Replacing Dummy Couplers/ and Issues on an O27 switcher engine?

By the way, what is an E-Unit Lever?  Is it a physical 3- position lever that sticks out of the top or back of the engine, which you manually move from forward, to neutral to reverse?  Or is it something else?

If is the physical lever, can't you just leave the lever in the forward position, and make the engine go in reverse by hitting a reverse polarity switch on the power supply to the tracks?

Thanks,

Mannyrock.

Need more info on the engine in regards to the couplers. Some can be retrofitted with operating couplers, some not. Underside picture?

The switch is off, on for the eunit.. the e unit cycles fwd,n,rev. Shutting it off "locks" it in F,R,or N if it has N. If turned over, it may cycle the mech on gravity.

(a test bench trick too)

CRC electrical contact cleaning spray, Wallmart to Autozone

Grease may be hard and chunky, hard to say.

A smooth motor sounds like "You" if you trust the seller that far. It's your wallet, but 20-30 is about right for a "buy it at the moment" replacement motor. (Diesel right?)

I mostly loop and would survive too.

Sorry for my stupidity, . . . but I still don't get it.

Take for example a Lionel Scout engine, with the 3  position lever switch on the top.

If the lever is forward, it will run forward.  If I leave it on forward, and reverse the polarity on the AC lines running to the track, doesn't it HAVE to run the motors in reverse, causing it to back up?

Or, is there some electrical stuff here I just don't get, and the engine will burn up.  :-)

Mannyrock

Adriatic explained the lever for the e-unit correctly IMO. That lever for a Lionel 027 diesel switcher is probably on the bottom. Just try running the engine with that lever in different positions and then you will understand if it works and, if so, how it works. Arnold

A dummy coupler will pull your train just fine. The only issue with a dummy coupler on an engine is that if you want to uncouple you will have to use the uncoupling mechanism on the adjacent car, not the engine.

@Mannyrock posted:

Sorry for my stupidity, . . . but I still don't get it.

Take for example a Lionel Scout engine, with the 3  position lever switch on the top.

If the lever is forward, it will run forward.  If I leave it on forward, and reverse the polarity on the AC lines running to the track, doesn't it HAVE to run the motors in reverse, causing it to back up?

Or, is there some electrical stuff here I just don't get, and the engine will burn up.  :-)

Mannyrock

By nature you can’t reverse the polarity of AC current, that’s what the reverse unit is for.  In older AC motors, the reverse unit changes how the current is passed through the motor to reverse it vs a DC motor with permanent magnets where a simple change of polarity when running on DC current changes the direction.  Leaving a scout in the forward position and changing the power feeds won’t cause it to run in reverse.

OK.  I think I've got it.

But, . . . if you have a transformer, putting out AC current to the track, and the transformer has a direction switch on the face of it, and you flip it, how does that make your engine run in reverse?       (I thought that the direction switch on the transformer was just a reverse polarity switch.)  

Now I've got it.  Thanks

Mannyrock

Oops, please ignore the final "Now I've got it" phrase in my prior post. It was a stray thought and should have been deleted.  

The direction button on the transformer just interrupts power to the track. This interruption causes the 'E' unit to sequence if the 'E' unit lever is set to allow the 'E' unit to sequence. The contacts and drum of the 'E' unit are wired to the motor in such a way as to change how electricity is fed to the motor. When sequenced, the 'E' unit will allow the motor to run first in one direction, sequenced again the motor will be in neutral, sequence once again, the motor will run in the opposite direction, and finally sequenced one more time, the motor will be back in neutral.

AC voltage does not have a polarity; only DC does. Reversing the connections from the transformer to the track will not reverse the direction of the locomotive.

You can try spraying a little solvent into the 'E' unit to try and free it up if it sticks. Failing that, a complete rebuild is probably in order. See here, part 1, and here, part 2,  for a complete video tutorial on rebuilding 'E' units.

