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Re: [TowerTalk] Prop Pitch Motor

To: "Tower and HF antenna construction topics." <>
Subject: Re: [TowerTalk] Prop Pitch Motor
From: "Jim Hargrave" <>
Reply-to: "Tower and HF antenna construction topics." <>
Date: Sun, 14 Mar 2010 22:48:39 -0500
List-post: <">>

I have a small PP. Comments embedded below

> -----Original Message-----
> From:
> []On Behalf Of Gene Fuller
> Sent: Sunday, March 14, 2010 9:58 PM
> To:
> Subject: [TowerTalk] Prop Pitch Motor
> What is the maximum DC voltage used successfully/recommended for
> one of the "small"  PPM's ?

I am running mine with a 24 volt battery charger transformer with a variac
on it.
The running voltage is about 15-18 VAC.

>  What speed was accomplished

Mine goes stop to stop in about 30-40 seconds. Depending on outside temp.
I crank the variac up a little in the winter when the rotor grease is
cold and down in the summer time.

> and how
> was the brush life at that voltage ?

Unknown. I have had it for about 45 years and the original brushes are still
I don't know how long the previous owner used it.

> 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.

Mine will run full speed at 24 volts DC. At that voltage it will go stop to
stop in about 20 seconds.
Way too fast for the TH6 and a 14 element 2m beam. It takes about 50 seconds
with a 12VDC power supply.

I use #12 Romex, However I have the rotor mounted 4 ft up from the tower
base, so the voltage drop is not an issue for me.
and use a drive shaft (Mast) up to the top of the 50 ft tower. The power
supply is mounted in a WX proof box about 2 ft from the rotor.
I have AC power coming from my Well house about 25 ft away. The rotor is
controlled by remote using 12 vdc relays in the antenna box. I also have the
antenna coax switching inside the tower box. The tower box is about 110 ft
from the operating desk. All my wiring/coax is underground in PVC pipes.

 Any suggestions will be greatly appreciated.

The PP was designed for 28 volts. I originally had the rotor at the top in a
previous QTH with about 75 ft of #12 wiring. It ran fine with about 20 volts
AC. I used # 12 220v Romex. All three wires are the same size in the 220
cables. Whereas the 120v Romex may have a smaller ground wire.

I would suggest you mount the rotor and then play with the power supply
voltages until you get it at the right speed. This will be easy to do since
you are mounting the power supply near the base of the tower.

   73's  Jim - W5IFP

> Thanks,
> Gene / W2LU
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