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American Flyer Steam Engine - Runs Too Slow

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American Flyer Steam Engine - Runs Too Slow
Posted by richhotrain on Thursday, November 18, 2010 12:41 PM

I am quickly getting fed up with the performance of my American Flyer steam engine.  It is a #312, 4-6-2 engine.

I recently replaced the smoke wick and coil and that is now the best thing about it.  Smokes up a storm.

However, in spite of cleaning up the vintage open-frame motor, lubricating the gears, and even oiling the driver wheel linkages, it runs slow.  In fact, it ran faster with the boiler shell off and just the smoke unit and motor were sitting on the wheel assembly.  If I add cars behind the engine and tender, it runs even slower.

I power the tracks with my old vintage American Flyer 8B, 100 watt, transformer.  Voltage around the layout is a continuous 15.4 volts, dropping to 14.9 volts as the engine crossing the rails where the voltage meter probes are set.

I could purchase a reconditioned American Flyer 30B transformer which puts out 18 volts to beef up the speed, but I am not sure if it is the transformer, the motor, or the electrical pick up.

Any thoughts or ideas?

Rich

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Posted by Anonymous on Thursday, November 18, 2010 4:18 PM

Rich,

           Sounds like bad brushes and springs to me.  The 314AW that I am working ran slow after cleaning and lube, and the cause was that the brush springs were weak.  I replaced them, and it runs faster now.

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Posted by richhotrain on Thursday, November 18, 2010 6:17 PM

green97probe

Rich,

           Sounds like bad brushes and springs to me.  The 314AW that I am working ran slow after cleaning and lube, and the cause was that the brush springs were weak.  I replaced them, and it runs faster now.

Jim,

Great to hear that.  I wondered about the brushes and springs.  After all, they are 62 years old.

Anybody care to disagree with that line of reasoning before I place my order for replacement parts?

Rich

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Posted by hectorgonzales on Thursday, November 18, 2010 10:48 PM

I disagree. Don't waste your money. I've got a #342 and I've replaced the springs,brushes and even swapped out armatures with another engine. I cleaned and lubricated all the gears. It still runs agonizingly SLOW. It barely pulls 3 cars.

My solution? I still run it, but I bought a brand new Lionel S scale shown below. It runs FAST smooth and quiet. It doesn't look as cool, but at least its reliable.

 

Here's my 342

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Posted by Major on Friday, November 19, 2010 7:10 AM

Brushes and springs are cheap and I always suggest replacing them.  However also look at the fingers on the reverse unit.  Make sure they are not worn and barely making contact on the drum.  Clean the drum! The motor is running slow because insufficient current is getting to it. And when it is under load it demands more juice!  You may have a bad connection on the leads from the tender trucks.  While the wire may still be attached most of the strands are broken restricting current flow.  If you can switch tenders and if the loco runs fine you have ruled out the motor being a problem.   Another area to look at is the wires leading from the tender to the plug.  I have encountered the fabric being stuck  but the majority of the strands in the wires being broken.  This will definatlely prevent you engine from pulling!    I hope this helps.

Rich.

 

 

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Posted by richhotrain on Friday, November 19, 2010 7:27 AM

hectorgonzales

I disagree. Don't waste your money. I've got a #342 and I've replaced the springs,brushes and even swapped out armatures with another engine. I cleaned and lubricated all the gears. It still runs agonizingly SLOW. It barely pulls 3 cars.

Nooooooo !

I raised that challenge rhetorically. I never expected anyone to disagree.

So, now it is one in favor of replacing the brushes and springs, one against.

Anyone else?

Rich

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Posted by richhotrain on Friday, November 19, 2010 7:39 AM

Major

Brushes and springs are cheap and I always suggest replacing them.  However also look at the fingers on the reverse unit.  Make sure they are not worn and barely making contact on the drum.  Clean the drum! The motor is running slow because insufficient current is getting to it. And when it is under load it demands more juice!  You may have a bad connection on the leads from the tender trucks.  While the wire may still be attached most of the strands are broken restricting current flow.  If you can switch tenders and if the loco runs fine you have ruled out the motor being a problem.   Another area to look at is the wires leading from the tender to the plug.  I have encountered the fabric being stuck  but the majority of the strands in the wires being broken.  This will definatlely prevent you engine from pulling!    I hope this helps.

Rich.

 

Oooh, 2 to 1 in favor of replacing the brushes and springs.

Major, you raise a good point on the wires from the tender.  When I was in the process of rehabbing my old steamer last January, I had cut the original braided wires from the tender to the jack panel on the back of the engine.  So, I ordered a new wiring harness from a well known source, whose name I will not mention.  Three months later when the wiring harness arrived in the mail, it was hardly a reproduction of the original AF wiring harness.  Instead, it looked like four different colored Brawa 26 gauge wires wrapped in a shoelace.  I wired it in but ever since the speed of the engine has been considerably slower, coincidence or otherwise.  I have wondered if the electrical pick up is good from the rails to the tender but if the electrical current is reduced to the motor because of inadequately sized wiring in the harness.  Now that  the issue has been raised, I will check that out with a volt meter.

Rich

Edit Note:  If I place the tender on the track with tender side of the jack plug disconnected from the engine (i.e. the male plugs), can I just place the probes from my volt meter on the outside two jack plugs or do I also jumper together the inside two plugs.  I don't seem to be getting readings when I merely touch the two probes to the outside two jack plugs with the transformer set to maximum speed.

