Converting American Flyer to DC operation.

[Railroader_Sailor_SSN-760]

All,

The E-unit on my Flyer Blue Comet Alco has finally stopped working. Somewhere inside of it has a short that will not let the loco run. It runs with the E-unit bypassed, but that only allows foward only operation, of course.

I have about a dozen other Flyer steamers that have dead or near dead E-units with working motors. 

Then there are a few more with bad motors, and a couple with no motors at all. 

For those with no/bad motors, I am planning on replacing them with can style motors, which would make another point for converting to DC.

I remember hearing something about converting American Flyer to DC will make for a stronger pulling engine. 

Does anyone out there feel like explaining that for me? Thanks.

What kind of a modification would I need to make to run the locos in DC. I know most of gilbert's motors are of the universal type, so that should not be hard.

That and the fact that DC makes control easier (no E-units, direction by polarity, not by swapping windings via e-unit) which would make for easier yard operations.

Thanks,

 

James

 

[lionelsoni]

To convert a universal motor for DC, power either the field or the armature (but not both)through a bridge rectifier, with the + and - terminals of the bridge connected to the armature and the ~ terminals in series with the field, or with the + and = terminals connected to the field and the ~ terminals in series with the armature.

I wouldn't expect it to pull any better on DC.  If this has a bearing on your decision to convert, just try running it on DC as it is.  The DC performance will be the same with or without the e-unit or rectifier.

[Railroader_Sailor_SSN-760]

I remember seeing and article in CTT about someone's Flyer layout and made mention that the conversion allowed for longer trains.

Right now this is just on the drawing board, as I do not have a powerful enough DC power pack to run much, the basic set power pack for an HO scale set bearly provides power for a trio of small HO engines, much less a single S loco.

Since I need to get a new power pack for my G scale train set, I could also see if it would help with the Flyer equipment.

Thanks

James

[spikejones52002]

You can run an A.C motor on D.C.

You can not run a D.C motor on A.C.

 

Problem is that you can not reverse the direction of the A.C motor like you do with a D.C. Motor.

You still need the field reversing unit. 

[Sturgeon-Phish]

On your locos with a universal motor, which most of the AC Gilbert American Flyers are, to run them on DC you do not need to do anything.  You can literally take a universal motor off an AC track put it on a DC track and it will take right off.

To convert your AC transformer to DC you can use a # 15 electronic rectaformer, then change directions using the direction switch.

It works really well.  As far as having more pulling power I can't say.  Running on DC does cut down on the noise from coils like in the 977 caboose

Jim

[lionelsoni]

It is true that you can run a universal motor on DC without any modification.  That is why it is called "universal".  If it has no e-unit, it will always run in the same direction, whether powered by AC or DC.  If it has an e-unit, it will reverse in the same way on DC as it does on AC, stepping through the forward-neutral-reverse pattern.  All of this is the reason that I suggested trying before modifying to see whether the performance on DC is satisfactory.

Putting a bridge rectifier into the locomotive in the way I described, to replace the e-unit, will change the behavior of the motor.  It will no longer be "universal", in that it cannot be operated with AC, but will acquire the sensitivity to polarity that a permanent-magnet-field "can" motor has.  Its performance will otherwise be unchanged.  Then you can control direction by reversing the polarity of the track voltage.

You can use an authentic American Flyer "rectiformer" or "directronic rectifier" to get your DC.  But these are simply silly and pretentious trade names for selenium bridge rectifiers used with transformers.  You can get your own silicon rectifier easily at Radio Shack.  Although the 4-ampere rectifier (276-1146) is plenty for use in the tight spaces of the locomotive, I suggest using the 6-ampere (276-1181) or 25-ampere one (276-1185) with the transformer. 

[Sturgeon-Phish]

Bob,

That is interesting.  I knew what the #15 did, but I did not know how it did it.  Thanks!  But you have to admit the #15 looks way more cool than a rectifier

Jim

[spikejones52002]

NO, NO, NO

Adding a rectifier to a universal motor will not do a thing to help reversing your motor.

The #15 rectifier was made for the couple of D.C. engines that American flier made. The reversing switch on it will not change the direction of the A.C. motor. 

I do have Electronic reversing units for A.F and Lionel engines. They are $40.00 each and come with directions.

[e-mail] 

[lionelsoni]

Sure it will (if you do it the way I described).

The reason for a universal motor's not reversing with the supply voltage polarity is the same thing that allows it to run on AC.  That is that both armature and field currents reverse simultaneously whenever the supply voltage polarity reverses.  A permanent-magnet motor's field is produced not by the supply voltage but rather by the permanent magnet, which never reverses its polarity.  So the reversal of the supply to the armature changes the polarity of the armature current relative to the field, which reverses the motor.  The e-unit also reverses that relative polarity, to reverse the universal motor.

A rectifier in the locomotive, supplying only the field of a universal motor, insures that the polarity of the motor's field never changes--just as it never changes in a permanent-magnet motor.  Then reversing the polarity of the track voltage does reverse the armature-current relative to the field current and does indeed reverse the motor.  (The same is true if the on-board rectifier supplies only the armature.)

