# Questions on AC / DC Transformers and Locomotives



## Srook (Jan 3, 2013)

I had purchased a Lionel starter set in the late 1980s; Freight Flyer with an 8902 locomotive and a 4660 transformer. I hardly used it and really never got into Lionel trains much. I got it out this Christmas to run around the tree and it worked great. My kids want me to build a layout and I have been interested in post war Lionel stuff. 

I bought a 221 with the 221T tender. I disassembled and cleaned it after reading a bunch of posts on this forum and online. It runs great on my Christmas set but only for a few minutes. I hear the 4660 transformer click and then the 221 stops. I immediatly try the 8902 and it does not run either. I have to wait a few minutes or knock on the top of the 4660 to get either going again. I think the 221 needs more power than the 4660 can give it and I think there is an AC / DC issue going on. A few questions:

Should the 221 run continuously with the 4660 transformer or do I need something that is AC?

If I get a new AC transformer can I run the 8902 locomotive on it or does it need a DC transformer on its own track?

Finally, the 221 needs a replacement valve gear assembly but otherwise is in decent condition with some paint chips and scratches. Can I touch it up or should I be looking at a complete strip and repaint? Will a repaint destroy the value or does it not really matter?

Thanks for any help.
Scott


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## tjcruiser (Jan 10, 2010)

Some general answers ... (I'm not that familiar with specific modern models). But you are right ... Lionel made true DC-powered trains for a while 1970's/80's.

AC locos will run on DC track power, though you'll need a bit more power to get equivalent speed. I don't think the locos auto-reverse e-unit will work on DC power, though. You need AC for that. (Correct me if I'm wrong here, guys!) If I'm right, your e-unit is likely stuck in the neutral position. Turn the loco upside down and rightside up once or twice. This will move the plunger up/down, which will move the e-unit drum to a forward position. (Trial and error here.) Then, move the e-unit lever over to the other side to disengage the e-unit.

You should NOT (!!!) try to run DC locos on AC track power ... you'll fry 'em! Stick with DC power, or .. with a bit more effort, you can install a "bridge rectifier" that will onboard convert the AC power to DC (more or less) before it goes to the motor itself.

Is the 221 black? A black Sharpie can fill in many small dings/chips without looking too crude. After applying the Sharpe, wait a few moments, then rub the area with your finger ... it'll help to remove the Sharpie's "purple sheen".

I've recently stripped and repainted a 221 ... came out quite nice. Did it affect value? Well, I'm really not concerned one way or the other ... the loco is mine to keep, and its new skin makes me happy. (That ... plus I bought the thing for only 35 bucks, I think!)

My 221 thread, here ...

http://www.modeltrainforum.com/showthread.php?t=3483

TJ


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## servoguy (Jul 10, 2010)

I have used the Sharpies to retouch many locos and tenders. The purple sheen will disappear after a while. 

A conventional E unit should work OK on DC. The coil might get a little hotter than on AC because the current will be higher.


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## T-Man (May 16, 2008)

The easy solution is two trees or two circles. The work required to install an electronic e unit in the engine. For the quality you are better off getting another engine, I got lucky and found a junker with an e unit and transfered it to a switcher. It is an overkill to do it for a Scout. 

I don't have much practical experience running AC trains on DC. The manual says they do both. I think the e unit becomes magnetised with DC.

The armature of a DC motor goes into a resonance when AC is applied, so it does not spin. I haven't burned one yet but I now recognise the chatter by sound.


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## gunrunnerjohn (Nov 10, 2010)

You want to add resistance if you run the E-Unit on DC as the coil gets pretty hot, I've tested one that way.  Also, as T-Man says, eventually the coil will get magnetized. You can cycle it a few times on AC to remove the magnetism.


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## Srook (Jan 3, 2013)

Thanks for the replies. I still have some questions about the E unit and what exactly it does. 

TJ your rebuild thread was what convinced me that I could do it too. Thanks.

I saw a youtube video of someone rebuilding an E unit but I still don't know what it does. I have the lever in the 12 oclock position. When I move it to the 2 or 10 oclock positions nothing changes. The locomotive runs forward. But I think that is because I am running with a DC transformer. I did lube the wheel inside the E unit and spun it around with a toothpick. When I turn the locomotive upside down while holding the wheels from moving I hear the drum inside the E unit "thud", so I think it isn't stuck.

I am on the hunt for a relatively cheap 1033. I think I will understand alot more Once I get this 221 running on AC.

Can someone explain the E unit and what it does at which positions?

Thanks
Scott


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## Handyandy (Feb 14, 2012)

Is the circuit breaker popping on the transformer? If it clicks and nothing will run until it clicks again that sounds like the breaker is tripping to me.
The little DC pack may not have enough ooomph to keep the old AC postwar loco chugging along.


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## tjcruiser (Jan 10, 2010)

Srook said:


> Can someone explain the E unit and what it does at which positions?
> 
> Thanks
> Scott


Take a look at my e-unit wiring diagram here:

http://www.modeltrainforum.com/showthread.php?p=41374&postcount=16

The 221 setup is "similar but different". On my 1681E loco, the e-unit flip-flops direction of current through the field coil. On your 221, the e-unit flip-flops direction of current through the armature. The concept is the same, though, and either setup will work. (The former has a grounded brush; the latter has a grounded end of the field coil.)

The e-unit "drum" has 8 positions in a full turn: f/n/r/n/f/n/r/n (fwd, neutral, reverse).

Each time the plunger rises, it moves the gear teeth and drum 1/8 turn. Doing so changes the path of electricity to the motor, per my diagram.

The plunger is gravity-dependent ... loco needs to be upright for it to fall back down with a no-power throttle-down. It's normally up with track power.

The e-units have two sets of little contact fingers. These are often bent out of alignment, with improper contact to the rotating drum. It takes some fiddling, but they can usually be fixed.

TJ


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## Srook (Jan 3, 2013)

> Is the circuit breaker popping on the transformer? If it clicks and nothing will run until it clicks again that sounds like the breaker is tripping to me.
> The little DC pack may not have enough ooomph to keep the old AC postwar loco chugging along.


This is exactly what I think is happening. I will need to get an AC transformer and try it again.

Thanks
Scott


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## Dave Sams (Nov 24, 2010)

Srook said:


> The locomotive runs forward. But I think that is because I am running with a DC transformer.


If you have an AC motor, with an E unit, it will run in the direction the E unit is set. It won't matter if you have AC or DC running in the track. If the AC motor has a bridge rectifier on it, you can control the direction of travel by reversing the direction of the curent in the track.

If the AC motor only goes forward, and the E unit is not set to one direction, and you hear the E unit cycling, I'd suspect some of the contacts on the drum are dirty.


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## servoguy (Jul 10, 2010)

You cannot reverse the direction of a loco that has a bridge rectifier unless it also has an E unit. Reversing the polarity of the voltage to the track will have no effect.


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## gunrunnerjohn (Nov 10, 2010)

Posted in another thread, reprinted here because it seems to answer the question. 


Personally, I buy the electronic reverse unit, they can be had for as little as $15 for the Lionel small one for basic set locomotives. They include the rectifier and three position E-unit functionality. The Train Tender has them for $13.50, part number 8214-51


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