Using the Scalefour Society Lever Frame with Tortoise Motors

Discussions of the prototypes and how to model them. Show us how you do it.
mikeknowles
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Using the Scalefour Society Lever Frame with Tortoise Motors

Postby mikeknowles » Thu May 09, 2013 12:37 pm

At last months Scalefour North I purchased the 5 lever frame kit from the stores on the basis that it could be used for operating the turnouts either mechanically or electrically. My intention is to use Tortoise motors (already purchased and installed). On reading the kit instructions reference is made to using MSR500 Mini Microswitches from Squires which are described in their catalogue as single pole changeover switches, however the instructions with the Tortoise motors refers to using either a DPDT switch or 2nr SPDT switches.
Could someone please explain (in basic terms - I'm not into this elastictrickery) whether it is possible to use this lever frame kit with the aforementioned microswitches, if so how do I make the electrical connections; do I need to change the type of switch, if so to what; or have I been mis-sold (joking) this item.

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Russ Elliott
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Re: Using the Scalefour Society Lever Frame with Tortoise Mo

Postby Russ Elliott » Thu May 09, 2013 3:18 pm

I'm not familiar with the lever frame instructions (which I thought might be accessible via the Stores page, but it wasn't there), but I assume the single pole changeover microswitch being referred to is for the purpose of switching the vee polarity.

To operate a Tortoise point motor, a DPDT switch is required, unless using a split-potential supply.

DPDT microswitches are not available in the size you want, as far as I am aware. Your best bet might be a DPDT slide switch, something like this, whose switch travel is 3.2mm, so you would need to gang the switch to the frame lever in some way. Not a particularly elegant solution, and I'm sure others will have discovered better implementations.

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Tim V
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Re: Using the Scalefour Society Lever Frame with Tortoise Mo

Postby Tim V » Thu May 09, 2013 3:38 pm

The subject of split potential supply for Tortoises etc was covered very recently, though I can't remember in what thread. Far better to use the switch the frame was designed for rather than modify for a different switch.

I covered building a split potential power supply for point motors in an old Snooze, should be in the index.
Tim V

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grovenor-2685
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Re: Using the Scalefour Society Lever Frame with Tortoise Mo

Postby grovenor-2685 » Thu May 09, 2013 3:40 pm

To operate a Tortoise point motor, a DPDT switch is required, unless using a split-potential supply

True, but a split potential supply is simple to produce with two diodes on a transformer, the circuit is shown on the tortoise instructions and is the best way to wire them up. The frog can then be switched with the tortoise contacts so the SPDT microswitch is adequate.
If you are not using a transformer supply the split potential can be obtained from two cheap plug in PSUs.
If you can specify what power supply you have we can get into more detail.
Keith

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grovenor-2685
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Re: Using the Scalefour Society Lever Frame with Tortoise Mo

Postby grovenor-2685 » Thu May 09, 2013 3:48 pm

The subject of split potential supply for Tortoises etc was covered very recently, though I can't remember in what thread.

Try here
http://www.scalefour.org/forum/viewtopic.php?f=26&t=1094&p=7379&hilit=tortoise#p7370
Keith

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Tim V
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Re: Using the Scalefour Society Lever Frame with Tortoise Mo

Postby Tim V » Thu May 09, 2013 3:57 pm

Good find Keith, but it was a bit more recent than three years ago!

Try this one!

viewtopic.php?f=5&t=694&p=23093&hilit=split#p23093
Tim V

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Mark Tatlow
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Re: Using the Scalefour Society Lever Frame with Tortoise Mo

Postby Mark Tatlow » Thu May 09, 2013 4:09 pm

I have dealt with this by using DPDT toggle switches. If you go for the sliding versions, you can drill a hole through the toggle and then pass a bar through it. The bar is an extension of the cradle that is provided in the kit for manual operation of bars.

There are a number of pictures of this on page 4 of my A Highland Miscellany thread - viewtopic.php?f=91&t=1345&start=75

Once set up, these have been very reliable. The only problem I had was with the cradle detaching from the bar - whcih is why I use a continuous bar bent around the cradle.
Mark Tatlow

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dcockling
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Re: Using the Scalefour Society Lever Frame with Tortoise Mo

Postby dcockling » Thu May 09, 2013 9:07 pm

Russ Elliott wrote:I'm not familiar with the lever frame instructions (which I thought might be accessible via the Stores page, but it wasn't there).


