Ideally it would be great to have true 3 phase to the shack and I do not
mean open Delta which sucks.
Tom, k5bm
----- Original Message -----
From: <towertalk-request@contesting.com>
To: <towertalk@contesting.com>
Sent: Monday, August 02, 2010 11:57 AM
Subject: TowerTalk Digest, Vol 92, Issue 8
Send TowerTalk mailing list submissions to
towertalk@contesting.com
To subscribe or unsubscribe via the World Wide Web, visit
http://lists.contesting.com/mailman/listinfo/towertalk
or, via email, send a message with subject or body 'help' to
towertalk-request@contesting.com
You can reach the person managing the list at
towertalk-owner@contesting.com
When replying, please edit your Subject line so it is more specific
than "Re: Contents of TowerTalk digest..."
Today's Topics:
1. Re: Fwd: shack wiring (Paul Christensen)
2. Re: Fwd: shack wiring (Bert Almemo)
3. Re: Fwd: shack wiring (Charlie Gallo)
4. Re: Rohn 45 no guys (Robert Chudek - K0RC)
5. Re: Rohn 45 no guys (Robert Chudek - K0RC)
6. Boots (for climbing) (Ryan Jairam)
7. Re: Rohn 45 no guys (Grant Saviers)
8. Power Distribution (Jim Brown)
9. Re: Boots (for climbing) (Michael Goins)
----------------------------------------------------------------------
Message: 1
Date: Mon, 02 Aug 2010 11:12:39 -0400
From: Paul Christensen <w9ac@arrl.net>
Subject: Re: [TowerTalk] Fwd: shack wiring
To: "towertalk@contesting.com" <towertalk@contesting.com>
Message-ID: <4C56E067.4040102@arrl.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> ## I don't think so. The most that could happen is the input
> fuse to the xfmr would blow open.
Before, or after the person requires CPR?
The MGN is the return leg
> for the 7200/14.4 kv. Notice that the CT of the sec of the xmfr
> is also bonded to this same MGN . That's done...so each home
> that gets a neutral, also has the same neutral grnded to cold water
> pipe etc. So the MGN [HV return] gets grnded at each house as well.
> The MGN also gets grnded at each pole that has a xfmr.
> ## the xfmr voltages would be all wrong! If you are going to
> use 2 x phases..then u really need 2 x xfmr's . Unless, what ur
> proposing,
> is run one xfmr between 2 x hv phases... which is doable.
Yes, that's exactly what I mean.
Paul, W9AC
------------------------------
Message: 2
Date: Mon, 2 Aug 2010 11:34:12 -0400
From: "Bert Almemo" <balmemo@sympatico.ca>
Subject: Re: [TowerTalk] Fwd: shack wiring
To: "'Jim Thomson'" <jim.thom@telus.net>, <towertalk@contesting.com>
Message-ID: <BLU0-SMTP28EB1BB03B118596ABE3BED4AD0@phx.gbl>
Content-Type: text/plain; charset="us-ascii"
Hi guys,
I'm no expert but it seems to me that the NA electrical distribution system
is completely antiquated and needs rebuilding. Overhead wires on wooden
poles is a cheap and ugly system. It also works as unwanted antennas for us
hams.
In many countries in Europe all single family homes have 3-phase electrical
systems. Distribution lines in the urban areas are all undergorund which
make the neighborhoods look much nicer and the wires are not exposed to ice
storms, hurricanes, tornados or other common weather conditions. It costs a
fortune every year to repair overhead power lines in NA. The long term
benefits are obvious.
I wonder when we on this side of the pond realize we have to modernize our
electrical system? Just my 2 cents worth.
73 Bert, VE3OBU/SM7BUR
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Jim Thomson
Sent: Monday, August 02, 2010 10:55 AM
To: towertalk@contesting.com
Subject: [TowerTalk] Fwd: shack wiring
Date: Mon, 2 Aug 2010 08:31:22 -0400
From: "Paul Christensen" <w9ac@arrl.net>
Subject: Re: [TowerTalk] Fwd: shack wiring
> ## If the business's don't get a neutral... then how do the
> business's obtain 120 vac ??
The neutral for premise distribution is created at the utility transformer
secondary. Speaking of electrical distribution and use of neutrals, this
evolution of plant step-down architecture has always bothered me:
http://72.52.250.47/images/power-tap.gif
http://www.psc.state.fl.us/consumers/utilitypole/images/utilitypole5.jpg
In the U.S., the HV primary on a pole transformer feeding a home is tapped
between one phase of a three-phase system and a Multi-Ground Neutral (MGN).
The photo in the top link shows only one phase on the pole insulator.
Often, the other two phases are not passed in deeper residential
distribution.
