Lionel 153IR Accessory Controller with Postwar KW Transformer

The issue with powering up accessories is that one connection is to the center rail power and the other to the side rail (U terminal)  .  If you switch the expected connections to a switching element that controls center rail power ( 153IR) you end up putting one side of the AC power into both power terminals of the accessory being controlled and this won't work.  Here's a simple test to tell what terminals are which on the KW transformer.  Place a volt meter (or one bulb lead) on the U terminal. Touch the other side of the voltmeter (or bulb lead) to the unknown terminal. If they read a voltage (or the bulb lights) then they are the hot side if not they connect to the U or ground terminal

We need to know more about your wiring scheme. You should be using common ground with phased transformers - are you? If so, you are likely unable to use the C-D posts on the KW as those 14V posts don't jive with using U as the common ground.

With AC, polarity (and phasing) is important just as in the DC world.

Ok, here is the KW terminal voltage diagram from an old Lionel Manual:

Fixed Voltage

C-D 14v

C-U 6v

D-U 20v

Variable Voltage:

A-U 6-20v

B-U 6-20v

A-C 0-14v

B-C 0-14v

What would be the best plan with this setup?

I was planning on using A-U / B-U for train control And C-D for accessory control. Do I need a separate transformer for accessory control?

 There are two or more releases of 153ir.

  If there is no continuity between the 153 lock-on track clips and acc. outputs of the 153 when switched to aux , then you can use it on a semaphore & banjo. (power it up t   o check

  If switched to Aux. and there is still a path from the lock-on to the aux outputs you would need to isolate the lock on clips from the rail with card stock or tape. and possibly have to jump from the "aux in"(14v C-D) to the clips.

 The whole point is to 100% isolate this signal system to use the 14v because the transformer is tapped uniquely. No portion of the signal system should contact other power supplies.

I can't find a schematic to know.

Sorry the composer froze... power it up via aux, disconnected from track, switched to aux, then test center rail lock-on to aux + - for continuity, then from the outer lock on clip.

...clip to the aux outputs..

There...done... time to do an update I bet 

So If I am reading this correctly, if I just  connect the A/U terminals of the 153IR to the 14vC-D terminals of the KW and there is no connection to the track anywhere in the circuit, I should be good to go?

If the 153IR is totally isolated, along with the accessory, that should work. I don't know, nor has anyone else here claimed to know that the 153IR is isolated, and that gets even further compounded with the existence of at least 2 revisions of the 153IR. At this point, I view it as a try it at your own informed risk.

Ok, in the interests of science (and I am a scientist...) I decided to take one for team and put the theory into practice. I hooked the “A” terminal of the 153 to the “D” terminal of the KW and the “U” terminal of the 153 to the “C” terminal of the KW. The track was wired “A” of the KW to the outside rail and “U” of the KW to the Center rail. I then hooked up my Semaphore to the 153 outputs and fired everything up.  It worked!!!! I then tested it further by hooking the center rail to the “C” terminal of the KW and it still works.

Thanks for all the input!

Kevin

   Kevin, a muti-meter (ohm meter) or even test light would have tested that more safely, and though it works, you should test it to be sure. You are not out of the woods. You must confirm no contact; exactly as guesses, 100% isolation.

(if you don't have one, plan on at least a cheapie. Even a Dollar store analog meter beats nothing. One of the best tools to have in the hobby)

Phasing issues might not rear there heads till the right conditions are met. The condition to be avoided will involve one or both throttle use and the result would be no voltage , double voltage or somewhere in between.  

For the basics on phasing transformers, from which you could at least grasp at what might happening, search YouTube for "phasing lionel transformers" and look for the Lionel corp. video. Mike Regan did a good job at keeping you awake during his "science class", and keeps it pretty easy to grasp.

Hi Adriatic,

Yes, I have read the article on phasing transformers and grasp the concept of correct phasing with AC power and yes, I do own a good multimeter and will perform the test you suggested.  However there is one more piece of information that may not be apparent which may put your concerns at rest, I do not have the lock on power leads to the 153 connected to anything.  The SOLE power input to the 153 is power leads from the C-D on the KW to the A/U on the 153.  I do not plan on dual powering the unit and if, for some reason I did, I could see your concern for isolation.

In case you are concerned about an issue with the transformer, I did hook up my multimeter to the AUX input and output leads  of the 153  and check the voltage and it remains constant despite operation of the throttles.

thanks,

Kevin

 Sweet! You nailed it.

Kverdon posted:

...The track was wired “A” of the KW to the outside rail and “U” of the KW to the Center rail...

Using "A" as common is going to produce some unexpected results in your wiring.  Some voltages will go down as you advance A up.

Items connected to C & D only won't be affected, but when you use the direction control or whistle control any switch or accessory connected to A as common will shut off, or be activated by the whistle/horn circuitry with the DC offset, respectively..

Rob saves the day as usual

Guys, please focus on the following the ONLY power going to the 153 comes from the C-D of the KW. There is NO connection from the 153 to track power. The voltage, as measured by my Klein Multi-Meter at the 153 power inputs is static, irreguldless of the manipulation of the 2 KW throttles.

Kverdon posted:

Guys, please focus on the following the ONLY power going to the 153 comes from the C-D of the KW. There is NO connection from the 153 to track power. The voltage, as measured by my Klein Multi-Meter at the 153 power inputs is static, irreguldless of the manipulation of the 2 KW throttles.

ADCX Rob posted:

Items connected to C & D only won't be affected...

 C-D is in fact a fixed voltage, and circuit breaker protected.

It works as is for C-D.

  But he is right.   And anything modern would have bell vs a whistle too (assuming correct whistle diode/disc installation)

You likely knew this, but it's worth mention for those lurking.