choices.

73

Roger (K8RI)


On 7/30/2015 5:17 PM, Kenneth Goodwin wrote:
>  From all indications with the outside temps reaching 100 degrees F, one or
> both of my two TB3 thrust bearings seems to be binding.  All TX2 Tailtwister
> rotator electrical data measured from the ground matches my baseline
> (resistance), I can hear and feel the brake release and the voltages applied
> to the TX2 motor windings are normal but until this morning when it got into
> the 80's - it wouldn't budge at all.  I use one thrust bearing on the top
> platform and a second as a means to remove the rotator if ever needed and
> keep the tangential loads off of the TX2 rotator.  I believe this happened
> the day before and it was in the same position (332 degrees).  Usually when
> the 40 meter beam fails to rotate, the TX2 brake mechanism is binding even
> with the Green Heron RT-21 rotation algorithm (small rotation the wrong way
> before rotation to the commanded setting).  Is heat a feasible failure
> mechanism for a Rohn TB3?   Anybody else ever run into this problem?  Ken
> K5RG
>


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