### Same thing here. BUT.... we have 3 phase running down the main
drag.
1st side street gets phase A..... 2nd side street gets phase B.. etc, etc.
Then the 30,000 resisdent's total load is divide up fairly evenly between
all 3 x phases.
At each pole, a grounding conductor (shown in the second link) is run from
the MGN to earth to keep the distribution's MGN ground line at earth
potential. That's a good thing because if a ground fault occurs, it's
possible that the pole grounding conductor (runs from the top of the pole to
the ground stake) would elevate to the full 7200V delivered by the
distribution phase through the transformer primary. During a fault
condition, a person standing on the ground while touching the pole's
grounding conductor would be guaranteed electrocution.
## I don't think so. The most that could happen is the input
fuse to the xfmr would blow open. The MGN is the return leg
for the 7200/14.4 kv. Notice that the CT of the sec of the xmfr
is also bonded to this same MGN . That's done...so each home
that gets a neutral, also has the same neutral grnded to cold water
pipe etc. So the MGN [HV return] gets grnded at each house as well.
The MGN also gets grnded at each pole that has a xfmr.
## I call that an 'unbalanced HV primary. '... and a 'balanced 240 sec'..
[with a grnded CT]
Albeit more expensive for utility companies, it makes more sense to me that
for new neighborhood construction, two phases should be carried to the home
transformer's HV primary, and not between one phase and the MGN. This is
especially the case where 3-phase is available on the pole. Yet, in cases
where a residential transformer is mounted on a 3-phase pole, the utility
companies still use the MGN instead of a second phase.
## the xfmr voltages would be all wrong! If you are going to use 2 x
phases..then u really need 2 x xfmr's . Unless, what ur proposing,
is run one xfmr between 2 x hv phases... which is doable. That requires
2 hot wires to each xfmr. They don't do it that way cuz they use an UN
balanced
distribution system.
## Notice right now.. that one side of the xfmr Primary is grnded. And
that the CT
of the sec is also grnded [ both to the same MGN].
## In the UK... they use no CT on their xfmrs. [230 vac 50 hz single
phase],
BUT, one side of the sec is bonded to the MGN..and also dirt grnded. One
side of the HV primary is also grnded/bonded to the same MGN. What
they have in effect is UN balanced sec power. What they call a neutral is
just one side of the grnded 230 line. That way... you only need one spst
switch for each circuit in a house...like a light switch. [you only have
one hot leg].
The safety of the
exiting distribution is wholly dependant on the bonding quality of all
components between the MGN, the pole grounding conductor, and the earth
grounding rod.
## The MGN also extends to each home...via the neutral [ CT]..where it's
connected to a cold water pipe, etc... so the MGN gets grnded 9 x times
for each xfmr..for 9 x homes. The fault current can't flow down the pole's
safety grnd.. and zap anybody. As soon as it hit the MGN.. or anything
else..
HV fuse blows.
Tapping two phases instead of one eliminates the deadly
ground fault condition. Then again, just how many accidents or deaths
result each year from such a ground fault? In areas of *well-maintained*
plant, probably not too many.
## The reason they use the MGN set up is so if something happens
like say the xfmr develops a pri to sec short.. ur safe. with a primary
to sec short, since the CT [neutral] is bonded to the MGN.... all you end
up doing, is shorting out the primary side ! .... and the HV fuse to the
input of the xfmr blows open.
## If u did it ur proposed way..with one xfmr pri across 2 x phases...
and say you had a pri to sec short in the xfmr.... then u would end up
stuffing
7200/14.4 kv right into your living room!
## it's actually a well thought out system. Now, how 9 x homes..each with
'200A' service can all hang off the same 50 kva xfmr..is beyond me..esp at
dinner time.
The xfmr is only rated for 210 A.
Jim VE7RF
Paul, W9AC
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
------------------------------
Message: 3
Date: Mon, 2 Aug 2010 11:40:45 -0400
From: Charlie Gallo <Charlie@TheGallos.com>
Subject: Re: [TowerTalk] Fwd: shack wiring
To: TexasRF@aol.com
Cc: towertalk@contesting.com, w9ac@arrl.net
Message-ID: <12179659.20100802114045@TheGallos.com>
Content-Type: text/plain; charset=us-ascii
On 8/2/2010 TexasRF@aol.com wrote:
> Sorry Paul, I misunderstood your information. I see now that you were
> talking about neighborhood primary power distribution, not individual home
> secondary power source.
>
> I see the single phase primary distribution running for miles and miles
> out
> in the rural areas around here. As new and upgraded facilities are
> installed I see three phase distribution replacing the old plant.
