American Flyer - 4 Wire Jack Panel

[richhotrain]

I am trying to understand how the 4 wire harness functions on an American Flyer #312 steam engine.

Looking at the reversing unit in the tender, can someone explain to me what function each wire performs once power is present on the chassis from the front and rear trucks. 

The 4-wire diagram is illustrated in the attached link:

http://www.portlines.com/portlinesclinic10.htm

Also, to test the motor in the engine, the tender is disconnected from the engine by removing the jack plug connection.  Then, the two inside wires on the engine jack panel are jumpered together and the two outside wires on the engine jack panel are wired to the transformer, as illustrated in the attached link.  What exactly is being done with the wiring in this situation?

http://www.trainweb.org/s-trains/diagram/jumper.gif

As I mentioned, I am really trying to understand these wiring diagrams and any help would be most appreciated.

Thanks.

Rich

[lionelsoni]

I'll take a swing at it:

The motor has two electrical parts, the field winding and the armature, which is accessed through the two brushes.  To run the motor, you connect the field and the armature in series, then apply the track voltage across this series combination.  The direction of the motor depends on which way the current flows in the two parts.  Reversing the current by swapping the terminals of either part reverses the direction.  The reversing unit does this by reversing the connections of the field winding.  (Lionel motors accomplish the same function by reversing the armature--either way works.)

The headlight is connected across the brushes.  So a little of the current that would otherwise have gone through the armature is diverted through the headlight lamp.

With the plug connected, you can see that one of the brushes is connected to the front truck.  The other brush goes to one of the reversing-unit fingers.  Both ends of the field winding go to reversing-unit fingers.  And the last finger goes to the rear truck.  The drum rearranges the connections among these 4 fingers to wire the field winding in series with the armature and to complete the circuit through it to the rear truck.

The reversing-unit coil is simply wired between the front and rear trucks.

The jumpering that you described just connects the two parts of the motor in series.  I count 4 different ways that this could be done, 2 of which would make the locomotive run one way, 2 the other.

The 5-wire scheme is the same, except that the fifth wire allows the lamp to be connected directly between the front and rear trucks.  The main difference in operation is that it will be on in neutral.  There is an alternate way to wire a locomotive, using only 4 wires, so that the headlight will be on only in the forward direction.  This works with Lionel motors and, I think, probably would with Flyer too.

[Sturgeon-Phish]

Bob,

You've got it!  On page 16 of Tom Barker's Greenberg's American Flyer S Gauge Repair and Operating Manual (a very good book), is a diagram of what you just put into words.  I'll see if maybe I can post the diagram later this week.

Jim

[richhotrain]

Sturgeon-Phish

Bob,

You've got it!  On page 16 of Tom Barker's Greenberg's American Flyer S Gauge Repair and Operating Manual (a very good book), is a diagram of what you just put into words.  I'll see if maybe I can post the diagram later this week.

Jim

Jim,

I will look forward to seeing that diagram you refer to.  Thanks.

Rich

[richhotrain]

lionelsoni

I'll take a swing at it:

The motor has two electrical parts, the field winding and the armature, which is accessed through the two brushes.  To run the motor, you connect the field and the armature in series, then apply the track voltage across this series combination.  The direction of the motor depends on which way the current flows in the two parts.  Reversing the current by swapping the terminals of either part reverses the direction.  The reversing unit does this by reversing the connections of the field winding.  (Lionel motors accomplish the same function by reversing the armature--either way works.)

The headlight is connected across the brushes.  So a little of the current that would otherwise have gone through the armature is diverted through the headlight lamp.

With the plug connected, you can see that one of the brushes is connected to the front truck.  The other brush goes to one of the reversing-unit fingers.  Both ends of the field winding go to reversing-unit fingers.  And the last finger goes to the rear truck.  The drum rearranges the connections among these 4 fingers to wire the field winding in series with the armature and to complete the circuit through it to the rear truck.

The reversing-unit coil is simply wired between the front and rear trucks.

The jumpering that you described just connects the two parts of the motor in series.  I count 4 different ways that this could be done, 2 of which would make the locomotive run one way, 2 the other.

The 5-wire scheme is the same, except that the fifth wire allows the lamp to be connected directly between the front and rear trucks.  The main difference in operation is that it will be on in neutral.  There is an alternate way to wire a locomotive, using only 4 wires, so that the headlight will be on only in the forward direction.  This works with Lionel motors and, I think, probably would with Flyer too.

Bob,

This is a tremendous help to me.  I appreciate your taking the time to write it.

Incidentally, I tried all four combinations of the jumpering that you indicated and, indeed, they all work as you say - - two forward and two reverse.

Thanks again.

Rich