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Re: [TowerTalk] US Tower Dayton AC Motor issue

To: TexasRF@aol.com
Subject: Re: [TowerTalk] US Tower Dayton AC Motor issue
From: "Scott McClements" <kc2pih@gmail.com>
Date: Sat, 13 Sep 2008 19:16:08 -0400
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Hi Gerald,

Thanks, I've gotten many off list replies. Most said to try replacing
the starting capacitor first.  But I few had mention to check  the
start circuit throwout switch. I will say that I did have to clean
wasp nests from inside the control box, esp. off the relays (why do
they like relays?). I'll check that out.

I pulled out the capacitor and there seems to be a little liquid (or
something)  that has leaked out of it. Since the capacitors seem
cheap, I'll probably just get one, but that is another issue. I was
looking at Grainger, they have a bunch in stock. The number on my
Dayton motor is 6K622N.  I haven't found anything on the web telling
me what I need, but the cap dimension is  3 3/8" X 2",  594 MFD (made
by philips).   I didn't find anything with this MFD range in this
dimension (most of this value were 4 3/8" high instead).  Where is a
good source for this guy?

Thanks,
Scott, WU2X


On Sat, Sep 13, 2008 at 7:04 PM,  <TexasRF@aol.com> wrote:
> Scott, you have described a classic case of an open start winding circuit.
> The most common cause in this part of the country is mud wasps building a
> nest around the start circuit throwout switch, causing the contacts to not
> make connection. The second most common cause is a defective start capacitor
> but this usually noticeable because of swollen areas on the end of the
> capacitor.
>
> The motors I have worked on have four long screws that clamp the end bells
> to the motor body. Removing these screws allows one to trmove the end bells
> and gain access to the throwout switch to examine and clean.
>
> Make note of all the wire colors and locations so you can return to the same
> electrical arrangement after fixing the problem.
>
> Hope this helps.
>
> 73,
> Gerald Williamson K5GW
> General Manager, Texas Towers
>
>
>
> In a message dated 9/13/2008 2:01:14 P.M. Central Daylight Time,
> kc2pih@gmail.com writes:
>
> Hi,
>
> I am in the middle of getting a used US Tower ready to put up. It has
> the MDLP1000 unit with the Dayton 1HP motor. Without the belt on the
> output shaft of the motor (free), I am unable to get it motor going
> full speed. It will just hum, spin slowly (like 1RPM) and blow the
> break within 3 seconds. I am able to spin the motor up to speed by
> hand and then hit the switch and it will spin up to full speed. The
> output shaft on motor spins freely and easily.
>
> I have a 50 foot run of #10 back to the service entrance on a 20 amp
> breaker.  Nothing else is on that breaker.  Without the motor I see
> 120V coming into the control box at the tower. When I hit the switch,
> the voltage drops to 107.5 Volts and the amperage draw is 52 amps. It
> will actually hum and slowly spin for about 3 seconds until the
> breaker blows. I am using a fluke clamp on amp meter. Not sure how it
> can pull 50 amps for 3 seconds through that 20 amp breaker, but that
> is another story.  If I check things on the main breaker, I see the
> voltage drop from 120 volts to 110 volts and 55 amps when I start the
> motor.
>
> If I spin up the motor by hand and the motor spins up to normal speed,
> it draws 9 amps (still with the belt off - no load on it).
>
> So I have read about voltage drop problems people have, but geesh, I
> am running #10 right to the breaker and its 50 feet long.  Do I need
> heavier cable or is it something else? Like maybe the starter
> capacitor in the motor?  Its a 1HP Dayton 6K622N model ("Farm Duty
> Capacitor Start"). I could probably run 220 VAC / 30 Amps to it as
> well, if this would help (and is possible).
>
> Thanks,
> Scott, WU2X
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