Correct Wiring of a Lionel #1688

[steve1946]

Hi,

Can anyone help me with the proper wiring of a #1688 2-4-2 Torpedo?  A diagram is what I need!  It has been suggested by other folks in the train hobby that the wiring for the motor/e-unit is "a little bit different"  than other later Lionel motor/e-units.  I also found out that a previous issue of CTT had an article about this topic.  Any help will be appreciated.  The Olsen's web-site shows a diagram but I don't believe it is for the #1688.

Thanks,

 

Steve

[cwburfle]

Just a guess: some prewar Lionel locomotives have the lower brush grounded to the frame. One of the brushplate screws goes through the tab connected to that brush. On these locomotives, the field has two wires that go to the e-unit.
If that is the case, the inner contact (pair) on the four "finger" plate goes to the remaining (not grounded) brush tab. The two "finger" contact goes to one field wire. One single contact on the four "finger" plate goes to the other field wire.  The remaining single contact on the four "finger" plate goes to the e-unit's power terminal.

[teledoc]

Steve,  What version of 1688 do you have is the main question?  What does the bottom plate on the motor say, as there are 3 versions of motor, used through the course of manufacture.  The very first issue used a motor labelled Lionel Jr., with 8 spoke wheels.  The second version introduced late 1937 said Lionel 027.  The third version used a motor with a bakelite collector assembly with the circle L.  The motor mounting is different on the progression of 1688 & 1688E's.  The first version from 1936 has screws in the running boards, and the motor plate looks like a wing, which is the 1936 series.  Another version uses a single screw that passes through the body, and threads into the opposite side of the body.  The third version motor is very much like the 1655 motor of Postwar, and used two screws front and back of the motor and passes through the body.

Which one do you have?

 
And the body styles of the 1688/1688E number about 8 different bodies, with different distinguishing characteristics.

[wrmcclellan]

Wiring diagram here:

http://www.olsenstoy.com/cd/b123/000533.pdf

Olsens LIbrary here:

http://www.olsenstoy.com/library.htm

Free to use on-line.

Note in the drawing the lower two fingers on the e-unit are the two fingers on the lower plate and typically horizontal. The four fingers are the vertical set. One can easily see the wires where they attach to the e-unit so you can sort them out.

Good luck!

[ADCX Rob]

While this is typical, it is not always done this way, as some early steamers had brush & field connections reversed. It's easy to tell, one brush would be connected directly the chassis/ground, and both field wires go to the E-unit.

[teledoc]

I am going to presume that you have an earlier version motor, and not the last version that resembles a 1655 Postwar motor.  

The two finger contact with the single wire goes to the outside wire of the field coil. Now looking at the four finger contact board, you have wires on #1, #2, & #4, the third position is empty.  Wire #1 gets wired to the upper brush holder.  Wire #2 gets wired to the inner most wire of the field coil.  Wire #4 is from your collector, soldered to the lever post, and the lamp lead is wired to that.  I have multiple 1688/1688E's.

The very first issue in the beginning of 1936 is unique from all the others, with the body casting having open forward facing windows in the cab, and a square roof hatch on top of the cab.  It also has what some call a winged keystone above the headlight, just under the smoke plate.  That is the rarest of the series of 1688E/1688's.  There was a reprint back in February 2015, from an article by John A. Grams, noting the difference of that loco, compared to the rest of the run.  It is under "Timeless Classics".  I now own three of them.

[steve1946]

Dear teledoc,

Thanks for your reply.  Here is what I have.  The 1688 body has no forward open facing windows and there is no roof hatch nor is there a winged keystone.  The motor mounts to the body with two 2 1/4 inch screws that go through the body.  The motor brush plate has two solder lugs but only the forward lug has been used.  All current bench tests produce a buzz from the motor.  Not a short.  The e-unit cycles fine when tested on the bench.  The electric continuity of the motor is fine.  I'm starting to pull what remaining hair I have on my head out!  What is the correct way to wire this version motor?  This motor will make a large hole in the wall! Thank you very much for your help.  Steve

[teledoc]

Steve, I hope I can explain this correctly.  The motor you have is identical to a Postwar 1654, and the collector plate on the bottom should be plastic with a circle L right in the middle, and sliding shoes.  With the brush plate side of the motor facing you, the right brush holder should be grounded to the frame of the motor with the mounting screw.  You have to make sure that the brass part of the brush holder is caught under the screw head, for ground continuity.  No wire gets attached to the right side brush.  I don't know if your E unit is color coded with Blue, Green, Yellow, & Black wires, but looking at the 4 finger contact, where the wires are facing you, count from left to right, as 1, 2, no connection, 4.  The power from the collector assembly w/lever on E unit, gets connected to #4.

#1 wire from E unit gets connected to the left side brush.

The two finger bottom contact (typically yellow) gets connected to the field coil closest to the brush plate.

#2 wire from E unit gets connected to the opposite side of the field coil.  I have a motor, just like yours, but it doesn't have an E unit in it, when I bought it.  It is basically hardwired, and I just haven't had the time to install an E unit.  If you have the wires disconnected from the E unit, to test the motor simply take a jumper from the left brush to the front coil wire.  Connect your transformer leads with one to the frame (grounded side), and take the other lead to the opposite coil wire, and turn up the voltage.  It should run.  If it doesn't, check that the right side brush (brass tab) is securely grounded.

I hope you understand my explanation.  Your motor was the last version, used in the 1688.  There are three distinct motors, that were used throughout the years and how the motor is mounted tells which one is which.  1st motor mounted with 2 vertical screws through the running board (Lionel Jr. motor), 2nd version had only one screw that went laterally through the body, near the cab, and the motor would have a hole on both sides of the motor for the screw to pass through.  3rd version is what you have, with the motor that is identical to a Postwar 1654 motor, and used two screws to mount the motor, passing through the body, one forward and one rearward.

[teledoc]

Steve,  Have you tried anything that I suggested, to test your motor.  You haven't replied since my last posting.  It is pretty straight forward to test the motor.  To make sure the motor is functional, disconnect the E unit from the motor, so that all you are dealing with, is the motor by itself.  The field coil is on top with two solder connections.  Jumper the left side brush holder to the solder connection closest to the brush plate.  Make sure that the right side brush holder is securely under the mounting screw that attaches the brush plate to the frame.  That is your ground return path, and the right side brush is the common (ground).  Take your transformer leads, and connect one lead to the frame, which is GROUND, and connect the other lead to the solder connection (field coil wire on the opposite side of the motor.  Crank up the voltage, and the motor should run.  If it doesn't run, then there is more problems with the motor.  (Possible bad armature/shorted or one segment grounded to the armature shaft, or an open winding on one of the segments.  The motor is nearly identical to the Postwar 1654 motor.

I only have a Simpson 260 analog, but the coil resistance is .7 ohms, on the motor I have, which is the same one as yours.