[TowerTalk] Prop pitch rotor identity?

[K7LXC@aol.com]

In a message dated 12/28/00 4:13:05 PM Pacific Standard Time, 
badkitty@gte.net writes:

> I have an old antenna rotator that I'm told is a prop pitch motor. About the
>  size of a small car transmission. One large wire coming out every 90deg.
>  Where does one find technical information for these things, and who to talk
>  to about service or rebuilding? I'm used to the "packaged" stuff and have 
no
>  idea where to apply power to this thing. The nameplate is illegible and it
>  has 24V stamped on it in ink.
>  
>  I've posted a couple pictures of it on the web if anyone's interested.
>  
>  http://www.radiohound.net/tower/rotor1.jpg
>  http://www.radiohound.net/tower/rotor2.jpg

    Yes - it's a prop pitch. There are two types of them - big and small due 
to their sizes relative to each other. I think what you've got is a big one. 
Since about 90% of prop pitches in use are the smaller version, I personally 
haven't messed with one.

    Is the motor the short part that has the shaft sticking out? I don't know 
if that's the motor or where the motor attaches. You may or may not have a 
drive motor. 

    What kind of tower do you want to put this in? What are you going to turn 
with it? 
>  
>  I'm looking at putting up a tower in the spring and summer months, so I'd 
at
>  least like to test it somehow.

    Hook up 28V +/- (ac or dc will work) to a couple of the wires and see if 
it starts up. If it does and then starts turning, it appears to be working. 

    The only way to see what the REAL condition of it is to open it up and 
peek inside. I bought a PP years ago and didn't do that; after a couple of 
years it quit because it was totally rusty inside. I had a real grody PP 
given to me to take to the dump but I thought I'd check it out before I 
chucked it. It was FANTASTIC inside so it goes to show you really can't tell 
without looking. 

    If it works and it's FB inside, then all you have to do is fabricate a 
tower mount, power supply and indicator system - none of which are 
insignificant tasks. Unless you're up for all the fabrication and work and 
your load is pretty large, it may or may not be worth it. 

Cheers,    Steve   K7LXC
Tower Tech

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