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 Posted - July 14 2009 : 8:01:55 PM
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I have 2 DC HO U33B's, (twin flywheels etc)
Setting the cab at 1 level & leaving it alone, the older gray motor version runs smoothly over my track , which has voltage variations within the blocks, without showing signs of being affected by them.
With the Cab set at the same setting, the more recent can motor version is very sensitive & speeds up & slows down of its own accord. Presumably in response to the voltage it is receiving. I have checked brushes, cleaned the commutator & wheels & strip contacts that sit over the motor & trucks. Also pulled it down & lubricated the Gbox & diffs & motor & still no difference in its performance.
What I am wondering is what are the key determinants that could make 1 U33B run steadily over a track & another speed up & slow down over the same track?? .
Could it be a faulty motor or truck pick ups ??
Thanks
Tanked
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Posted - July 14 2009 : 9:17:30 PM
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I'll add a bit more to the jigsaw puzzle.
Running the 2 U33B's hooked together it is quite noticeable that the steady one has a stronger 'headlight' bulb & where the erratic one slows them down its bulb can flicker, suggesting erratic pickup??, whereas the other one's bulb stays steady.
I think both have sat in boxes for a few years, the erratic runner had surface rust on the power strips that I cleaned up.
Some questions:
Brushes - can they go 'stale'??
Truck pick up - They both have those power trucks with the strip of metal sticking up then bent over at a right angle - where does it pick up the power from before it passes it on to the powerstrips that radiate out back & front from the top of the motor?
What problems can there be with this power pick up system [apart from misalignment of the truck strip with the power strips where they touch]?
Thanks
Tanked
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Posted - July 15 2009 : 12:54:38 AM
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I'll try to give you some help.
1 No, brushes don't go "stale" over time. They can be ruined by oil contamination though. But I don't think that would cause the problems you have. Try switching the brushes between the motors and see if that changes anything.
2 Remove a truck and look at it from the rear. The bent metal strip runs down to one side of the truck. It collects power from the wheels on that side. You will see another metal strip with a hole in it where the frame mounts to the truck. That strip takes power from the wheels on the other side of the truck and passes it to the frame.
3 Problems? Potentially lots! But main ones are:
dirt on wheels
dirt/oil in wheel bearing surfaces
dirt/oil/rust at contact point with frame
Dirt/oil/rust at contact points with upper power contact
By "can motor", are you refering to the golden colored motor with brass flys?
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Posted - July 15 2009 : 10:31:22 AM
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quote:I'll try to give you some help.
2 Remove a truck and look at it from the rear. The bent metal strip runs down to one side of the truck. It collects power from the wheels on that side. You will see another metal strip with a hole in it where the frame mounts to the truck. That strip takes power from the wheels on the other side of the truck and passes it to the frame.
3 Problems? Potentially lots! But main ones are:
dirt on wheels
dirt/oil in wheel bearing surfaces
dirt/oil/rust at contact point with frame
Dirt/oil/rust at contact points with upper power contact
By "can motor", are you refering to the golden colored motor with brass flys?
Originally posted by Hypoponera-July 15 2009: 12:54:38 AM
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Thanks H
I have an old F7 truck in front of me & can now spot what you are writing about. I hadn't till now noticed the subtleties of the metal contact system in the trucks.
Bear with me re the following:
Am I correct in guessing the power flow is rail to wheel to axle to brass bearing to metal finger structure sitting over the bearing to horizontal metal strip above motor, to motor. & the other side of the flow is as above, except it runs into the chassis and then the bottom of the motor, ilo the metal finger arrangement?
I presume to get the trucks/axles apart one flicks the plate on the underside of the truck & goes from there?
Can motor - it has brass flys, but the can case is more 'silver' colored than gold. Not sure if its 'faded ' gold or was always dull 'silver'.
Tanked
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Posted - July 16 2009 : 10:56:44 AM
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You are essentially correct regarding the electric flow.
Before you tear down a truck, I suggest you have a copy of the directions in front of you. You can get them at HOseekers site. You will need to have the directions for the correct production run of your truck. Chances are that the trucks that go to the older, gray motor are of the old type with metal truck side frames. The trucks with the newer motor probably have plastic side frames. Those two trucks are slightly different.
There was a very good site for tuning-up Athearn trucks. Seems the site is gone though. Maybe you can get a link to the thread that Ray mentioned in another thread of yours?
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Posted - July 16 2009 : 12:20:05 PM
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Here is a link to the how to I did.
http://www.2guyzandsumtrains.com/Content/pa=showpage/pid=24.html
Does the older one have the metal side frames?
The newer ones with the plastic side frames and inside (square) bearings don't conduct current as well as the older ones if the metal bearing carriers has rust on them.
Ray
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Posted - July 16 2009 : 1:48:39 PM
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quote:Here is a link to the how to I did.
http://www.2guyzandsumtrains.com/Content/pa=showpage/pid=24.html
Does the older one have the metal side frames?
