[TowerTalk] Why a Prop Pitch?

[NPAlex at aol.com]

John,
I can only guess from your comment that you have not had any experience  with 
a prop pitch motor used as a rotator.  There are several reasons that  one 
would use a prop pitch motor.  
One was cost, as surplus motors were available at very reasonable prices.  
They bring some premium now do to limited availability.  
Another reason was power, or Torque. They can handle very heavy  loads.  
Another reason is size and shape.  They fit inside relatively small  tower 
cross sections, with no projections beyond the tower sides as some of the  new 
models do.  This makes them very ideal for crank-up towers as all is  within 
the tower envelope.  
The electric motors (nom. 24vdc) are held in place with a large castle ring  
nut, spin that off and the motor unplugs for easy maintenance.  The gear  box 
removal is on a par with most rotator types.  
One of the drawbacks however is direction sensing.  That has to be  added.  
Historically that was done by use of Selsyn tx/rx coupled to the  mast.  Today 
both M2 and Green Heron Engineering provide controllers with  pulse counting 
direction indication.(K7NV design used with GHE, check out his  web site).  The 
GHE controller has many features and provides ramp up and  down which is 
useful with large arrays.
 
I have had the same prop pitch motor in service for nearly 40 years,  trouble 
free.  
 
summarizing - Power (torque) and Size.
 
Norm W4QN
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Message:  3
From: John Cowan <w0tmm at yahoo.com>
Subject: [TowerTalk] Prop Pitch  Motor
To: towertalk at contesting.com

Why would you use a prop  pitch motor as opposed to a regular rotor?
John  W0TMM
-----------------------------

Message: 4
Subject: Re:  [TowerTalk] Prop Pitch Motor
To: w0tmm at yahoo.com,  towertalk at contesting.com
wasnt he going to turn some serious snort? After  making about 6 trips 
up the tower to work on rotors this last year Ive  wondered why I didnt 
go to them in the first place. A new spid is working  great for me know 
though.
73 Mark W0NCL