I live in NYC (Queens), and I talked with ConEd about 3 Phase power (I have
a home machine shop) and was told "you want 3 Phase? No problem - You just
have to replace your panel, and pay for the lines in, and we'll give you 3
phase"
I know that a lot of the BIG houses out in the Hamptons (The Tony Beach
resort area out on Long Island) are running 3 phase as a default now
--
73 de KG2V - Charles Gallo
Quality Custom Machine-shop work for the radio amateur (sm)
------------------------------
Message: 4
Date: Mon, 2 Aug 2010 11:17:33 -0500
From: "Robert Chudek - K0RC" <k0rc@citlink.net>
Subject: Re: [TowerTalk] Rohn 45 no guys
To: <towertalk@contesting.com>
Message-ID: <1290A129986746ABA26EFE01B3892861@GX620A>
Content-Type: text/plain; charset="iso-8859-1"
Take a look at the 20 foot self-supporting figures. This must be some kind
of "magic length" as Rohn 45 with no ice will support 22 ft^2 and with 1/2"
of ice it will support 25 ft^2. The ice must be acting like a bracing
component? The 20' row appears to be the only height where the number "don't
make sense".
73 de Bob - K?RC in MN
Message: 4
Date: Mon, 2 Aug 2010 10:51:34 -0400
From: "Lee J. Imber (WW2DX)" <lee@ww2dx.com>
Subject: Re: [TowerTalk] Rohn 45 no guys
To: garyschafer@comcast.net
Cc: TowerTalk@contesting.com
Message-ID: <7C6B18C8-E654-4EAE-BC48-819D32B494EE@ww2dx.com>
Content-Type: text/plain; charset=us-ascii
Here is a Rohn chart, hope this helps.
http://www.hudsonvalleytowers.com/Docs/Self_Supporting_Tower_Chart_Rohn.pdf
73 Lee
WW2DX
On Jul 28, 2010, at 11:11 PM, Gary Schafer wrote:
> How high can rohn 45 be used with no guys if it is to be used only to
> support one end or the center of a wire dipole, say for 80 meters?
>
> How about with only top guys?
>
> 73
> Gary K4FMX
------------------------------
Message: 5
Date: Mon, 2 Aug 2010 11:19:47 -0500
From: "Robert Chudek - K0RC" <k0rc@citlink.net>
Subject: Re: [TowerTalk] Rohn 45 no guys
To: <towertalk@contesting.com>
Message-ID: <8CCFB524F14941DCBA30DC12987B5F14@GX620A>
Content-Type: text/plain; charset="iso-8859-1"
I ht the Enter key too soon... it looks like the 10 foot height shows the
same characteristic.
----- Original Message -----
From: Robert Chudek - K0RC
To: towertalk@contesting.com
Sent: Monday, August 02, 2010 11:17 AM
Subject: Re: [TowerTalk] Rohn 45 no guys
Take a look at the 20 foot self-supporting figures. This must be some kind
of "magic length" as Rohn 45 with no ice will support 22 ft^2 and with 1/2"
of ice it will support 25 ft^2. The ice must be acting like a bracing
component? The 20' row appears to be the only height where the number "don't
make sense".
73 de Bob - K?RC in MN
Message: 4
Date: Mon, 2 Aug 2010 10:51:34 -0400
From: "Lee J. Imber (WW2DX)" <lee@ww2dx.com>
Subject: Re: [TowerTalk] Rohn 45 no guys
To: garyschafer@comcast.net
Cc: TowerTalk@contesting.com
Message-ID: <7C6B18C8-E654-4EAE-BC48-819D32B494EE@ww2dx.com>
Content-Type: text/plain; charset=us-ascii
Here is a Rohn chart, hope this helps.
http://www.hudsonvalleytowers.com/Docs/Self_Supporting_Tower_Chart_Rohn.pdf
73 Lee
WW2DX
On Jul 28, 2010, at 11:11 PM, Gary Schafer wrote:
> How high can rohn 45 be used with no guys if it is to be used only to
> support one end or the center of a wire dipole, say for 80 meters?
>
> How about with only top guys?
>
> 73
> Gary K4FMX
------------------------------
Message: 6
Date: Mon, 2 Aug 2010 12:34:22 -0400
From: Ryan Jairam <rjairam@gmail.com>
Subject: [TowerTalk] Boots (for climbing)
To: "Tower and HF antenna construction topics."
<towertalk@contesting.com>
Message-ID:
<AANLkTinZ+ZD_KR0LqVZ2aDPCerdYoizLpM8R-Bj4FKks@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
What do you guys use for climbing?
I need a new pair that doesn't slip easily and is comfortable. I have
used regular work boots and motorcycle boots in the past without
issue, but I want something proper.