The newer ones with the plastic side frames and inside (square) bearings don't conduct current as well as the older ones if the metal bearing carriers has rust on them.
Originally posted by Ray Marinaccio-July 16 2009: 12:20:05 PM
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Ray
I think the older does have metal side frames.
Will check metal bearing carriers on the new one.
The 'How To' tune up article is very useful.
Thanks
Tanked
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Posted - July 16 2009 : 5:04:08 PM
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| By the way, the newer silver/golden motor is far more responsive then that old, gray motor. Maybe that responsiveness is the cause of your problems? It is reacting to the slight current variations of your track while the older motor just doesn't notice the difference.
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Posted - July 17 2009 : 11:43:55 PM
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quote:By the way, the newer silver/golden motor is far more responsive then that old, gray motor. Maybe that responsiveness is the cause of your problems? It is reacting to the slight current variations of your track while the older motor just doesn't notice the difference.
Originally posted by Hypoponera-July 16 2009: 5:04:08 PM
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The newer motor - I took apart the trucks per Ray's 'How To', washed everything, sanded off some surface rust & reassembled & lubed it all.
Also polished the armature a bit & changed the motor brushes.
What I have now is a unit that runs a lot smoother now but is pulling a lot more current than the older U33B.
For example, the Cab has 0 to 100 dial scale. The older U33B starts moving at '30' setting, whereas the newer needs a cab setting of '60' to get going.
The upshot is that after 1/2 an hours slow running at '70', the newer U33B's motor was hot as were the flywheels- I suspect its not meant to get that hot.
I am wondering what could be causing this??
Tanked
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Posted - July 18 2009 : 02:17:48 AM
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ray, that's a good write up you did on the athearn truck & motor. i like how you hard wired the upper & lower clips. i was pondering just that myself earlier today.
jerry
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Posted - July 18 2009 : 08:17:28 AM
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quote:[quote]
The upshot is that after 1/2 an hours slow running at '70', the newer U33B's motor was hot as were the flywheels- I suspect its not meant to get that hot.
I am wondering what could be causing this??
Originally posted by TankedEngine-July 17 2009: 11:43:55 PM
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Something that may be relevant - although I lubed the truck gears, I did not lube the axles, so they will be dry & may be causing drag in the trucks?? Not sure if should lube where the axles run through the 'square brass' bearing blocks or not due to the conductivity issues.
Any thoughts??
Tanked
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Posted - July 18 2009 : 3:39:30 PM
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quote:
What I have now is a unit that runs a lot smoother now but is pulling a lot more current than the older U33B.
For example, the Cab has 0 to 100 dial scale. The older U33B starts moving at '30' setting, whereas the newer needs a cab setting of '60' to get going.
The upshot is that after 1/2 an hours slow running at '70', the newer U33B's motor was hot as were the flywheels- I suspect its not meant to get that hot.
I am wondering what could be causing this??
Tanked
Originally posted by TankedEngine-July 17 2009: 11:43:55 PM
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Boy, is that backwards. The gold motor should be drawing less than the old Jet 600. It sounds to me like you've got a set of weak magnets in the newer motor, which will cause overheating and high current draw. This could have happened due to a strong shock (i.e. the motor was dropped), or overheating, which we saw happen to Athearns at Northlandz. I don't think these ceramic magnets lose any strength if the armature is removed from the field, like older open frame motors will.
I think it's new motor time.
The Tyco Depot
Edited by - NickelPlate759 on July 18 2009 3:40:19 PM
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Posted - July 18 2009 : 9:50:35 PM
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quote:quote:
What I have now is a unit that runs a lot smoother now but is pulling a lot more current than the older U33B.
For example, the Cab has 0 to 100 dial scale. The older U33B starts moving at '30' setting, whereas the newer needs a cab setting of '60' to get going.
The upshot is that after 1/2 an hours slow running at '70', the newer U33B's motor was hot as were the flywheels- I suspect its not meant to get that hot.
I am wondering what could be causing this??
Tanked
Originally posted by TankedEngine-July 17 2009: 11:43:55 PM
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Boy, is that backwards. The gold motor should be drawing less than the old Jet 600. It sounds to me like you've got a set of weak magnets in the newer motor, which will cause overheating and high current draw. This could have happened due to a strong shock (i.e. the motor was dropped), or overheating, which we saw happen to Athearns at Northlandz. I don't think these ceramic magnets lose any strength if the armature is removed from the field, like older open frame motors will.
I think it's new motor time.
Originally posted by NickelPlate759-July 18 2009: 3:39:30 PM
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Well I did have a new motor in the corner & dropped it in today - but only a slight improvement resulted.
However, I suddenly realized that the motor mounts I took off the previous motor & was using were sloppy & in an 'aha' moment duct taped the new motor down tight to the chassis - and now the setup is running better than the older gray motor U33B.
Next thing is to get new motor mounts & try the previous motor.
Looks like the problem was poor contact between the bottom of the motor electrical pickup & the chassis contact strip due to loose engine mounts.
Tanked
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