Crossover "Short"


Ted Hutchinson
 

Stumped by wiring issue: I've been using NCE Power cab with the NCE SB5 for years with no problems on my layout. Recently I installed nearly 30 Tortoise machines with separate DCC power. Six of the machines control three crossovers (2/crossover). All of a sudden when I activate one of the mainline crossovers to divert to the other route I get a momentary short - as one might get using a reversing loop. The locomotive(s) stop and then restart in second or two. It does not happen when "switching" back to the "through" route. It's diving me nuts! Help? Thoughts?


Don Vollrath
 

Ted, are you using any of the DPDT switches inside the tortoise units to selectively power the frog? If so, verify that the mechanical alignment is such that the internal contacts “throw” while the rail points are open between final positions. Both directions of movement.


DonV


Allan AE2V
 

Crossovers on model railroads are frequently connecting tracks in a folded dog bone track plan.  Is that the case in your railroad?  The polarity is reversed in going across the crossover.  For more information on reversing through crossovers, go to my website at:

https://wiringfordcc.com/track_2.htm#a43

Allan Gartner
Wiring fro DCC


thomasmclae
 

Are you powering the frogs through the tortoise relays? We have found that some tortoises do not have a dead gap when the relay throws, so the frog shorts in the center of the throw. We had to use both relays to get proper frog powering.
also, You might have the relay changing the power before the rails stop making contact with the outside rail. As in, tortoise starts to move, relay makes for new route, then rails in the turnout move.
Timing can bite you! 

Thomas
DeSoto, TX


Blair
 

Somewhere, a long time ago, I read of a person opening up his Tortoises and increasing the gap on the circuit board by filing away some of the copper pad.  While this would work, it does void your warranty, so it's up to the OP whether that's acceptable.  I don't know what I'd do with a warranty on a $20 item anyways, it would cost me most of that in shipping just to send a defective product back.


On 2021-12-18 11:05, thomasmclae via groups.io wrote:
Are you powering the frogs through the tortoise relays? We have found that some tortoises do not have a dead gap when the relay throws, so the frog shorts in the center of the throw. We had to use both relays to get proper frog powering.
also, You might have the relay changing the power before the rails stop making contact with the outside rail. As in, tortoise starts to move, relay makes for new route, then rails in the turnout move.
Timing can bite you! 

Thomas
DeSoto, TX