Larry

On an AC transformer, the "reverse" switch merely interrupts the current flowing to the track momentarily. It does no more than turning the track power off and then on again.

The actual reverse unit, or "e-unit," is in the locomotive. It is basically a switch that cycles one position each time power is applied to the track. Because this switch changes position only on power up, to operate it, you have to cut power to the train and power it up again. That is what the "reverse button" on the transformer does.

The locomotive reverse unit has a lockout lever, or a sliding lockout switch. The lever is found on locomotives where the reverse unit is an electromechanical switch; for whatever reason, this lever is always made of nickel plated metal. The slide switch is found where the reverse unit is a circuit board. In both cases, the lockout prevents the reverse unit from changing position when power is applied, so the train will maintain the direction it was last moving in before you threw the lockout switch, even after a power interruption.

Locomotive reverse units are broadly divided into three-position (forward-neutral-reverse) and two-position (forward-reverse). The modern ones with the electronics are all going to be three-position. For the older type with the nickel-plated lever, one way to tell which is which is to look at the slot the lever rides in. On the two-position, the slot is cut in an arc. On the three-position, it is straight.

There are some low-end engines which have no reverse unit at all. In these, the reverse lever on the engine actually changes the direction. It looks the same as a two-position electrical reverse, so the only way to know for sure is to do your research.

The Lionel Scout (I mean a Scout from the postwar period, not a modern remake) has a two-position reverse, but internally it is a totally different animal than the others. Too much different to explain here. You can identify them by a stubby, thick lever (almost always black fiber or plastic) in a straight slot cut fore and aft (not side to side) in the top center of the locomotive casting. All Scouts are small steam engines.

A common problem on the three-position type with the nickel-plated lever is that the reverse unit does not cycle when power is interrupted and re-applied. On these, if you listen, there is a metallic "click" sound when power is cut--it is the sound of the electromechanical reverse unit moving to "home" (literally, a plunger falls by force of gravity). If it fails to do this, then the direction will not change when power is re-applied. This is what people mean when they talk about a "sticky e-unit". There are many posts and magazine articles about how to fix a sticky e-unit. Squirting it with tv-tuner / electronics cleaner is usually one of the first things you try.

Hope that helps!

I think nick covered it pretty well.

@Mannyrock posted:

. . . if you have a transformer, putting out AC current to the track, and the transformer has a direction switch on the face of it, and you flip it, how does that make your engine run in reverse?

Here is the Owners Manual.

As I upgraded older Weaver models to TMCC control, and added electro-couplers,  these are in the parts box. 

A compound, double movement Atlas coupler used in their SW switchers. 

TrainLarry and Nick,

WOW.  NOW I get it!

Thx,

Mannyrock

Lol, ready for another wrench Manny, "Scouts" come in a large variety. Some of it is just slang pointing at a small or low cost train. You can argue it's how it was marketed by.lionel that counts and you're right, but common vernacular means you might be wrong, lol.

The Scout may be different if it has one of the 50-60s plastic frame motors.

Those phsically move the field coil a little, changing the position of magnetic pulls as they happen. (there is some "timing" in our motors too, similar to auto ignition timing effecting their running. )

Half the eunit is mechanical.  The motion of the coil is switched by the lever.  The coil moves a hook up and down, that hook catches rachet teeth on a drum equipped with a set of cam contacts and contact arms. (like a wind up music box/jack in a box)

One ac cycle contains two + & - waves.  Each of those wave halfs is one pulse of dc. One pulse of dc+ and one pluse of dc- .  I.e. the electrons move back and forth fast with ac. On dc they move only one direction either + or - .

Ac waves are easy to recognise in "osiliscope form" but most folks never see dc or learn how they compare.  Seeing ac and dc+ and dc- and for a comparison is suggested (an easy look online)  A O-scope it just a simple volt graph +/- for the vertical, horizontal is the amount of time it took. An O-scope scrolls the time, or freezes a moment for you.. Really simple. I think the eerie green ones scared most folk.