----- Original Message -----
From: <K7LXC@aol.com>
Sent: Friday, April 28, 2006 7:37 AM
> It's becoming clear that while there are sometimes problems with the
> rotator (M2 2800)
> itself, the emerging reliability culprit is the mast clamp. The Orion one
> has so little actual clamp-to-mast surface area that it is unable to hold
> any
> large sized array. The mast clamp on the BigBoys seem to have their
> limits as
> well.
>
> BTW I'm having some more suitable clamps for the Orion fabricated
> and they'll be available for sale in the near future. If you're going to
> have
> an Orion/MonstIR installation, you'll need one of these.
>
The problem with the mast clamps furnished by M2 for the 2800 rotator has
been discussed on Towertalk before, however not fully enough to provide
solutions or explanation of the problem.
The M2 literature includes "Ductile iron, massive, toothed mast clamps". As
Steve mentions the 'toothed" clamp has little area in actual contact with
the mast. Further, the massiveness may actually be detrimental because the
"ductile" iron cannot conform much to the mast? Mechanical
engineers--comment please.
The M2 specification claims "Wind Area Capacity.......35 sq. ft.". Sounds
great but no wind speed is included so that the specification is useless?
The M2 specification claims "Braking Torque.......17000 in. lbs.". That is
about 5 times the starting and rotating torque specification which would
also seem great. But how does one determine the torque that is being
applied to the rotator from the wind and/or the moving antenna load? I can
see quite a bit of movement at the tips of the MonstIR in light winds
indicating some play in the gearing which can allow a "shock" load to the
clamp. Again, Mechanical engineers--comment please.
The M2 literature includes " DO NOT "PIN" THE MAST TO THEIR POSITIONER.
PINNING THE MAST WILL VOID THE OR-2800 WARRANTY.". The literature also
discusses that slip may even be desirable. What happens to the warranty if
a stronger mast clamp (not of M2 design) is used?
The M2 literature also includes the proper bolt tightening sequence. How
important is this and could improper sequence be the cause that some our
mast/clamps have slipped? However, the literature does not include the
proper bolt torque to apply for tightening.
I have two M2 2800 rotators so would like to get answers and solution to
this problem. I hope M2 will contribute.
k7puc
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