#4689 Presidents special AC or DC?

[Petes]

Hello all,

I have read the FAQ that explains AC and DC but it does not answer my question.

Is an American Flyer #4698 presidents special AC or DC?   It runs with AC applied but I do not wish to damage it during prolonged running.  Any help would be apreciated.

                                                                             Pete S

[TrainLarry]

   I believe the locomotive has a universal AC/DC motor, allowing it to be operated on either voltage source. Tinplate trains for the most part came with AC transformers, and that is what they were run on. Running it on AC will not harm it; the motor was designed to run on it. A DC only motor will not run at all with AC voltage, and will burn out with prolonged AC voltage applied, unless a rectifier is used to convert AC voltage to DC.

Larry

[BigAl 956]

Correct, if it runs on AC then it runs on AC. If it were a DC motor then it would just hum and not move.

[Petes]

Thanks for the info,

It does make sense to me that a DC motor with AC applied would hum.    Since it actually runs and moves with AC applied I think that I am safe. Great!

Petes

[sir james I]

I'm not a Flyer expert but I believe engines with DC only motors have DC printed after the number on the cab. So if yours is running on AC as stated above your good to go.

S.J.

[BigAl 956]

Sorry, I phrased that wrong. AC motors will run on DC or AC. If it were a DC only motor and you applied AC it would hum as the motor would be reversing itself 120 times per second. Since you tried an AC transformer and it worked you are OK.

FYI, to my knowledge all AF locomotives are AC. The only DC Lionel was made during a failed MPC transition period in the early 1980s..

[lionelsoni]

American Flyer made both AC and DC versions of many locomotives.

There are plenty of AC motors that will run on AC but not DC.  The ones that will run on either are called universal motors.  They have their field and armature windings in series and have laminated magnetic circuits.  Other AC motors, such as induction and synchronous motors, are naturally poorly suited to locomotives, but are now being used in prototype locomotives, along with plenty of electronics.  I believe that some synchronous motors have seen limited use in model accessories. 

[Nationwidelines]

Although Gilbert made both AC and DC motors, your President's Special locomotive is a pre-Gilbert American Flyer item and the Chicago era American Flyer engines were all AC.  That is assuming you have an original prewar President's Special.  However, I believe that all of the reproduction President's Special motors are also AC, with some of the MTH motors being modern can motors that still run on AC.