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Discussion Boards => N => Topic started by: capt_langlois on September 06, 2008, 12:13:11 AM

Title: Backwards Traveling Engine
Post by: capt_langlois on September 06, 2008, 12:13:11 AM
I recently aquired two Bachmann F9 engines. I was hoping to run them together, but when I set them on the track, one engine went one direction and the other engine the other direction. I reversed the direction on the controller and now the two went at each other. I have no idea what is going on. As always I appreciate all the advice I can get, thanks for the help.
Title: Re: Backwards Traveling Engine
Post by: fieromike on September 06, 2008, 08:41:42 AM
Most likely, someone has had one (or both) of the engines apart and put the motor in upside down.  Just careully disassemble the 'wrong' engine, and flip the motor 180°, reassemble, and you should be in business.
Title: Re: Backwards Traveling Engine
Post by: capt_langlois on September 06, 2008, 01:11:07 PM
I opened the engine and tried to flip the motor 180 degrees but came up empty. The housing only allows for the motor to fit in the one direction. I am back to drawing board, so any help once again would be greatly appreciated.
Title: Re: Backwards Traveling Engine
Post by: fieromike on September 06, 2008, 10:13:31 PM
If we're both thinking of the same engine with a split frame and no wires to the motor, the problem HAS to be with the motor.  The motor could have been assembled wrong at the factory, or a previous owner might have completely disassembled the motor and got the magnets backward.  You might end up sending it back to Bachmann...
Title: Re: Backwards Traveling Engine
Post by: capt_langlois on September 07, 2008, 01:48:13 AM
Yeah that is what I am thinking. You described my engine exactly and there are no wires. I wish there was something I could do specifically but Im not sure. I dont have the warranty info since I bought the engine used so I dont think Bachman will help. Any suggestions now?
Title: Re: Backwards Traveling Engine
Post by: fieromike on September 07, 2008, 09:54:12 AM
Yep.  Call Bachmann service dept.  You'll pay repairs on an out-of-warranty engine.  As inexpensive as those engines are, it might be worth a bit of browsing through that auction site.
Title: Re: Backwards Traveling Engine
Post by: GlennW on September 07, 2008, 01:51:49 PM
If you can get to a swap meet, you could look for a LifeLike GP20. If you can get it cheap enough, swap the LL shell for the Bachmann.
Title: Re: Backwards Traveling Engine
Post by: capt_langlois on September 10, 2008, 12:44:39 PM
Quote from: fieromike on September 07, 2008, 09:54:12 AM
Yep.  Call Bachmann service dept.  You'll pay repairs on an out-of-warranty engine.  As inexpensive as those engines are, it might be worth a bit of browsing through that auction site.

You mentioned browsing through an auction site? I was wondering if buying a new motor for the engine and swaping it out for the old one would rectify the problem. If so, where can I buy one and how much would it set me back? Otherwise I was going to get creative and solder the engine contactors backwards in attempts to run the engine backwards but I would prefer an easier less time intensive solution.
Title: Re: Backwards Traveling Engine
Post by: David Leonard on September 10, 2008, 02:53:19 PM
Does this thing have axle pickup or wheel pickup? If one truck picks up current from one rail (via axle wipers) and the other truck from the other rail, you might be able to reverse the polarity by switching the wheel sets.
Title: Re: Backwards Traveling Engine
Post by: alhoop on September 10, 2008, 06:26:30 PM
I'm almost positive that the motor is symmetrical and should go in either way.

Title: Re: Backwards Traveling Engine
Post by: capt_langlois on September 11, 2008, 05:51:02 PM
I hate to tell you but the engine will positively only fit one direction. The metal casing in which the engine sits only allows for the motor to point one way. I can spin the motor allowing the contacts to connect the same way to the metal housing but the driveshaft exiting the motor is still facing the same way resulting in the backwards running (if that makes sense). This particular F9 has an electrical pickup throuh the wheels. Like you mentioned though, I did switch the two trucks around thinking the same thing however was unsuccessful. For such a simple problem, I sure am stumped. Thanks for all the imput thus far, I do appreciate your guys' experience.
Title: Re: Backwards Traveling Engine
Post by: taz-of-boyds on September 11, 2008, 07:47:20 PM
I believe the idea is to switch the motor contacts from the frame halves they contact now to the other frame halves, thus electrically reversing the motor, not turning the motor shaft around??
Charles
Title: Re: Backwards Traveling Engine
Post by: alhoop on September 12, 2008, 08:39:12 AM
I've owned several Bachmann f9s, both the old metal gear one and the plastic gear type. The motor could be mounted to make the engine run in opposite directions.
When you say one direction are you talking front to back?" Point one way" sounds like you are attempting to turn the motor front to back. As taz-of-boyds sez, the idea is to flip the motor so that  the brush cap that was on the bottom is now on top.
Let us know.
Title: Re: Backwards Traveling Engine
Post by: morrisf on September 16, 2008, 09:34:15 AM
I've got the same problem with the no. 81259 F7 A/B set.

One runs backwards and the motor can be neither repositioned nor rewired.

I'd like to view the solution to this problem, too.
Title: Re: Backwards Traveling Engine
Post by: alhoop on September 16, 2008, 02:08:39 PM
Quote from: morrisf on September 16, 2008, 09:34:15 AM
I've got the same problem with the no. 81259 F7 A/B set.

