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I am working on both a 2037 and a 2056 steamer and am having issues. The 2037 ran when I bypassed the e-unit but would not budge with the e-unit. Initially one of the contacts melted to the drum. After cleaning up the drum and straightening the contacts I re-assembled the e-unit and the engine will not run at all. Everything seems fine in the e-unit. I replaced the drum and no change. Now it seems the engine won't run when I bypass the e-unit I just get a hum. Everything in the e-unit looks fine. I get continuity in the field coil and between armature sections (low ohms) with no shorts. 

The 2056 will not reverse. It will go forward but the reverse position acts as neutral. All the contacts appear to be contacting the drum in the e-unit which moves fine.  

Any thoughts as to what I might be missing would be appreciated. 

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I did continuity tests and all the e unit contact fingers are making perfect contact with the drum no resistance and all wires are intact. As i cycle through the e unit steps I measure transformer voltage at the brushes and the field is energized at positions 1 and 5. The brushes are floating on the armature freely and are transmitting voltage to the commutator. Wiring is correct.

I polished the commutator with crocus cloth and now wonder if somehow this damaged the armature or if it was bad to begin with although the engine did run in reverse only at one point. I measure 2 ohms between commutator sections an 20 ohms between the armature shaft and each section which is consistent with a working engine (wires not disconnected) so there are no apparent shorts.

Everything looks fine and it won't run. I must be missing something but I have no idea what.

pull the side rods and make sure nothing is binding the wheels.

unhook the e unit and see if it runs then.

have you tried a different engine on your track to make sure the transformer of track isn't the problem? I've had track problems pop up out of now where, usually a switch or section of track shorting out. I set up my Uncle's train board this christmas, everything ran fine, set up the tree and then nothing. Traced it down to bad wires for the RC track.

Steamer posted:

pull the side rods and make sure nothing is binding the wheels.

unhook the e unit and see if it runs then.

have you tried a different engine on your track to make sure the transformer of track isn't the problem? I've had track problems pop up out of now where, usually a switch or section of track shorting out. I set up my Uncle's train board this christmas, everything ran fine, set up the tree and then nothing. Traced it down to bad wires for the RC track.

I am working on this at the bench so I am not even using track I make hardwire connections. I have other engines that run fine so my setup is OK. 

When I started on this engine I bypassed the e-unit and it ran. Now nothing. And I checked even the resistances between the drum and contacts and it is fine. Everything is clean and pretty. I do notice that now when I try to bypass the e-unit the motor hums and the field winding gets hot. 

I cleaned everything with naptha (lighter fluid) including the motor brushes. Naptha dissolves all the carbon residue and old grease and oil like magic and leaves everything clean and de-greased. The motor is immaculate. The wiring is good I have the wiring schematics as a guide.

I am clearly missing something so until I find anything new I have to keep grinding at it. I once had a problem with a stereo receiver that took me 4 months to find. Just all of a sudden one day I looked at it and saw what was wrong. This is why when I was in banking we always had two different people check figures or whatever because it is extremely difficult for one individual alone to pick up a mistake especially if he caused it. 

What I have done many times with complex amplifier issues is to use a working one as a model to compare voltages etc. I will probably resort to that if necessary. 

The thought of a bad armature I think is unlikely considering all I hear about how bullet proof these motors are - but you DO see enough non working motors around so I don't know. These don't seem like delicate motors that are easily damaged. 

I have a wheel puller so if I decide to change the armature its no problem. In the meantime I'm going to order some new brushes. And maybe an armature LOL.

M. Mitchell Marmel posted:

(nods) What sort of transformer are you using?  Might want to check the output to ensure it's not overvoltage-ing.  

Mitch

Its my "bench" transformer a Lionel 1053 60 watts. I think the horn diode is shot as that don't work but I measure the output at about 16 VAC max. Other engines run fine with it I just did a 2343 F3 Diesel and a few other steamers it works fine. 

Just guessing, but maybe a cold solder joint?  Wire broken inside the insulation?  Brush jammed in its well and not making contact with the commutator??  These motors are stone-simple, E-unit is the #1 source of problems.  If you bypass the E-unit it should almost always run.

Off-topic, but the relay-based drop-in replacement for steam loco e-units is one product that was discontinued before its time :-(

Well it sounds like you know what your doing to see if you armature is good here is a method that will tell you if its good or bad

Lot of words here but its easy and simple as you will see if you try it

As a note when testing only apply a only few volts.

Remove brushplate hook up 2 wires to transformer only apply low voltage then put 1 lead on commutator segement with other wire touch the segment next to it . If it sparks or armature jumps your good do this until you tested all the segments.

Then touch the armature shaft coming out of it with 1 lead and other lead touch a segment there should be no spark do this with all 3 segments.

Now if the above 2 procedures test ok your armature is good .

The spark method of armature testing won't detect a shorted armature winding.  Only if it is shorted to the frame (second test).  If the armature coil windings themselves are shorted to each other (insulation failure) the only true way to test is a growler.   You will get better results testing your armature segments (between commutator bars) if you use an ohmeter set to a low scale.  Again this is not a definitive test but rather shows continuity.  The growler requires the armature to be separate from the motor.

rkenney posted:

You are measuring voltage from one brush to wheels (ground)? (across field)  I wonder if the Naptha dissolves the armature insulation (shellac).  I use Go Jo hand cleaner (lanolin).

Yes voltage from brush to ground. I have washed entire e unit coils in lighter fluid and no issues. Also, the field is not shorted. But that thought crossed my mind too. I had to step away from this thing for a while I'm getting cross-eyed.

Yes I know about the growler. My '54 Olds has a generator and the only way to REALLY test the armature is on a growler. Years ago these places that rebuilt starters and generators all had growlers. Without the growler, the best way to read low resistances is with a Simpson 260 (which I also collect!) but this is a rudimentary test. 

