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Loco Runs the Opposite Direction

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Loco Runs the Opposite Direction
Posted by Regg05 on Tuesday, June 18, 2013 8:44 AM

Hey,

I bought a used GW GP20 off of Ebay a couple of months ago for a fairly decent price.  What I've noticed however was that it runs the opposite direction of all the other locos.  My layout is DC.  So if the power pack is set on foward the loco runs in reverse and when in reverse it runs forward.  It can be a bit of an annoyance because right now I got a double main line and running both lines off one powerpack.  So my intentions my be to run one train one direction and the other main line the other direction but if i want to sue this engine it runs the same way as the other engine.  What could this be???

Thanks,

Quan

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Posted by cacole on Tuesday, June 18, 2013 8:58 AM

Remove the shell and reverse the wires to the motor.  The seller probably reversed the wiring to the motor so it could be ran backwards as the second unit in a consist.

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Posted by soilwork on Tuesday, June 18, 2013 9:01 AM

If it's dcc ready locomotive, just try flipping the plug on the harness.

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Posted by cowman on Tuesday, June 18, 2013 6:54 PM

Years ago my sons Bachmann did that right out of the box.  I wasn't into doing much in the way of repairing or changing then (still reluctant), but it does happen right from the factory.  If you only have one loco, you never notice.

I'd say reversing the wires should help.

In DC it made no difference which way you put the loco on the track, they go the same direction (most of them), all you had to do was turn the loco around to have it run with the other hood forward.

Good luck,

Richard

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Posted by richhotrain on Wednesday, June 19, 2013 4:45 AM

All performance issues should be so simple.

Someone reversed the two motor wires.

Reverse them back to the proper postion.

Cacole is probably right.

Rich

Alton Junction

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Posted by BRAKIE on Wednesday, June 19, 2013 6:17 AM

David,Cacole is spot on..

I've bought several used Athearn engines years ago and all was "wired to mu together in the proper direction" so sayth the seller with pride. I held my laughter. It was a simple matter of  flipping the trucks around to fix the problem..

 

Larry

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Posted by nedthomas on Wednesday, June 19, 2013 6:40 AM

What brand is the loco? Depending on the electrical pick-up in the trucks maybe  the wheelsets got reversed somehow.

I said wheelsets, no the whole truck. If the wheelset was removed for cleaning etc they have been re-installed wrong.

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Posted by zstripe on Wednesday, June 19, 2013 6:46 AM

Larry,

You're not serious are you?? About flipping the trucks around?

Cheers,

Frank

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Posted by zstripe on Wednesday, June 19, 2013 6:50 AM

The simplest, and easiest,just switch the motor leads...

Cheers,

Frank

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Posted by rrinker on Wednesday, June 19, 2013 6:59 AM

 The way Athearn BB locos work, yes, flipping the front and rear trucks actually does change which rail pickup goes to which motor lead. Since there are no wires, this is actually super easy to do. On a clone type loco that has repalced the top clip with wieres, it wouldn;t be as easy, easier to just change the wires.

 Think about it - if the right side of the truck is the red wire with the loco facing forward, to swap the trucks you need to rotate them 180 degrees. So now the red wire would be on the left side of the loco. On a loco that uses wires from the trucks to motors, generally you'd have to disconnect the wires to do this, so yes, easier to just change which wire goes where. On the Athearns with no wires, that is pretty much the ONLY way you can do it, since there are no wires to switch. Just pop off the top clip on each truck that holds the worm (don't lose the bearings!) and the trucks unsnap, flip around and reassemble.

 

           --Randy

 

zstripe

Larry,

You're not serious are you?? About flipping the trucks around?

Cheers,

Frank


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Posted by BroadwayLion on Wednesday, June 19, 2013 7:02 AM

LION SAYS... Left rail is (-) and Right rail is (+), locomotive will move in correct direction.

In DC operation, only the track polarity controls the direction of the locomotive no matter which end has the little "F" painted on it. Your reversing switch is not FWD and REV, but rather EAST and WEST, and it cares not which end of the locomotive is pointed in which direction.

LION does not even have reversing switch on his layout. Subway trains NEVER run backwards.

ROAR

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Posted by zstripe on Wednesday, June 19, 2013 7:19 AM

Randy,

I understand that perfectly well,,,,,,but I'm sure it is a lot easier to just reverse,the wires,,

Cheers,

Frank

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Posted by BRAKIE on Wednesday, June 19, 2013 7:19 AM

zstripe

The simplest, and easiest,just switch the motor leads...

Cheers,

Frank

To change motor "leads" on a Athearn BB engine you would need to disassemble the drive and rotate the motor 180 degrees since the frame is the ground.. Simplest way is to turn the trucks 180 degrees.

 

If the BB engine had the metal strip replace with wire then,yes,reversing the wires would be the best way.

However,in this case the previous owner reverse the trucks to get the locomotives to "mu in the proper direction".

Larry

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Posted by zstripe on Wednesday, June 19, 2013 7:26 AM

If you rotated the trucks 180 degrees,,,how would you connect the drive line?

Cheers,

Frank

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Posted by zstripe on Wednesday, June 19, 2013 7:30 AM

Larry,

Now your last sentence,Makes all the sense in the world,,,,disregard,what I asked you..

Cheers,

Frank

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Posted by Mark R. on Wednesday, June 19, 2013 11:27 AM

zstripe

If you rotated the trucks 180 degrees,,,how would you connect the drive line?

Cheers,

Frank

Put the front truck on the rear and the rear truck on the front - turn each truck 180 degrees and put them on the opposite end.

Mark.