In the 'Downloads' section of the website Russ:

http://www.scalefour.org/downloads/downloads.html

All the Best
Danny

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Russ Elliott
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Re: Using the Scalefour Society Lever Frame with Tortoise Mo

Postby Russ Elliott » Thu May 09, 2013 10:16 pm

Whoops! Er, thanks Danny! (The Stores list is currently inconsistent though in its references to the download page, which is why I drew an initial blank.)

Terry Bendall
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Re: Using the Scalefour Society Lever Frame with Tortoise Mo

Postby Terry Bendall » Fri May 10, 2013 6:02 am

A suitable microswitch is also available from Maplins although I don't know the reference number. The switches used on the lever frame that is usually found on the Societry stand came from that source.

grovenor-2685 wrote:True, but a split potential supply is simple to produce with two diodes on a transformer, the circuit is shown on the tortoise instructions and is the best way to wire them up. The frog can then be switched with the tortoise contacts so the SPDT microswitch is adequate.


I have used this method on three different layouts and it is fine.

Terry Bendall

Alan Turner
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Re: Using the Scalefour Society Lever Frame with Tortoise Mo

Postby Alan Turner » Fri May 10, 2013 7:22 am

The micro switches are standard V4 micro switches. The one you want is a roller lever and with solder terminals (rather than PCB terminals).

They are available from all the usual suspects: Rapid, Maplin, Farnell, RS Components etc.

As they are SPDT you need to use the method of control shown with AC supply and diodes.

By the way you need approx. twice the AC voltage of the DC voltage you need.

Alan
Tortoise.jpg
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Last edited by Alan Turner on Fri May 10, 2013 7:27 pm, edited 2 times in total.

mikeknowles
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Re: Using the Scalefour Society Lever Frame with Tortoise Mo

Postby mikeknowles » Fri May 10, 2013 1:18 pm

Many thanks for all your replies. On the basis that the micro switches referred to in the instructions are in fact SPDT (something I wasn't sure about) I'll have a go with them using the split supply. If this doesn't work I'll try Mark's idea with the DPDT slide switches.
Again thanks for all your help.

allanferguson
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Re: Using the Scalefour Society Lever Frame with Tortoise Mo

Postby allanferguson » Fri May 10, 2013 1:44 pm

When I illustrated the use of the split potential power supply as used on Bonnybridge Central, I made the point that only SPDT switches were required. I also commented that we in fact used DPDT switches, so that the crossing polarity was switched from the panel. This required more wire, but was much more reliable -- we have had enough problems with the switches on the Tortoises on Burntisland to justify this view. And we're all getting too old to crawl under baseboards to fix things at an exhibition! Ever since my first experience of H & M and Peco points motors I have had a profound distrust of built in switches for crossing polarity.

Allan F

mikeknowles
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Re: Using the Scalefour Society Lever Frame with Tortoise Mo

Postby mikeknowles » Fri May 10, 2013 1:51 pm

Interesting comment Allan with regard to using Tortoises for polarity switching. The reason I went with them was because of my perceived view of their reliability! Time will tell if I was right!

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Russ Elliott
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Re: Using the Scalefour Society Lever Frame with Tortoise Mo

Postby Russ Elliott » Fri May 10, 2013 1:58 pm

I think the Tortoise internal switches were upgraded at some stage.

Alan Turner
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Re: Using the Scalefour Society Lever Frame with Tortoise Mo

Postby Alan Turner » Fri May 10, 2013 2:21 pm

If you get some micro-minature micro-switches these can be attached to the Tortoise casing (using two screws) and used to switch the crossing polarity.

regards

Alan

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Russ Elliott
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Re: Using the Scalefour Society Lever Frame with Tortoise Mo

Postby Russ Elliott » Fri May 10, 2013 3:19 pm

So, the http://www.scalefour.org/resources/tortoise-wiring.html page tells only half the story?

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grovenor-2685
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Re: Using the Scalefour Society Lever Frame with Tortoise Mo

Postby grovenor-2685 » Fri May 10, 2013 7:09 pm

Well under half I'd say, just gives the most basic option of several, even the instructions with the tortoise give a lot more.
Keith


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