Thanks for all the inputs/suggestions. They are much appreciated.
I already have emailed Karl about motorizing the WT-51, but have not yet heard
back from him.
I am still trying to develop a concept for a positive pulldown mechanism with
electric winch. However, I am also planning to add some extra safety features
(based on everyone's safety concerns expressed), such as power interlock and
cameras and lights to ensure that I can see the sections as they come down
Once I develop a concept and validate that it works, I will share it on
I am also still looking for a good schematic for a remote control unit, with
relays, time delays, etc. which can be activated remotely with a couple control
wires. If anyone has a good schematic (with parts list), it would save me some
When I bought my W-51 in 1992 from TriEX I asked their
then sales mgr. Mike Feryan, who I ran into at Dayton
this year, about motorizing it. He said that tower
was never designed to be motorized. If I find his
business card, he works for another company now since
TriEx itself went out of business, I'll give you his
e-mail address. Or better yet, if you'll e-mail Karl
Tashjian at Tashjian Towers (contact e-mail should be
on their website) he can tell you exactly. Karl was
the Califnrnia engineer who was one of the designers
of the W-51 and his "wet stamp" is on the engineer
drawings I received when I bought by W51 in 1992.
Karl now ha "sort of" revived the old TriEx line of
--- NPAlex@aol.com wrote:
> 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" <email@example.com>
> Subject: [TowerTalk] Tri-Ex WT-51 Electric Winch
> with Pulldown
> Mechanism and RMC-1000
> To: <firstname.lastname@example.org>
> Message-ID: <000001c8e09e$e2570ef0$ac00a8c0@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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