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[TowerTalk] Prop Pitch Hash

To: <>
Subject: [TowerTalk] Prop Pitch Hash
From: (
Date: Wed, 18 Jul 2001 14:11:21 EDT
In a message dated 7/18/01 6:25:34 AM Pacific Daylight Time, writes:<< 
    Does any one know the best Value components for curing PP hash from the 
 brushes?. And are any of you using power diodes across the DC inputs?.
 Regards Clive GM3POI
This is a simple by passing problem and .1 ufd 600V ceramic disks work just 
fine.  Use one of the existing solder points on each Brush for one of the of 
the capacitor leads. What are the power diodes supposed to do?

I want to emphasize that every effort should be made to make sure no water 
gets around the spline shaft coming out of the housing recess.  I drill drain 
holes at the bottom of the recess in case some does.  There are holes in the 
housing case on the small PP Motors They must be sealed with a plug and 
epoxy.  The oil seals are 60 years old but are replaceable.  I will be making 
pictures available how I keep the water away from the output shaft.  Back in 
the late 40's I had a tapered cover over it but water can blow in under it.  
Water got in my first PP Motor and rusted some bearings.  The oil is drained 
out that is in the housings and all I had at the time was Vaseline for a 
grease.  I was able to remove, clean up the bearings and replace them.  
That's the only problem I've ever had of 8 of them.  They were mounted 
horizontally on the airplane motor shaft with a cover over them.  The 
original oil should be removed as it will slip by the oil seal at the bottom 
and get into the motor.

As I've mentioned before PP Motors don't have ALL the problems ALL the other 
rotators have.  The latest rotator thing I've been reading about is some K 
factor I think it was.  You don't have to worry about all this with a PP 
Motor.  The main problem with commercial rotators is they are under rated to 
last 5-7 years--on purpose.  Replacing a rotator high on a tower is a regular 
and expensive procedure for many and a big job often with a crane in 
particular in bad weather.  This is a major and regular expense which takes 
money that could be used for newer designs of antennas or coax that seems to 
go bad more often than it should.  If you buy one get one "1-2 sizes larger" 
than recommended by the Mfg for your antenna.  Perhaps you could extend your 
rotator trouble free time for 10-14 years?  From what I hear they seem to go 
bad just before or during contests in the winter.  Do you have any idea 
what's it's like not to have a single rotator problem or additional expense 
in over 50 years?  NOTE! I do recommend the PP Motor be taken apart and 
checked at least every 50 years or for each new owner.  I do have some that 
are due for a "Semi Century 50 Year Check" and perhaps refreshing the grease 
with a low temperature grease like "Ams Grease."  Who knows the grease could 
wear out with all the use it gets in a speeded up rotator?  I hate to rub it 
in--but I will.

If you take one apart and remove the Planetary gear remember this.  There is 
a "witness mark" usually a "0" on the top row of a double gear in the 
Planetary that all have to be "out" when inserted into the housing ring gear 
or you won't be able to get the bell gear to slip over it.  In a Medium PP 
Motor I worked on for a friend it had a tricky witness mark on it's 4 gears.  
It had "0's" and "2's" on the same gear 90 degrees apart for unknown reasons. 
 They had to be "alternated."  The Bell gear wouldn't go over it with all the 
"0's" or "2's" out.  That was the only one I've seen with the double witness 

I was informed that many of these PP motors were made by Electrolux Vacuum 
Sweeper Co.  I had a Electrolux Vacuum Sweeper that has lasted over 50 years 
also.  The son of the Electrolux Sweeper Co Walter Groff was a gun friend of 
mine and I never knew this at the time while I was using the PP Motors.  He 
was a student of the greatest of all Double Action Shooters Ed McGivern as I 
was.  He told me that during the Depression he and his dad considered buying 
Smith&Wesson but felt the "anti-gun" feeling then was too high.  That was 
indeed unfortunate as the junk S&W has sold would not have happened.  

Another company who's ham gear has survived the "Test of Time" is Collins.  
It's the "Prop Pitch Motor Ham Gear of Today".  It still works and sells for 
high prices.  I examined the Collins Quality Assurance practices and although 
they weren't that of Deming they did the job.  They had an extensive program 
of testing parts before acceptance for one thing as did Rickover did for the 
Nuclear Submarine Program.  It was the "Art Collins Quality Assurance Program 
for Pride of Ownership, Performance, Design, Longevity and Retained Value."  
My Collins KW-1 and 75A1 have only had one part replaced in each one.  K7GCO

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