[TowerTalk] WT-51 remote/winch

NPAlex at aol.com NPAlex at aol.com
Thu Jul 10 07:07:09 EDT 2008

The cautions that you have received are very real potential problems when  
motorizing a crank-up tower.  Although I have not worked with the Tri-Ex WT  
series, I have motorized, and remote controlled several Tri-EX LM-470 towers,  
and currently have a US Tower HD-589 that has the remote feature.
The RMC-1000 controller is a US Tower item, and is nothing more than a  
grouping of switches and indicator lights for power on, Remote/Local, Tower UP  and 
Tower Down.  It does not supply power to operate the winch motor, but  does 
control a remote relay that does activate the remote control box at the  tower. 
 That box contains relays for UP and DWN (reverses the motor  rotation), two 
time delay relays to prevent switching direction too quickly (if  you don't 
delay, the motor keeps going in the same direction). and also  interfaces with 
UP and DWN limit switches.
One key issue is the winch type and drum size.  The type should be  worm gear 
driven, a ratio of about 40:1, The drum size in the 3 to 4 inch  diameter, 
and the length must be capable of hold all the cable in ONE single  layer.  You 
can not jumble wind cable when using a positive pull down  cable.  You do need 
a long eyebolt with a very heavy coil spring of at  least 8 to 10 inches long 
(a 51 foot tower may get away with less).  This  spring maintains positive 
tension on the down cable, and compensates for the  normal stretch or give in 
the cables.
The amount of UP cable that spool onto the drum is a function of the lift  
cable design - Late model LM-470 towers this cable went to the top of the base  
section, down to the bottom of the first moveable section, and then back to 
the  top of the base section.  This is a two to one mechanical advantage, and  
the amount of cable winding onto the drum is double the length that the first  
section moves.

From: "Bill Kerns" <bill at billkerns.com>
Subject: [TowerTalk]  Tri-Ex WT-51 Electric Winch with Pulldown
Mechanism  and    RMC-1000
To:  <towertalk at contesting.com>
Message-ID:  <000001c8e09e$e2570ef0$ac00a8c0 at Bill>
Content-Type:  text/plain;    charset="us-ascii"

I recently purchased a  used Tri-Ex WT-51 tower with manual winch.

I want to install an electric  winch on the tower to allow me to raise and
lower it.

Since the tower  will be located remotely from the house (about 200-300
feet), I'd also like  to figure out a way to raise and lower it remotely.

I have also found  a used RMC-1000 remote controller and am considering using
it in conjunction  with an electric winch.

However, I have heard that there is a pulldown  safety issue involved with
this tower.  So I need to have a way to pull  down the top antenna tower
sections, as the tower is being lowered, to ensure  that it does not get hung
up on the way down.  My understanding is that  the WT-51 top sections may
sometimes bind on the way down, so having this  second cable pulldown
mechanism will prevent that.

I am considering a  single winch with 2 cables wound in opposite directions,
so that as one cable  winds up, the other cable unwinds.  Then I need to add
some pulleys to  route the second cable through the middle of tower up to the
top section, so  that when the tower is lowered, this cable will pull down
the top section as  the other cable releases.  However, someone said that
this might be  problematic, since the 2 different cables may not wind/unwind
at the same  rate, so I also will need a spring mechanism to take up the
slack as the  cable winds/unwinds.

I would appreciate whatever advice anyone could  provide to help with this
installation- such as recommended electric winch  model part numbers,
suggested ideas for using RMC-1000 or similar remote  system, pulley layout,
etc.  I also wonder what the maximum distance is  that the RMC-1000 will
operate remotely, since there will be 200-300 foot  separation between the
house and antenna tower.

I am also looking for  a softcopy of the RMC-1000 schematic and manual, if
anyone has  one.


Bill, N6DAG

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