Lionel train question

Have you line isolated your variac? If not then you had a serious ground loop flowing from the power mains to the power supply ground and that was your original problem.

As I understand it, the DC was in parallel to the AC, but a separate supply. No filter capacitors - Raw DC only straight from the bridge rectifiers should work fine. A very simple circuit suitable for the

1930s when this was first implimented as I understand. It might even been as simple as putting the bridge across the AC output momentarily causing the horn to blow, and the train to slow down. A Double Pole Double Throw switch would do that.

There is (was) a train shop in Toronto called Georges Trains on Mount Pleasant (was there five or so years ago, haven't done a search) and they were big on Lionel stuff and can easily answer the question if you can't find anyone else.

John :-#)#

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Thanks for your reply John. Yes the variac was isolated by means of an isol ation transformer ahead of it. I essentially did what you mentioned. That i s, I assumed that the DC output was placed in parallel with the AC train v oltage, and did that from my DC bench supply. That's when I noticed the hug e current draw on the DC supply. I was questioning if that was normal. Lenn y.

In that case then the DC supply was essentially shorted out by the secondary winding of the Variac.

I am pretty sure the only way this could work is as I described where the AC/DC is switched back and forth with a DPDT switch - both voltages can't be present at the same time.

John :-#)#

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        "Old pinballers never die, they just flip out."

The locomotive motor should work fine on DC. So, just switch the track between AC (loco only) or DC (loco plus whistle). My guess is the ancient system just placed a selenium rectifier in series with one transformer wire to go to pulsating DC. So, you ought to try putting a silicon rectifier in series with your transformer. The way this works, as far as I know, is you SUBSTITUTE pulsed DC for AC, not ADDING DC in series with AC, as you tried. That probably put too much voltage on the motors. The pulsed DC in the Lionel transformer may cause saturation of the iron, and it may start buzzing or overheat. If that is the case, then you'd need to put a bridge rectifier between the transformer and the track, so the transformer still sees AC only. I seem to recall the Lionel transformers with the whistle function had a warning on them to only use the whistle for 10 seconds per minute or something like that.

Jon

Anything useful in Fran's video here?:

On Sunday, February 2, 2014 11:35:58 PM UTC-6, snipped-for-privacy@gmail.com wrote :

n, however with so many talented people out there who subscribe to this gro up I was hoping that someone would either know the answer to this or perhap s be able to direct me to a more appropriate group. Some time ago I picked up a box of old mid 1950's Lionel trains, track, two small adjustable train transformers and some accessories. I just got finished going through the e quipment, and with the addition of some new parts and labor have restored e verything to good working order once again. The engine is a 2055 and it is married to a coal tender that has a whistle inside of it. The train motor o perates on 0 - 16 VAC, but the whistle in the tender, (which is a small fan motor which blows air through some portals), I am told operates on DC. Thi s DC voltage is somehow superimposed on the AC. The correct transformers fo r this set have levers that you would move to apply the DC to the track, op erate the tender motor and blow the whistle, and would be either the KW or the ZW, neither of which came with the equipment in the box. After completi ng repairs, I confirmed that the tender whistle was working by taking the t ender to a train show and trying it out on a test track. Since the small tr ansformers included with this set get hot and are too small I've been using my bench variac through an isolation transformer to test the train. I trie d to see if I could blow the whistle by connecting my DC power supply to th e track, but the current peaked at over 6 amps and took out the power suppl y fuse twice. The variac didn't like it either and started to growl. I figu re the train motor as well as the transformer secondary must be loading the DC supply heavily, and perhaps vice versa. I'm not really sure whats happe ning here. I subsequently found a larger transformer at another yard sale w hich is able to handle the current required to run the AC motor in he engin e, but there is no whistle provision. I've set the train up in the play roo m temporarily with the larger transformer but it would really be nice if my 4 year old grandson could hear the whistle blow. Is it possible when the w histle is blown that the DC is being placed in series with the AC? Sounds c razy but I never tried that. This couldn't be very complicated. What am I m issing here? Thanks, Lenny

You can't put the DC in parallel wiith the AC. I would put the DC supply i n series with the AC supply from the transformer secondary that is running the engine. You might have to reverse the polarity of the dc to get the wh istle to work. Let us know if this works. OR, contact a member of your lo cal toy train club and talk to them to find out for sure how this should be connected.

couldn't be very complicated. What am I missing here? Thanks, Lenny

Yes, It's been far too long :)

you have a normally closed momentary switch across a DIODE that is in line with your AC doing to the tracks. Or One could use a knife switch like was done back then!

The motor in the engine should be a universal type, which means it'll operate on either or. But the whistle is DC only..

I also seem to remember there was a polarity requirement and different tricks were used operating different DC items on the engine.

Smoke and noise.! Make sure you use appropriate diode and put a snubber circuit across it, otherwise Mr L could get angry and fully collapse on you at the wrong time!

Jamie

I like the idea of a diode with a NC switch across it. I'd like to try that one first. Regarding snubber circuits, I have used them in the past across arcing contacts in AC switching equipment. A typical configuration was a .

50 ohm wirewound resistor in series with a .10uf cap. What was it you were thinking of for across the diode? Lenny