Towertalk
[Top] [All Lists]

Re: [TowerTalk] rotating tower or stack : rpm

To: 'Al Kozakiewicz' <akozak@hourglass.com>
Subject: Re: [TowerTalk] rotating tower or stack : rpm
From: Richard Riley <Richard.Riley@tango.hr>
Date: Wed, 4 Oct 2017 17:32:28 +0000
List-post: <mailto:towertalk@contesting.com>
Hi Al,

and thanks Charles, John and John (2!) for your swift input!  I had queried 
Green Heron initially but went on to purchase (the locally available) 4O3A 
RG...only to learn (after their online doc was subsequently updated) that their 
box only supports start/stop on lower voltage applications :-(.  So now I have 
the versatile 4O3A box, with all its bells and whistles (from a networking 
perspective)..but am missing the control signals to push in to a soft starter 
anyway.  Hence my switch of focus to a VFD solution, to simply slow things down 
if necessary.

All that said I am more concerned about soft stop than soft start.
I read a horror story about a tower that twisted itself around its guys in the 
Czech Rep. a year or so back. The rotor stopped, but the inertia (from the long 
boomed beams) just kept the tower turning.

All will be revealed shortly when the tower goes up, the motor is fully loaded 
and trials started.

Stay tuned :-).

rgds Richard 



-----Original Message-----
From: Al Kozakiewicz [mailto:akozak@hourglass.com] 
Sent: Wednesday, October 4, 2017 7:16 PM
To: Richard Riley <Richard.Riley@tango.hr>; 'towertalk@contesting.com' 
<towertalk@contesting.com>
Subject: Re: rotating tower or stack : rpm

It wasn't clear why you were concerned.

Soft starts are common in industrial applications, though I can't recall ever 
seeing one used where the output of the reduction drive was 1 RPM!

That motor spec sheet shows an integral  mechanical softstart (i.e., a 
flywheel) as an option.  Otherwise the standard industrial devices are 
candidates. Honestly, soft starts on big motors are more used to limit inrush 
current than for any mechanical protection. They can be as expensive as a VFD 
or as simple as an inductor.

Al
AB2ZY


________________________________________
From: TowerTalk <towertalk-bounces@contesting.com> on behalf of Richard Riley 
<Richard.Riley@tango.hr>
Sent: Wednesday, October 4, 2017 12:54 PM
To: 'towertalk@contesting.com'
Subject: [TowerTalk] rotating tower or stack : rpm

Hi guys,

my previous post (reference soft-start and frequency regulation of motor on a 
rotating tower) drew no responses :( :(...
...so I'll try it from another angle.  I'm about to erect 102ft of 20inch- to- 
a-side, triangular rotating tower (loaded with 12-15m boomed monobanders from 
40-10) on a 3 phase motor, with a projected speed of 1rpm..and am concerned 
about the potential for start/stop stress.

You have a large stack or a rotating tower.

How fast does it rotate?

Have you employed a soft-start-stop system to prevent mechanical shock?

If so, what did you choose?

Your input appreciated!

73 9a1tt

Richard Riley

mob: +385(0)993 994 995
direct: +385(0)1 5494 303


[http://www.tango.hr/images/tango.png]<http://www.tango.hr>
tango komunikacije d.o.o.
Strojarska cesta 22
10000 - Zagreb - Croatia
office: +385(0)1 5494 301
fax: +385(0)1 5494 315
EU VAT#: HR73112507864

[http://www.tango.hr/images/eu.png] [http://www.tango.hr/images/fondovi.png]  
[http://www.tango.hr/images/competitivecroatia.png]
Ulaganje u budu?nost
Europska unija
Investing in your future
European union

Projekt Podizanje konkurentnosti putem uvo&dstrok;enja inovativnih IKT rje?enja 
u poslovne procese tvrtke tango komunikacije sufinanciran je uz pomo&cacute; 
Europske unije iz Europskog fonda za regionalni razvoj.
A recent project Improving tango's competitiveness by introducing innovative 
ICT solutions in our business processes, was co-financed by the European Union 
from the regional development fund.
_______________________________________________



_______________________________________________
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

<Prev in Thread] Current Thread [Next in Thread>