Hi Jim -
In defense of the PPM's - Have you ever opened one up and seen how they're
built ? I would guess that any motor shop could rewind the "coils". The
bearings and brushes are obtainable. The gear box, if tended to, should last
forever, or at least have replacements available for longer than any of the
current rotators will be supported by their manufacturer or NEMA. They may
be an overkill for many of the jobs they're asked to do, but my guess is
that they will outlive most of us who are using them.
Gene / W2LU
----- Original Message -----
From: "Jim Lux" <jimlux@earthlink.net>
To: <towertalk@contesting.com>
Sent: Tuesday, September 06, 2011 4:08 PM
Subject: Re: [TowerTalk] Heavy Duty Rotor
> On 9/6/11 12:09 PM, Bill Gaines AD8P wrote:
>> Our local club is looking for a very heavy duty rotor that will fit
>> inside Rohn 45. It needs to turn a very large 3 el 40 and 6 el 20 on the
>> same boom. What is out there in cyber space?
>>
>> Bill AD8P
>>
>
> M2 and Alfa-Spid both have rotors in the 3000 in-lb torque area. Not as
> much as a prop pitch, I suspect, but pretty large all the same.
>
> Bringing up an interesting question.. Some day, all those prop pitch
> motors will die (or it will be 2050, and 100 year old Kurt will have
> retired). There's also the "replacement if damaged" scenario, always
> tricky when you've used some sort of surplus that's 60 years old as the
> basis for your widget. I can see all sorts of calamities that could
> destroy a rotor beyond repair.
>
>
> So, what do people today use for turning those big TCI LPDAs, for
> instance? Does TCI manufacture rotors or do they buy from someone else?
>
> I imagine one could just order an off the shelf gear motor of the
> appropriate ratings. It would be expensive (probably more than $1000),
> but it would be a standard component with standard fittings, so if you
> had to replace it, it's just a trip to your local motor dealer to buy a
> replacement NEMA flange motor or gear box.
>
>
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