I have other similar motors around I am just going to swap some stuff out if necessary. If this turns out to be something really stupid I am going to feel like a real dummy...

Ted S posted:

@rkenney  What's a growler?  I've never heard of electrical hardware labeled with that term!

You needed to hang out in the garage more!   I practically lived there for a few years.  Still have my armature lathe with the little saw blades to undercut the commutator insulation.   Lotta fun 'back in the day' as the kids say.  (none of em want to get their hands dirty, now)

fisherdoc posted:
Steamer posted:

pull the side rods and make sure nothing is binding the wheels.

unhook the e unit and see if it runs then.

have you tried a different engine on your track to make sure the transformer of track isn't the problem? I've had track problems pop up out of now where, usually a switch or section of track shorting out. I set up my Uncle's train board this christmas, everything ran fine, set up the tree and then nothing. Traced it down to bad wires for the RC track.

I am working on this at the bench so I am not even using track I make hardwire connections. I have other engines that run fine so my setup is OK. 

When I started on this engine I bypassed the e-unit and it ran. Now nothing. And I checked even the resistances between the drum and contacts and it is fine. Everything is clean and pretty. I do notice that now when I try to bypass the e-unit the motor hums and the field winding gets hot. 

I cleaned everything with naptha (lighter fluid) including the motor brushes. Naptha dissolves all the carbon residue and old grease and oil like magic and leaves everything clean and de-greased. The motor is immaculate. The wiring is good I have the wiring schematics as a guide.

I am clearly missing something so until I find anything new I have to keep grinding at it. I once had a problem with a stereo receiver that took me 4 months to find. Just all of a sudden one day I looked at it and saw what was wrong. This is why when I was in banking we always had two different people check figures or whatever because it is extremely difficult for one individual alone to pick up a mistake especially if he caused it. 

What I have done many times with complex amplifier issues is to use a working one as a model to compare voltages etc. I will probably resort to that if necessary. 

The thought of a bad armature I think is unlikely considering all I hear about how bullet proof these motors are - but you DO see enough non working motors around so I don't know. These don't seem like delicate motors that are easily damaged. 

I have a wheel puller so if I decide to change the armature its no problem. In the meantime I'm going to order some new brushes. And maybe an armature LOL.

What you have described is exactly what I would expect if you had accidentally wired your transformer jumpers directly to the field somehow, It will just hum (rather loudly) and it will get warm in short order. I would say you should go back and do a careful review of the wiring to your motor. Just leave the e-unit out of the equation until you figure out why you could hotwire the motor before, but now you can't.

I don't mean to be condescending at all, but do a quick review to make certain when you hot wire the motor, the field is in series with the brushes

fisherdoc posted:

I did continuity tests and all the e unit contact fingers are making perfect contact with the drum no resistance and all wires are intact. As i cycle through the e unit steps I measure transformer voltage at the brushes and the field is energized at positions 1 and 5. The brushes are floating on the armature freely and are transmitting voltage to the commutator. Wiring is correct.

I polished the commutator with crocus cloth and now wonder if somehow this damaged the armature or if it was bad to begin with although the engine did run in reverse only at one point. I measure 2 ohms between commutator sections an 20 ohms between the armature shaft and each section which is consistent with a working engine (wires not disconnected) so there are no apparent shorts.

Everything looks fine and it won't run. I must be missing something but I have no idea what.

 

The commutator segment to the armature shaft resistance reading is way to low. You indicated the reading was 20 ohms.  It should be in the hundreds of thousands of ohms. There is either a grounded armature coil or the insulation on the commutator has failed. What I would do is disconnect the leads from the three commutator lugs and retest checking the armature coils and commutator separately.  If the commutator resistance to ground is low, a new commutator can be installed.  Change the felt pad under the commutator at the same time. If it is the armature coil leads to the shaft that are low, the armature will need to be rewound. 

Before trying to pull the commutator off, I recommend that you have a spare on on hand. The commutator frequently breaks when being pulled off.  Before pulling the commutator, mark the positions of the slots on the rotor so when the new one goes on the timing will be correct. Both The Train Tender and Just Trains sell commutators.  Bob Hannon is a good place to get the armature rewound if that is required. 

20hms is far too much contact I'd also think. (that is "smoke element" ohms, and the motor winding wire is pretty thin and not quite ni-chrome😉)

Ànother culprit can be the com. plate shifting a couple of degrees on a shaft, changing the timing. 

Field coil is just an electromagnet. Weakening and or shifting of the fields strong point on a revolution can reveal issues sometimes. (compare the pull to another fields pull using your "keychain"or something else magnetic near it).

Also makes for fast auto alternator/generator test on the shoulder or in the pits. A functioning alt/gen. becomes magnetic if producing so keys swing towards it when running.

Getting hot real fast also notes a possible loss of wire length/short; by lowering (useful here) resistance, heat comes on very fast.

 

The Bob Hannon book is probably the "bible" on Postwar motor troubleshooting.  All of these measurements are in there.  [I often wonder how many motors he took apart, to come up with those normative values!]  Anyhow, it's an invaluable resource for this sort of thing.

I would be surprised though to learn that this is the cause.  I've messed with Postwar since my teens, and I've seldom come across a burned-out armature coil.  It's good to know that there are folks who rewind them.  But on many steam locos, removal and reinstallation is a pro-level repair.  Check the basics first!

Same engine 2037, took apart fixed heater element, replaced wire to heater, reassembled--no work.

Next day read this thread, took advice to put a known working locomotive on... nogo.

Found the short circuit where i put a metal 145 gateman right on the track at the other end of the layout aftet troubleshooting it...doh!

Saved me from more work, thank you.



Dan

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