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Model Railroader General Discussion (Model Railroader)
1

Okay, I’ve just visited digikey and fried my brain.

I need toggle switches for control panels to run tortoise motors. I believe that means I want on-on SPDT switches… But how many amps and what about all these other features??? And how much should they cost - the ones I found that I think are probably right are running $5-7 each… is that right???

Any help, sources or suggestions are MOST welcome.

2

i think

3

I found some nice toggles on Ebay. There seemed to be quite a selection out there. I ended up buying som spst center sprung toggles for about $1 a piece.

4

This will work fine:

http://www.allelectronics.com/cgi-bin/item/MTS-4/700275/SPDT_ON-ON_MINI_TOGGLE_SWITCH_.html

or these

http://www.allelectronics.com/cgi-bin/item/MTS-5/700275/SPDT_ON-OFF-ON_MINI_TOGGLE_SWITCH_.html

or these

http://www.allelectronics.com/cgi-bin/item/MTS-41/700275/LONG-HANDLE_MINI-S.P.D.T._SWITCH_.html

or these

http://www.allelectronics.com/cgi-bin/item/MTS-4PC/700275/SPDT_ON-ON_MINI_TOGGLE_SWITCH_.html

But you may want to install DPDT toggles for the extra contacts to control signaling or indicator lamps, such as

http://www.allelectronics.com/cgi-bin/item/MTS-85PC/700275/DPDT_ON-ON,_NON-THREADED_BUSHING_.html

or

http://www.allelectronics.com/cgi-bin/item/MTS-8/700275/DPDT_ON-ON_MINI_TOGGLE_SWITCH_.html

A Tortise draws a few milli-ampere (1/1000 of an amp)

There are thousands of switches that will work for this application.

5

Thanks, nfmisso. Very helpful indeed. You’re right, I should get the DPDT’s. Won’t use the second pole right away, but might as well have it.

Good pointer on ebay too, Pete. I’d forgot about that. Definitely some values there.

So far allelectronics and ebay seem roughly the same pricing, so I’ll probably go with the vendor with the phone number, return policy, etc. But… We’ll see. I don’t have to buy these immediately, so maybe I’ll wait a few days and see what turns up.

6

I use twin-coil motors, which want SPDT - momentary contact, center off. I ordered mine from http://www.demarelectronics.com and they are around a dollar each, depending on quantity ordered. They’ve got all the other flavors of switches too.

7

For my tortises I went to an electronic surplus store. I got two power supplies and following the directions used SPST that I got for a buck. They work just great. Here abouts there is a place called Axman Surplus. Most cities have such. Great prices if they happen to have what you want.

8

Nigel or anyone, would a 6 amp switch be too much?

9

I use the big ones with the 250 volt rating…as long as they are rated for higher than what ever your power pack puts out they will work… here’s a place i use www.partsexpress.com they are fairly reasonable on their prices…chuck

10

Thanks, all. I found some DPDT 6amp@125V ones on E-bay for $0.65 each. Think I’ll go with those.

11

K Chronister

Unless you want a physically big toggle switch, a 1/2 (500 ma) amp rating is more than plenty for a Tortise. The higher ratings do no harm, but they do make the toggle switch physically bigger and sometimes more expensive.

The only caveat to using ratings in line with normal current draws is adequate short circuit protection. If your power supply has a circuit breaker that doesn’t trip until 5 amps is being drawn, and your wiring, switches, contacts, etc are rated at 1 amp, then when an almost short circuit occurs that doesn’t trip the breaker, your wiring is over-loaded and may melt/weld/get very hot. This is a big, much ignored problem in 3 rail O, and will become much more of a problem in the smaller gauges with large DCC power supplies.

Joe Fugate’s DCC light bulb current-limiting system is great - but requires that all your wiring be capable of sustaining a 2 amp current continuously. Please keep that in mind when you size your feeders, since most shorts in model railroading occur at the track or at end device (such as switch machines).

In kchronister’s case, the toggle switch should be rated at the capacity of his Tortoise power supply, unless he has a circuit breaker, current limiter, or fuse which will limit the circuit to less.

Hope this helps.

yours in wiring
Fred Wright