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Posted by Major on Friday, November 19, 2010 12:52 PM

It sounds like that would be a good place to start.  Not being a purist when I have rewired the connection from the tender to the plug I just use black stranded wire.  It is flexible enough and that solved my connection problem. I own three 312 pacifics and they are some of my best, smoothest quietest runners. On one of them I completely removed the plug connection and direct wired the motor to the tender in the same fashion that Gilbert did in the mid 50s on later steam locomotives.  It is one less thing that can go wrong.

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Posted by lionelsoni on Friday, November 19, 2010 1:56 PM

Measuring voltage without the tender unplugged from the locomotive will not tell you anything about the voltage drop that might be occurring when the train is running.  That voltage drop is equal to the wire resistance multiplied by the current.  If the current is zero, so is the voltage drop.

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Posted by richhotrain on Friday, November 19, 2010 5:45 PM

lionelsoni

Measuring voltage without the tender unplugged from the locomotive will not tell you anything about the voltage drop that might be occurring when the train is running.  That voltage drop is equal to the wire resistance multiplied by the current.  If the current is zero, so is the voltage drop.

Is there any way to measure the amount of voltage reaching the motor?

Rich

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Posted by lionelsoni on Friday, November 19, 2010 6:54 PM

Not easily.  You would have to measure the armature and field voltages separately, because they are both supplied separately from the tender.  To make these measurements meaningful, you would have to have to locomotive loaded as it is when pulling a train.  Unless you have a dynamometer track, that means having a voltmeter in the train, which would be quite a trick to read, or a telemetry arrangement to get the readings from the moving train to you.

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Posted by SkyArcher on Friday, November 19, 2010 6:58 PM

How do you test the field coil and armature wiring ti be sure that they're not shorting

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Posted by richhotrain on Friday, November 19, 2010 7:07 PM

lionelsoni

Not easily.  You would have to measure the armature and field voltages separately, because they are both supplied separately from the tender.  To make these measurements meaningful, you would have to have to locomotive loaded as it is when pulling a train.  Unless you have a dynamometer track, that means having a voltmeter in the train, which would be quite a trick to read, or a telemetry arrangement to get the readings from the moving train to you.

Bob,

Thanks for that info. 

Since measuring voltage at the motor would be difficult, if not down right impossible, let me ask this question.  Since the gauge of the wires in the wiring harness may be too small to carry adequate voltage to the motor, is there a general rule of thumb that can be applied regarding the minimum gauge wire to ensure that adequate voltage is being supplied to the motor?

Rich

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Posted by hectorgonzales on Friday, November 19, 2010 8:10 PM

Major

It sounds like that would be a good place to start.  Not being a purist when I have rewired the connection from the tender to the plug I just use black stranded wire.  It is flexible enough and that solved my connection problem. I own three 312 pacifics and they are some of my best, smoothest quietest runners. On one of them I completely removed the plug connection and direct wired the motor to the tender in the same fashion that Gilbert did in the mid 50s on later steam locomotives.  It is one less thing that can go wrong.

I did the same thing and highly recommend it. I guess I shouldn't have been so blunt. Yes, I think you should still replace the brushes and springs. It's not a bad idea. Just don't expect a dramatic change. The only thing I haven't done is replace the coil. The armature was used, so maybe I should have purchased new? I dunno. I've had the engine apart about a dozen times, and rewired it with little effect. I mean at least it runs OK, just not real fast and cannot pull more than a few cars.

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Posted by lionelsoni on Friday, November 19, 2010 8:22 PM

Almost any wire heavy enough to be mechanically robust would be big enough.  Here is my reasoning:

I assume that 100 millivolts is a tolerable voltage drop and that a typical Flyer locomotive draws about 2 amperes.  This gives us a maximum resistance of  50 milliohms.  Assuming that there is about 2 feet of wire involved in the entire circuit, that is 4 wires each 6 inches long, this requires a maximum resistivity of 25 milliohms per foot, which corresponds to about 24 AWG.  (Resistance doubles about every 3 gauge numbers and increases by a factor of 10 about every 10 gauge numbers.  Ten AWG has a resistance of 1 milliohm per foot.)

Bob Nelson

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Posted by richhotrain on Saturday, November 20, 2010 6:43 AM

lionelsoni

Almost any wire heavy enough to be mechanically robust would be big enough.  Here is my reasoning:

I assume that 100 millivolts is a tolerable voltage drop and that a typical Flyer locomotive draws about 2 amperes.  This gives us a maximum resistance of  50 milliohms.  Assuming that there is about 2 feet of wire involved in the entire circuit, that is 4 wires each 6 inches long, this requires a maximum resistivity of 25 milliohms per foot, which corresponds to about 24 AWG.  (Resistance doubles about every 3 gauge numbers and increases by a factor of 10 about every 10 gauge numbers.  Ten AWG has a resistance of 1 milliohm per foot.)

Thanks again, Bob.

My guess is the wiring harness that I wound up getting is somwhere between 24 AWG and 28 AWG.  That sounds barely acceptable.  Of course, four wires in a wiring harness at 10 AWG each would be way too thick and rigid for an S scale engine and tender connection, as would 12 AWG to 16 AWG.  So, my assumption is that the ideal gauge for this purpose would be somewhere between 18 AWG and 22 AWG.

I wonder what the original AC Gilbert supplied wiring harness wires were sized.  Anyone know?

Rich

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Posted by Anonymous on Sunday, November 21, 2010 6:05 PM

Rich,

          Original harnesses are around 24AWG.  I've never had any issues with reproduction harnesses.

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