A simple way to handle an AC-to-DC conversion in a Lionel locomotive is to think of the rectifier as replacing the e-unit.  Suppose that the wires to the e-unit have the typical colors of yellow and blue for the armature, green for the field, and red for the pickup.  Just put the yellow and blue onto the + and - terminals of the bridge rectifier, and the red and green onto the two ~ terminals.  (No ground connection is needed.)  If the motor runs the wrong way compared to your other DC locomotives, swap the yellow and blue wires.

(Please note that I have no rectifiers to sell, which would be a violation of forum policy.)

[brianel027]

Sorry Spike, but Bob is correct on this one. Now, maybe not on AC current, BUT adding a fullwave bridge rectifier to an AC open frame motor (wired in one of the ways Bob mentioned in a prior posting on this topic) WILL WORK provided you use a DC power pack to run the loco. Or an AC transformer wired with a DPDT switch and a full wave bridge rectifier. The Double Pole - Double Throw switch controls the direction in either forward or reverse.

It works because I've done it.

[lionelsoni]

Thanks for the eyewitness testimony, Brian.

[spikejones52002]

I am not the one who will say that will never work!

They told that to Edison and look what he did. 

I am going to pull out one of my engines and attempt it.

I see the basic theory as you describe it.

[lionelsoni]

Good for you!

Here's another wrinkle:  With 2-rail American Flyer, DC-polarity reversing works especially well because you can use multiple locomotive units without worrying about which way they're facing.  (The HO standard is that the locomotive moves forward when the right-hand rail is positive.)  If you pick up a 2-rail locomotive that is running forward, say, north, with the east rail positive, turn it around and put it back on the track, it resumes going north.  This happens because rotating the locomotive swaps the rail-wheel connections, causing it to change to running backwards.  But backwards is now north!  So you can mix units facing in whichever direction, and they all agree on which way to go.

However, with three rails, the polarity swap does not happen when you turn the locomotive around.  So, for example, two identical F3 A units coupled back-to-back will perform a tug-of-war or a shoving match, getting nowhere.  It is therefore useful to be able to change the polarity some way or other on the locomotive.  You could do this with a DPDT switch in the wires to the armature.  Or you could leave the e-unit in place and wire the bridge rectifier in the yellow and blue wires between the e-unit and the armature, with the ~ terminals facing the e-unit and the + and - facing the armature.  Then you can turn one locomotive's e-unit on and step it until it matches the other one, then switch it off and control direction with DC polarity from the rectifier at the transformer.

Another consideration:  Getting DC from a multiple-output transformer, like a Z or ZW, is problematical.  You need to use a separate bridge rectifier for each output; but the DC results no longer have a common return.  So running multiple trains on DC works best with separate single-output transformers.  Then the DC outputs, downstream of the reversing switches, can be connected together to form the common return, connected to the outside rails.

[J. Daddy]

All,

The E-unit on my Flyer Blue Comet Alco has finally stopped working. Somewhere inside of it has a short that will not let the loco run. It runs with the E-unit bypassed, but that only allows foward only operation, of course.

I have about a dozen other Flyer steamers that have dead or near dead E-units with working motors. 

Then there are a few more with bad motors, and a couple with no motors at all. 

For those with no/bad motors, I am planning on replacing them with can style motors, which would make another point for converting to DC.

I remember hearing something about converting American Flyer to DC will make for a stronger pulling engine. 

Does anyone out there feel like explaining that for me? Thanks.

What kind of a modification would I need to make to run the locos in DC. I know most of gilbert's motors are of the universal type, so that should not be hard.

That and the fact that DC makes control easier (no E-units, direction by polarity, not by swapping windings via e-unit) which would make for easier yard operations.

Thanks,

 

James

 

James,

I have been running American flyer AC for a while, with very little issues. For your Blue Comet I would look at repairing your E Unit. If I lived closer to you I could rebuild it in about 15 minutes, usually the short is in one of the bent fingers on the drum. But I tell ya if you polish the drum, replace the fingers and use some light machine oil to lube the arm and drum up you will have a very reliable running locomotive. Are you good at soldering? I would give one a try to repair, follow a good repair manual, after the 3rd of 4th loco you will be an expert.

The AC to DC conversion is a myth,  you will get the same pulling power with the same Gilbert Universal motor in AC or DC.  Now if you change to a Can Motor with flywheel then your talking an upgrade, they draw fewer amps and the stored energy from the flywheel will make your locomotive run like night and day. This upgrade is relatively expensive and very time consuming. I am not even aware if there is a kit out there that will simplify things. Note that the mounting plates will have to be machined from scratch, and a proper worm gear may have to be bought to optimize the rpm's of the can motor.

Your best bet here if you like S gauge.... American flyer toy train collectable - keep them that way - if you need a good locomotive with scale stop and start speeds for yard switching, check out American Models, or S helper they make AC and DC versions... you will be blown away, and of course so will your wallet (once you have one you will want another), but this way you can have your scale speed locomotives for switching and still run your PW American flyer trains on the high iron.