One runs backwards and the motor can be neither repositioned nor rewired.

I'd like to view the solution to this problem, too.

Morris:
Are you saying that you cannot rotate the motor 180 degrees on its axis so that the brush cap that was on the bottom is now on top?
Al
Title: Re: Backwards Traveling Engine
Post by: morrisf on September 17, 2008, 09:22:56 AM
Dear Al,


I just now took your advice and rotated the motor as you suggested.

The unit now runs in the correct direction.

Thanks for the solution!


Morris
Title: Re: Backwards Traveling Engine
Post by: TCWORLD on September 18, 2008, 06:37:02 PM
I know this might sound daft, but has the shell on one of them been put on back to front (i dont know wheter they can be put on eitherway around or not, so i thought id ask).
Title: Re: Backwards Traveling Engine
Post by: morrisf on September 20, 2008, 02:49:31 PM
On straight DC, all engines should run in the same direction when on the same track, no matter which way the shell is on, or if it even has a shell or not.


In other words...

The mechanisms must all go the same way (follow each other as in a parade) on the same polarity; otherwise, there's something wrong with the wiring or the motor windings/terminals.
Title: Re: Backwards Traveling Engine
Post by: TCWORLD on September 21, 2008, 12:15:17 PM
IVe just noticed that you managed to flip the motor, which is good im glad youve got it working, i hadnt seen that before i made my last post.

Just as a side note the suggestion i made was valid, as the result of doing what i said would have meant that one of the locos mechanism/chassis would be on the rails in the opposite direction to before if you put the train on the track with so that the shell faced the same way as before (effectively flipping the chassis around under the shell,)
Title: Re: Backwards Traveling Engine
Post by: James in FL on September 23, 2008, 07:45:16 PM
TC,

It's polarity.
It matters not which way the shell is mounted.
It matters not which way the chassis is turned on the track.

The only way to reverse the direction of travel is to reverse the polarity to the motor.

In this case, the only way to reverse the polarity was to rotate the motor 180 degrees, not front to back, but rather roll it over.

You could have reversed the chassis on the track and reversed the body too...
They still would not run in the same direction.

; )

edit for spell check
Title: Re: Backwards Traveling Engine
Post by: TCWORLD on September 24, 2008, 06:07:51 PM
I understand what you are saying, but im pretty sure what im saying is correct, so ok bare with me, lets ignore the shell, and ignore that there are two trains for one second, in fact lets ignor there is a train altogether.
If you take any DC motor and connect it to a track where say the left rail is + and the right rail is -. The motor will go for wards when its + is connected to the left rail. If the + of the motor was connected to the right it would go in reverse. Basic motors, im certain you know that.
Right then the chassis of the train is basically the connections of the motor to the track (if you ignore the gearing as that isnt important). Lets say that the motor 'cannot' be rotated in the chassis, and at the moment its + is connected to the right side of the chassis. It will go bacwards like i said above. Now, in order to make it go forward, there are 3 options:
1: rotate the motor 180' that method works if you can rotate the motor, but what if you cant (which was the purpose of my original suggestion).
2: you can reverse the polarity of the track, but if there are two engines with motors connected opposite ways around, you cant.
and finally 3: if the chassis has two sides A and B. A is connected to the left, and B the right. The motor is fixed to these so that its + is joined to B (the tracks -). If you rotate the whole chassis around 180' then side B is now on the left and A the right. We know that B is connected to the motors + and now it is connected to the left rain of the track (the tracks +).
oh, now the motor turns forwards, and the chassis goes in the same direction as the second engine. finally, re-add the shell to the chassis, only putting it on the opposite way around to the way it was before. The locos go in the same directions when they are both pointing forwards in terms of how which way the shell is pointing not the chassis's.

Im sorrry that i went on for a bit then, but correct me if im wron about what ive just said (which an explanation to my suggestion earlier). If you think im wrong, I will go and recreate the problem with some locos and see if the solution works.
Thanks Tom.
(p.s. I know which the best method is which was the flipping of the motor, but i was just sharing an idea if it hadnt been possible to flip the motor)
Title: Re: Backwards Traveling Engine
Post by: taz-of-boyds on September 24, 2008, 07:44:19 PM
Sounds like there ain't no way.  As the other guys have posted:  as you turn the chassis around you end up with a double negative; 1, the gearing in the chassis is reversed, and 2, the polarity of the motor is reversed.  You noted the change in motor polarity, but did not realize the reversing of the gearing counts too.  The locomotive still runs opposite of the other locomotive.  So unlike my linguistic double negative, the two negatives on the loco do not accomplish the intended goal.  The motor leads need to change chassis-electrical pickup sides.  Or something like that...
Charles
Title: Re: Backwards Traveling Engine
Post by: TCWORLD on September 25, 2008, 01:08:41 PM
Quote from: taz-of-boyds on September 24, 2008, 07:44:19 PM
the gearing in the chassis is reversed
Good point. I have to admit i completely forgot to take into account the gearing :doh:
you are completely correct, now tats cleared up, im going to slowly back away and hide in a corner until everyone forgets i've just made a completly basic mistake  ;D