A Crossing Gate No. 252 Question

[KRM]

I have an outer loop run by a ZW and an inner loop run by a CW-80. I am running a Crossing Gate No. 252 off an isolated track section and CTC LockOn on the inner loop and want to also run the same gate off the outer loop with another section of isolated track. What will happen when both trains are passing at the same time with power coming from both transformers?

 Can this be done?  If so how?

Thanks.

[rtraincollector]

Kevin I'm not sure it can be done with out over loading the 252 sending you a email 

[lionelsoni]

Yes, it can be done.  But you should power the crossing gate from a single source, which, since you would want the crossing gate to operate even if only one track is powered up, should be on all the time, rather than using either loop's track voltage.  This could be a third transformer, or it could be simply one of the accessory voltage sources available from either the ZW or the CW-80.

In addition, you will have to connect the outside rails of the two loops together.  These should be connected to the U terminals of both transformers.  You can do this at the track or at the transformer terminals.  If you have any connecting track, like a crossover, between the two loops, you have probably already done this.

Then connect the control rails on the two tracks together and to the crossing gate.

Do you have the revised version of the CW-80, with a "G" in the part number?

[KRM]

Yes I have the newer CW-80 with the G. I have accessory power from the CW-80 on this side of the layout running lights and a control tower I could tap. No crossover.

Would be nice to see it drawn up.

Thanks,

[lionelsoni]

I'm sorry that I don't have a way to make or post a drawing, Kev.  Just make these connections:

inner-loop outside rails--CW-80-U--ZW-U--outer-loop outside rails

inner-loop center rail--CW-80-A

outer-loop center rail--ZW-A(or D)

inner-loop control rail(s)--outer-loop control rail(s)--252-A

CW-80-B--252-B

252-A and 252-B are the two crossing-gate terminals, which I think are unmarked.

[KRM]

Thanks Bob, I will give it a try. But I have to make a three section isolated track first for the outside loop.

 

[sir james I]

Seems to me connecting both inslated tracks to the ground post and seperate power, not from the track, to the other post would do the job.

[Michael6268]

I don't know why this is being made to be so difficult. Take the hot lead from your grounded power supply and attach it to one post at the crossing gate. Run two leads off of the other post to each insulated rail on your insulated track sections. And it will work off of both tracks. You don't have to worry about too much voltage being drawn because you're only drawing the voltage from the transformer. If both trains are on both insulated tracks you can't draw more voltage than what the transformer is set to. All it's doing is completing a ground.

[sir james I]

I'm pretty sure that's what I said. Condensed version.

[lionelsoni]

Is there some problem with ensuring that both transformer commons are connected to the outside rails and to each other?  He might not have done those things with two isolated loops.

[KRM]

Thanks guys,

Been looking at things. The CW-80 and the ZW both use U post to the outside rails. But I found using my meter I get a reading that shows voltage crossing from outside rail to inside rails. Can that be caused by these suppressors things?

 I set the meter to 200 and it does not show a full reading like I get from U to outside rails?

 Since these things do connect the outside and inside that is why I was wondering?

 I built a four section insulator track section to place on the outer loop like I have on the inner loop and then I will wire the outside insulated sections to one post on the gate and accessory power from the CW to the other, That should do it ,,,Right?

[KRM]

Did what I said below and tied the outer rails from both loops to each other and,,,,Well it works just great off both loops. I was scared to mix grounds from the two transformers to each other but I guess it don't matter.

 Thanks for all the help Guys!!! 

[lionelsoni]

A TVS does provide a path for current between the rails, but only when the instantaneous voltage exceeds the threshold that the device is designed for.  So the device has to be selected for voltage greater than the peak voltage that the transformer normally supplies.  This is about 40 percent higher than the RMS voltage that the transformer is rated for.  I usually recommend a 36-volt device.

The pass element of your CW-80, that is, the thing (a triac) that turns on and off 120 times a second to regulate the voltage has a capacitor in parallel with it that lets a little current leak past it all the time.  If the only load on the track is a very high impedance device like a voltmeter, that trickle will be enough for you to see some voltage.  It can also cause trouble with electronic e-units, which refuse to switch out of neutral, because it looks to them like you haven't turned the voltage off.  (The cure for this is to put a small load, like a single lamp, across the circuit to get that voltage close enough to zero.)

Is your ZW a real postwar ZW, or the modern contraption?

[KRM]

 Bob when I check not for voltage but use the ohm meter to see if there is a short / continuity between the outside and inside rails is when I see it. I only have the suppressors on the side I run the post war ZW on and I see no sign of crossing on the CW loop when I go between the inside and outside rail but on the ZW side with the suppressors it tries to tell me they are connected. Why I thought it had to do with the TVS providing a path for current between the rails.

[lionelsoni]

There's something drawing current on that outside loop.  I see that you soldered the TVSs to lockons.  Can you easily take the lockons off the track and then measure the resistance between rails?  It looks like you could also disconnect the supply wires from the lockons and get a resistance measurement of each individual TVS.  At this point, it seems like there is a mystery load somewhere or that one of the TVSs has failed and is conducting at a very low voltage--the voltage supplied by the ohmmeter.

[KRM]

Bob, the outside loop is over 60' long around and has about 10 Lockons. Some I soldered an some I just did like this.

And there is one for every turn / pull off ( three of them ) and yard parking leg  ( six of them ). They are all over the place. I counted 21 lockons in all running off the ZW for the two loops it runs and the MOW bump stop run. The CW-80 just runs the kids side and accessories. All of the other table accessories and stuff runs off a 1044 transformer.

Could it be because there are so many TVSs?

it is a nut house of wires.

[KRM]

Bob,, I got it, everything ran perfect,,,,,,,,,,,knocking my brain out and looking at the train I had on the track and then it hit me like a ton of bricks. There sat an Extension Searchlight Car No. 3650. Remove the car no continuity. Perfect for the main loop.

 Inner logging loop, the lighted bumper. The MOW bump stop run,, two lighted bumpers.

 The light filaments were carrying the current from inside to outside rails!!!!!!!!!! 

Man that had me going. 

Thanks again, I need a break.

[lionelsoni]

Congratulations!

[KRM]

I am a hydraulics guy, but electricity and hydraulics are a lot alike but with hydraulics if you have a leak something moves. This problem I had yesterday with the layout had me for awhile.   The new cars are a impossibility to work on.

[traindaddy1]

I have nothing to add.

Just want to say thanks to Bob and all for the education.

I learn something new every day about this hobby.

[lionelsoni]

You're welcome!