Login
or
Register
Home
»
Trains Magazine
»
Forums
»
General Discussion
»
diesel locos how do ?
Edit post
Edit your reply below.
Post Body
Enter your post below.
[quote]QUOTE: <i>Originally posted by oltmannd</i> <br /><br />[quote]QUOTE: <i>Originally posted by stpaul</i> <br /><br /> <br /> I've always wondered how a diesel loco can move such great tonnages without stripping the teeth off the motor shaft also just how the gear is attached to the motor?? how does it all work together has baffeled me since the mid-50's. Is there a book on this that doesn't get all big worded and thecnological but just puts it into the average persons language? new to this site I think I'm in the right area to post this question. <br />[/quote] <br /> <br />I think your question is about the traction motor gearing, in particular the pinion gear on the motor shaft. <br /> <br />The first step is to find out the maximum torque the motor can produce. This is what you need to design to. The pinion is fit onto the shaft with an interference fit. That is, the inner diameter of the gear is less than the outside the diamter of the shaft so that there is constant pressure between the gear and the shaft. The total area of contact between the two determines the amount of force that can be transmitted before it slips. <br /> <br />The size and shape of the gear teeth determines how many teeth are in contact at a time and what the contact stresses will be. The gears can be case hardened or induction hardened to improve the overall strength and wear characteristics. <br /> <br />Finally, the lubrication system needs to designed. The lubricant has to be able to minimize tooth wear which would cause severe vibration. <br /> <br />The basic design on an EMD traction motor has actually changed little over the years, even as maximum torque has increased. The design has been tweaked to allow for higher forces, though. Most notably, the tooth design changed with the advent of the SD50s, allowing an increas in the number of gear teeth in contact at a time, although they are smaller teeth. <br /> <br />And, the lubrication has gotten better over the years. In the early years, an asphalt based compound was used ("crater"). Specially formulated greases replaced crater compound as the years went by. These greases were compounded with extreme pressure additives and went through extensive testing on the RRs before being adopted. New locomotives these days use oil to lubricate the gearing. <br /> <br />The gearing has been a source of trouble for years. Slipped pinions, which generally result in the armature overspeeding and coming apart, are fairly rare, but a big problem to deal with when they occur since you can't move the locomotive until you get the motor out of there. Worn gearing has been another source of trouble. Keeping grease on the teeth during sustained 60 mph running is difficult. Worn gears create vibration which causes the motor windings to short. <br />[/quote] <br /> <br /> <br />Regarding moving locomotives with damaged traction motors and pinion gears, while working for the railroad during the summer of 1979, I watched a Diesel Supervisor cut a pinion gear shaft off of a damaged SD-40. He lay on his back between the fuel tank and traction motor and used the largest cutting torch I ever saw. It took quite a while and the temperature that day was close to 100 degrees. Once he got the gear out, the locomotive could be moved "dead". This technique would only work if you could get access to the damaged traction motor. As I remember most SD-40's and GP-38's had a big gap between the trucks and the fuel tank. <br /> <br />
Tags (Optional)
Tags are keywords that get attached to your post. They are used to categorize your submission and make it easier to search for. To add tags to your post type a tag into the box below and click the "Add Tag" button.
Add Tag
Update Reply
Join our Community!
Our community is
FREE
to join. To participate you must either login or register for an account.
Login »
Register »
Search the Community
Newsletter Sign-Up
By signing up you may also receive occasional reader surveys and special offers from Trains magazine.Please view our
privacy policy
More great sites from Kalmbach Media
Terms Of Use
|
Privacy Policy
|
Copyright Policy