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Posted by Mark R. on Wednesday, June 19, 2013 11:39 AM

In a DC engine, provided they are all wired correctly, you don't have to change ANYTHING to mu any number of engine in any configuration. 

Place ten DC engines on the track and turn on the throttle, they all move to the right. Turn half of them around, turn on the throttle they all STILL move to the right !

If any of them don't, then it's wired backwards. The only way to fix it on an Athearn blue box is to swap the trucks front to back. You can't turn the motor around as it only fits one way. Any other engine where the motor is wired to a board, the two wires to the motor need to be reversed.

Mark. 

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Posted by zstripe on Wednesday, June 19, 2013 12:31 PM

Thank You,Mark,

I think after running them since 1952,,,,,I believe I think, I know what makes them tick..

Cheers,

Frank

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Posted by BRAKIE on Wednesday, June 19, 2013 1:45 PM

Mark R.

You can't turn the motor around as it only fits one way. Any other engine where the motor is wired to a board, the two wires to the motor need to be reversed.

Mark. 

 

Mark,Try turning the motor around..It will fit..More lessons learned the hard way.

Larry

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Posted by Mark R. on Wednesday, June 19, 2013 2:17 PM

BRAKIE

Mark R.

You can't turn the motor around as it only fits one way. Any other engine where the motor is wired to a board, the two wires to the motor need to be reversed.

Mark. 

 

Mark,Try turning the motor around..It will fit..More lessons learned the hard way.

I just looked at a couple of the few I have left .... there's four holes for the plastic motor mounts to press in to, with a rectangular recess towards the front and towards the rear from these holes. The one towards the front is longer than the rear so the motor will only go in one way.

The mounting pads aren't centered on the over-all motor .... even if you could turn it around, the drive shafts wouldn't fit.

Here's a GP35 frame - there's no way you could turn the motor 180 degrees and expect it to go in ....

 

Mark.

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Posted by zstripe on Wednesday, June 19, 2013 2:35 PM

Even if you could change the motor around,,,,,you will have the same problem,,,the polarity has to be changed,for the motor to turn in the other direction.. They pick up from the bottom and top of the motor..

Cheers,

Frank

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Posted by Mark R. on Wednesday, June 19, 2013 2:42 PM

zstripe

Even if you could change the motor around,,,,,you will have the same problem,,,the polarity has to be changed,for the motor to turn in the other direction.. They pick up from the bottom and top of the motor..

Cheers,

Frank

Actually it would .... if you could. The mount is designed like this so they all go in the same so they will all turn the same direction.

Think about it .... looking at the top of the motor, both shafts are turning away from you. Rotate the motor 180 degrees (without changing polarity) and now both shafts are turning towards you.

Have we all been away from DC THAT long ?  Laugh

 

Mark.

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Posted by Mark R. on Wednesday, June 19, 2013 2:47 PM

Everybody's now heading out to the shop to play with some Athearn DC chassis ! ....  Smile, Wink & Grin

Mark.

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Posted by zstripe on Wednesday, June 19, 2013 3:00 PM

Mark,

This has become interesting,,,there are two shafts connected to a armature,which is basically one shaft,,that is turning away from you,turning the motor around it will still turn the same way,,Direct Current flows one way,,,so turning the motor will not change any thing unless the Direct current is reversed.And if the pick up on the bottom or top is not changed it will still be the same..

Have Fun,

Cheers,

Frank

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Posted by Mark R. on Wednesday, June 19, 2013 3:07 PM

LMAO ! .... It's a physical thing Frank, not an electrical thing ! Go do it.

Hold a running motor in your hand with the shafts to the left and right, both shafts are turning away from you. Now turn the motor 180 degrees, the shaft are now turning towards you.

This is why the Athearn chassis are designed so the motor can only be installed one way at the factory so they know the motor will be turning the proper direction.

 

Mark. 

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Posted by zstripe on Wednesday, June 19, 2013 3:26 PM

Mark,

I agree,it is a physical thing,,,,but the motor is still turning in the same direction,,electrically,,,LOL..

Cheers,

Frank

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Posted by Mark R. on Wednesday, June 19, 2013 3:30 PM

zstripe

Mark,

I agree,it is a physical thing,,,,but the motor is still turning in the same direction,,electrically,,,LOL..

Cheers,

Frank

So now you agree that by turning the motor (physically) 180 degrees, the engine WILL run in the opposite direction even though the motor is still wired (electrically) the same ?

 

Mark.

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Posted by zstripe on Wednesday, June 19, 2013 3:35 PM

Mark,

No,,did I say that,,,,,must have been someone else,,,Just kidding,,, still think it easier to turn the trucks around,,than the motor,,,,LOL.

Cheers,

Frank

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Posted by Mark R. on Wednesday, June 19, 2013 3:52 PM

zstripe

Mark,

No,,did I say that,,,,,must have been someone else,,,Just kidding,,, still think it easier to turn the trucks around,,than the motor,,,,LOL.

Cheers,

Frank

Yes, it is easier to swap the trucks, because you CAN'T turn the motor. But trust me, IF you could turn the motor, the engine WOULD run in the opposite direction.

It's actually no different than physically picking up the engine and turning it 180 degrees - it will still be heading in the same direction on the track, but the engine itself will have visually changed direction (long hood vs. short hood)

Instead of dis-agreeing with me, just go try it ....

 

Mark.

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Posted by zstripe on Wednesday, June 19, 2013 3:58 PM

Mark,

I'm not disagreeing with you,,, I agree,I agree,,,,Wonder what the OP,thinks of all this??

Cheers,

Frank

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