The internal contacts on the Tortoise work - although sometimes they do not break before the turnout points are actually thrown and a momentary short will result. This can happen with the the 3PDT switdh as well. It gets thown, and the Switch Tender has not thrown the points yet. If you have insulated frogs(DCC Friendly), this is not a problem.
On to the rest of the Switch Tender/Tortoise issues:
The Switch Tender draws about 60ma(even with the current limiting resistor). I have never seen a Tortoise draw more that 18ma. This means that you can wire your bi-color LED in series with the Tortoise(pin #1 or #8) and just use a cheap DTDT toggle to control it - Very simple wiring. This is because you do not want to run more than about 20ma through most bi-color LED's(more than that may result in a burned out LED). I bought a Switch Tender when Micro-Mark started selling them. They are easy to install, but until I read the instructions, I was unaware of the high current draw. I think they mention the current draw in their web catalog now.
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
Yes and mostly no.
Yes, the contacts on your electrical switch are probably slightly more reliable than the contacts on the Tortoise for switching frog polarity. I've used a toggle switch thrown separately along with moving the points by hand until I got around to installing a throw for my hand laid turnouts. The toggle simply controlled the frog polarity in the interim; later on it would control both frog polarity and switch machine.
No, the proposed method will cause short circuits if your points are electrically linked to the frog. In this case, the toggle (or slide) switch is thrown before the switch machine moves the points. This means the closed point is of opposite polarity to the stock rail it is touching - forming a short circuit - from the moment when the toggle is thrown until the switch machine moves the point away from the rail. Of course, if your frog is electrically separate from the points, and the points are hard wired electrically to the adjacent stock rails at all times, then either method of switching frog polarity works well. The latter, in my estimation is a best turnout wiring practice, regardless of whether you use DC or DCC. All my hand laid turnouts use this wiring scheme.
Bottom line - the way your turnouts are wired determines if the Switch Tender scheme will work well. Also, be advised 3PDT toggles or slides are harder to find, and cost more, than a DPDT.
hope this makes sense and answers the question
Fred W
The Micro Mark Switch Tender uses a three pole double throw to activate the machine and to control the polarity of the frog. Does this method of controlling the polarity work as well as the internal contacts of the Tortoise?