I have looked at lineman boots but some are uber expensive. They are
well insulated for lineman work which may explain it.
Thanks
Ryan, N2RJ
------------------------------
Message: 7
Date: Mon, 02 Aug 2010 09:44:13 -0700
From: Grant Saviers <grants2@pacbell.net>
Subject: Re: [TowerTalk] Rohn 45 no guys
To: TowerTalk@contesting.com
Message-ID: <4C56F5DD.2030906@pacbell.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Can this chart be correct? 1/2" ice antenna sq ft numbers are higher
in many cases than no ice. Weird for such a large increase in projected
area.
Grant
KZ1W
Lee J. Imber (WW2DX) wrote:
> Here is a Rohn chart, hope this helps.
>
> http://www.hudsonvalleytowers.com/Docs/Self_Supporting_Tower_Chart_Rohn.pdf
>
> 73 Lee
> WW2DX
>
> On Jul 28, 2010, at 11:11 PM, Gary Schafer wrote:
>
>
>> How high can rohn 45 be used with no guys if it is to be used only to
>> support one end or the center of a wire dipole, say for 80 meters?
>>
>>
------------------------------
Message: 8
Date: Mon, 02 Aug 2010 09:54:45 -0700
From: "Jim Brown" <jim@audiosystemsgroup.com>
Subject: [TowerTalk] Power Distribution
To: "towertalk@contesting.com" <towertalk@contesting.com>
Message-ID: <20100802165449.710A558516@gw1.nlenet.net>
Content-Type: text/plain; charset="us-ascii"
On Mon, 02 Aug 2010 11:08:25 -0400, Joe Subich, W4TV wrote:
> >> ## If the business's don't get a neutral... then how do the
> >> business's obtain 120 vac ??
>Their supply is either 120/208 (e.g. wye or star) with neutral
>being the center of the wye or they need to install their own
>480 to 240/120 transformer on premesis.
That's ordinary 3-phase power.
The High Leg Delta distribution that I described is 240V Delta. A
pure delta configuration has no neutral. The High Leg Delta is
different -- ONE side of the delta is center-tapped to provide a
neutral. A single phase user gets THAT center-tapped leg. A 3-
phase user gets all three phases (and perhaps the neutral). There
is 208V between neutral and the leg opposite the center tap.
That's the High Leg. Also called Wild Leg.
High Leg Delta is VERY widely used in cities and towns where there
are small businesses and residences on the same street, because
the same simple system can be used to feed all of them. It's also
what's I have up here in the Santa Cruz Mountains, fairly far off
the beaten track.
Think about WHY there is 3-phase power -- it's because nearly all
mains power comes from 3-phase generators, AND because big motors
want to run on 3-phase power. For other uses, single phase power
is just as efficient. AND single phase power doesn't have the
neutral harmonic current problem.
When most loads connected to the power system drew sinusoidal
current, designers could minimize neutral current by balancing
loads between the three phases. That hasn't been true for at least
40 years -- remember the Towering Inferno? There was a real one,
and the root cause was that the neutral current was nearly double
the current on a phase! That's what happens when nearly all loads
are rich in harmonics. That includes virtually anything with a
power supply, and all lighting except for old fashioned
incandescent light bulbs. Nowadays, even big motors run on pulsed
3-phase power, so the power supplies that create those pulses are
all harmonics!
73, Jim K9YC
------------------------------
Message: 9
Date: Mon, 2 Aug 2010 11:43:08 -0500
From: Michael Goins <wmgoins@gmail.com>
Subject: Re: [TowerTalk] Boots (for climbing)
To: Ryan Jairam <rjairam@gmail.com>
Cc: "Tower and HF antenna construction topics."
<towertalk@contesting.com>
Message-ID:
<AANLkTima37z9X1cC=Hju2Ts-RRNCnKTzf3q=WLX0HO=F@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
I use motorcycle boots as many have instep plates. Helps with the rungs.
Mike, k5wmg
Pipe Creek, Texas
Fast cars, slow boats, big dogs, old trucks, little radios, and
summers off to write
On Mon, Aug 2, 2010 at 11:34 AM, Ryan Jairam <rjairam@gmail.com> wrote:
> What do you guys use for climbing?
>
> I need a new pair that doesn't slip easily and is comfortable. I have
> used regular work boots and motorcycle boots in the past without
> issue, but I want something proper.
>
> I have looked at lineman boots but some are uber expensive. ?They are
> well insulated for lineman work which may explain it.
>
> Thanks
> Ryan, N2RJ
> _______________________________________________
>
>
>
> _______________________________________________
> 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
End of TowerTalk Digest, Vol 92, Issue 8
****************************************
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|
