Which DPDT is needed ?

[LonePine]

Digi-Key and Mouser are confusing for a novice in choosing a toggle switch for my Tortoise Switches. Could someone tell me the specs I'm going to need.

[Texas Zepher]

LonePine

Digi-Key and Mouser are confusing for a novice in choosing a toggle switch for my Tortoise Switches. Could someone tell me the specs I'm going to need.

Any DPDT switch will work.  Tortoise switch motors draw so little current the lightest of DPDT will do. Choose which ones you like.  I would look for ones that have a definite action to them - not mushy or questionable on what position they are in.

 

[tomikawaTT]

DPDT?  What are you using the extra set of contacts for?

IIRC, Tortoise machines only need a single wire to carry either positive or negative from panel control to machine.  If you use a diode divider at the toggle switch the hot side of a twelve volt AC source connects to the center post, two diodes (one reversed from the other) connect to the outer posts and are connected to a single wire at the opposite ends.  That control wire runs to one motor input on the Tortoise, the other is connected to the cold side of the AC source to complete the circuit.  That cold-side connection is a layout-wide bus, not an individual wire for each machine.

Advantages?  A lot less wiring running from panel to switch machines, and regular on-on SPDT toggle switches are a lot less expensive than equivalent DPDTs.  The low-amperage diodes can be had for a nickle or so apiece if bought in bulk.

I use a variant of this curcuit to power twin coil machines - takes a pair of three amp diodes at each end of that single wire.  Considering the price of wire and the size of my layout, 36 cents worth of diodes per machine usually saves me at least twice that in money, plus the priceless reduction in installation and troubleshooting time.

Chuck (Modeling Central Japan in September, 1964)

[LonePine]

Basically I'm following the instructional sheet that came with the Tortoise. Your suggestion is a method I had not come across before in my learning curve. This is my first layout which has 20 swtches and 150 ft.of track. Is there any other special requirement on the diode ? Thanks for your assistance.

[JoeinPA]

 Since the current draw is so small most low amperage diodes will work.  The 1N4000 series are common and should be available at Radio Shack or others.

Joe

[CSX Robert]

Texas Zepher

Any DPDT switch will work.

Except that you do not want to use momentary contact switches(they often have (ON)-OFF-(ON) in their descriptions, if it says ON-OFF-ON - without the parenthesis, then it is fine). You can use momentary contact switches, but then you have to hold the switch down until the turnout completes it's throw.

[Allegheny2-6-6-6]

 Either one of these will work and the price is right.The first link is the proper wiring for the switch in case you didn't have it.

http://cs.trains.com/trccs/themes/trc/common/viewimage.aspx?img=http://i66.photobucket.com/albums/h259/slow_rr/SLOW_RR/WiringToggle.jpg&w=267&h=396

 

 http://www.goldmine-elec-products.com/prodinfo.asp?number=G15190

 

 http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=21952

[rrinker]

CSX Robert

Texas Zepher

Any DPDT switch will work.

Except that you do not want to use momentary contact switches(they often have (ON)-OFF-(ON) in their descriptions, if it says ON-OFF-ON - without the parenthesis, then it is fine). You can use momentary contact switches, but then you have to hold the switch down until the turnout completes it's throw.

 

 Actually, for Tortoises you want the ones that say On-On (no parentheses and no Off in the middle). Tortoises like the power to be applied all the time. On-Off-On is a designation for a center off switch. So, if you go for straight DC power and a DPDT, or if you use AC and a pair of cheap diodes at each toggle and use SPDT, look for ones designated ON-ON.

                                                   --Randy

 

[LonePine]

Thanks to all for the information. Great sources on the forum. LonePine