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Bachmann K-27 New Gear Head Motor

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  • Mudhenbill
    replied
    Received the voltage regulators today, best deal on Ebay! Hooked it up to the 22.5 volt battery and placed it all in a gondola for testing. The extra volts did the trick and the engine runs smooth with no convulsing as before. It makes it around my sharpest 9 foot curve with no slow down either. I will have a video shortly after it loads.

    Video didn't take and its too hot outside, will do later. Off to another project!

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  • Mudhenbill
    replied
    Thank you, It's an Honor! I can hardly wait.

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  • Ray Dunakin
    replied
    BTW, congrats on the impending promotion to Grandpa!

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  • Mudhenbill
    replied
    Ok, Loco back together and a test was preformed, Much better but still not getting the results I want however, I think I am on the right track, forgive the pun. The top speed is good but still slowing way down on the 4% grade even with the cruse control. My guess is it needs more power than the 14 volts I currently have. I was fortunate to have a friend that gave me a 22.5 volt battery. I will be trying that option using a voltage regulator. I will experiment with 18 volts and then 22 volts and report back. If it works, I will post a video. Stay tuned.

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  • Mudhenbill
    replied
    Thanks, Tomorrow I'll put it all back together and give it the true test. Ill do another video.

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  • Ray Dunakin
    replied
    Nice work, and very interesting! Looks like it runs very smoothly, and the motor noise is definitely not excessive.

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  • Mudhenbill
    replied
    Video showing new motor, speed much improved

    https://youtu.be/KanEF0ut5To

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  • Mudhenbill
    replied
    Ok done with version 1.0. But not good enough. The speed on the layout is fine if you like really slow prototypical speed however, it is a garden railroad so it would be nice to have more speed when needed.

    I couldn't get the original number of 2.5333:1 out of my mind at the beginning of the post. There must be a way to use the existing gears and parts I have to make this happen. May I introduce version 2.0. After looking at the extra motors and gears I came up with a plan to utilize one motor gear with one of the extra gears giving me roughly 2:1. The big problem was the size of the out put shaft and having to turn it down again didn't excite me. since the original motor was garbage now, I decided to take it apart and use the shaft (good side), and incorporate it in the motor. After breaking off the armature I was able to use the shaft. I drilled out the gear to fit tight, placed it on the shaft and then started drilling and grinding to make the new shaft and gear fit. The original motor had an abundance of Bearings and trust washers of which I used to get the proper tension. Here are some pictures.

    Motor with gears removed except main drive gear



    This is the new shaft and gear in a new hole on the top piece







    Started with using nuts as temporary spacers, however found I will be using these permantly. I will have to fabricate a cover or just leave it.

    Everything all installed except the worm gear. Not pretty but it works.






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  • Mudhenbill
    replied
    Another update, I pulled a 20volt battery from a Bosch Drill and hooked it up on the bench, perfect high speed. I think I will be going with a 21.5 volt battery. MORE POWER!!! ARG! ARG!

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  • Mudhenbill
    replied
    Good news! I'm going to be a Grandpa 2x over!! Oh yah and the motor noise has dropped to almost nothing after a short hour break in..I think I'm more happy about the Grandpa experience, 2 more future model railroaders!

    Tomorrow I'll do a test run on the layout and see if it is going to pull anything up my grade. I can hardly wait. Just call me. Grandpa Mudhenbill!

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  • Mudhenbill
    replied
    Here is the YouTube link showing it working. You may think it is noisy however the boiler is not on and with the sound the generator has a very similar pitch. far less noise than the other gear box.

    https://youtu.be/aPmBGgBwNX8

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  • Mudhenbill
    replied
    Hummm Where to start?



    In order for the motor to fit in the cradle, one side needs to be cut off. I cut at an angle just at the mold line.



    I then reinstalled the cradle and then the motor. Once I did that I took the cut piece and welded it with super glue back to the cradle next to the motor and on the edge just like the opposite side.




    Next the gear box strap and a fabricated motor strap out of styrene.



    Ready for a test run.

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  • Mudhenbill
    replied
    Here is an update on the removing the gears. I have figured out that it is now a 5.9:1 ratio. With that info as well as the correct RPM's for this motor of 284 at 24VDC we can use the math above to figure the RPM's at the wheels.

    60 x 15:1= 900 This is the target RPMs of the motor.

    284 RPM's x 5.9:1 Gear ratio = 1675.60 RPM's This is how fast the motor runs at 24 volts.

    We then divide 1675.60 RPM's by 24 volts to get RPM's at one volt, 69.82 RPM's.

    To find out what RPM's at 14 we multiply,

    69.82 RPM's x 14 volts = 977.48 Motor RPM's!!!!!

    Walla!!! Roughly 60+ RPM's of wheel rotation.

    Conclusion, It is possible to use an off the shelf gear head motor to re-gear and motor the Bachmann K-27.

    Now the fun part making it all fit.

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  • Mudhenbill
    replied
    Ok, now that we have some good info at hand we can move forward, My experimenting would not have worked without it. As I mentioned above I had some motors that I had replaced on an Accucraft K-27. The original motor of 19:7.1 as well as my first attempt to make that engine run better with a 65:5.1. This was before they came out with the K-28 and a better motor at 38:3.1. I'm telling you this not to drive you away but to explain how I got to where I am now. With the info given by Jim, I decided to use the 19:7.1 motor Part # GM9413-2, 24V DC, 284 RPM's and will explain why later.

    I dismantled the gear head into pieces. The output shaft has a large gear on it with the size of the output shaft roughly .25"



    This shaft will not fit on the stock Bachmann worm gear so it will need to be turned down. I do not have a metal lathe so the drill press will have to do. I placed it in the chuck and used two new files to cut down the size. you have to do this very slowly checking the size with a caliper as you go. I stopped just shy of what it read on the old shaft the worm gear came from.



    before you say , hey you shouldn't have placed it in the chuck on that shaft, I know but I didn't want to damage the splines above. I was able to clean it up with no ill affects.

    Remember all those wonderful gears in the head?




    Well I found that by removing all except the main gear on the motor and the gear running against it and adding the shaft gear gave me pretty close to what I wanted for RPM's at the wheels. This was all trial and error. If I tried to do the math again I would still be trying to figure it out. In order for me to use the shaft gear to mate with the lower gear I needed to move it down the shaft. You can see it in the back ground. These are the gears left after I removed the extra ones.



    Here is a picture with the shaft gear back in place.



    There is a sleeve and a Teflon grease deflector that still needs to be installed. Ill put it back together and install. once I do that I will record a video and put the link up. I am thinking I will be upgrading to an 18 volt battery just to give a little more top end speed.

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  • BurleyJim
    replied
    Bill,

    Yep, you got it! Motor reduction would be 2837 /900 = 3.15, so 3 to 1 will get you about right where you want to be. What a fun exercise.

    Good luck!

    Jim

    Leave a comment:

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