It's worth noting that these "modified" pp gearboxes are no longer capable of
doing the antenna rotation tasks usually asked of prop pitches. They trade off
torque and braking capability (holding in the wind) for an increase in
rotational speed. Please don't do this to a pp.
73,
geo - n4ua
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of TexasRF@aol.com
Sent: Monday, March 15, 2010 9:42 AM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Prop Pitch Motor
One of the fellows here mentioned a speed of 20 or 30 seconds for one rev.
An unmodified prop pitch motor takes almost 2 minutes per rev.
There was a mod published in CQ Magazine back in the 50;s showing how to
pin one of the planetary stages in the gear box to speed it up. Many users
did the mod and as a result, usually ran the motor on less than the rated
28vdc to reduce the speed to more like one rpm.
Before you commit to the voltage you might want to see if your unit is
stock or modified.
73,
Gerald K5GW
In a message dated 3/14/2010 10:20:32 P.M. Central Daylight Time,
TexasRF@aol.com writes:
Gene, the current draw at startup is a bunch higher than the running
current. Sorry, don't know how much higher.
You are probably ok with the 3 #12 wires but you might want to test it on
the ground before a final commitment.
As long as the motor starts, you will be in good shape and the extra
voltage drop will only help slow down the start up.
The prop pitch motors were designed for 28VDC so that is probably a good
voltage to use. The speed will be proportional to the voltage so lower
than
28 volts will slow them down a bit. They are already a tad on the slow
side
so use your own judgement.
73,
Gerald K5GW
In a message dated 3/14/2010 9:58:38 P.M. Central Daylight Time,
w2lu@rochester.rr.com writes:
What is the maximum DC voltage used successfully/recommended for one of
the "small" PPM's ? What speed was accomplished and how was the brush
life
at that voltage ?
I 'm building a power supply to put at the base of the tower and can
change the voltage from about 30 to 48 volts in 6 volt steps. Cable to
PPM will
be 100 feet of 3-#12's. I'm figuring about 0.5 ohms and about a ten amp
demand i.e. a 5 volt drop.
Any suggestions will be greatly appreciated.
Thanks,
Gene / W2LU
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|