Common ground question

I'd run them all back to the terminal strip that feeds the track.

Be sure to phase all transformers.

Thanks for the suggestions! Unfortunately, I forgot to mention one important detail. The crossing gates are on my double track mainline with each line on a separate TIU channel. If I use a common ground, the two channels will no longer be isolated. I have some IR sensors from Aztrac that I may try. For the signal bridge, I will use a separate auxiliary power supply for each side and use the common ground back at the terminal strip (after I phase all power supplies!). Seems there are a lot of folks who don't like IR sensors, but they sure seem convenient. I am planning on trying some of the Z-stuff crossing signals and signal bridges if they ever get them back in stock.

Shack,

 

This year on my Christmas layout, I have 6 crossing gates and two gateman  shanties, all driven by insulated rail Realtrax. Two separate main loops fed by 3 TIU channels.

 

The accessories all run on separate transformers from the track power. The gnds of all of it tie into each other. I have them after the TIU outputs, but that is just because I use barrel jacks to get the 3 Z1K bricks into the unit, and I can use a lockon and drop a wire to get a quick gnd by the accessory.

 

I am sure PW or other transformers could have the gnds tied before the TIU, or after, I do not see where it would make a difference.

 

All works well for me. I see no problem with yours working either if all is phased and gnded correctly.

 

Greg

Hey Greg. Thanks for the reply! I will phase all power supplies and tie in the grounds to my terminal strips which are centrally located on my layout and see what happens. I do quite a bit of electrical work when I do house remodeling, yet I can't quite wrap my had around this basic issue! I'll be sure and post my results and I appreciate everybody taking the time to help me out. My five year old will be thrilled (as will his Dad!).

Shackdaddy, there is no point in, or need to, isolate grounds between channels.  In fact, they should be tied together.  Note that in Rev G TIU's, they were all tied together internally.  ISolation is impossible, given that trains crossing from one channel to another will make a connection, and it is best to have a solid connection via wire that a spotty and intermittent connection through wheels.

Black and Red are power to the crossing gate. Note the rail connections  Black attached to the outside rail.  Accessory common and Rail common one and the same.


I combine Accessory and Track common with these buss bars.


The other three wires Blue, Yellow, and White are the trip circuit for up and down.
Touch the Blue and  Yellow together and the gate goes down.


Touch the Blue and White together and the gate goes up.


I use a relay board and isolated Rail section to trip the crossing gates.
Blue, yellow, and white correspond to the crossing gate  trip circuit wires shown above.  The third wire down from the top (Green) is the isolated rail input to the board.  For this to operate the rail and accessory commons have to be one and the same.   Top two wires are Relay board power Black and Red.

Mike, you introduced a variable I failed to consider...the use of the new gates that need a relay circuit to put them down, then up.

 

My solution was for the old style "gravity takes me up, solenoid holds me down" type gates. Hope I did not confuse him.

 

Thanks for posting such a concise explanation for him if he is using that style.

 

Greg

A big thanks to everyone who offered advice on my situation. I phased all the transformers and connected the grounds at the track buss strip. Gates and signal bridge are working perfect. One FYI; if you are using a light bulb to phase transformers, know that the bulb does light up when things are phased correctly. I built an adapter plug to reverse polarity and plugged all of my power bricks/transformers in both ways just to be sure. The light bulb was MUCH brighter when things were out of phase and it allowed me to be sure I hade things phased correctly. Now, onto the scenery......

Your outer rails already are a common ground,you should be able to hook them together without issue. The just use a relay to activate any accessory, described here

 

http://www.jcstudiosinc.com/Bl...=410&categoryId=

 

Dale H