| loathar wrote:|
I used some neodyne disk magnets I got at Hobby Lobby.(had them laying around) About 1/4" dia. and 1/8" thick. This motor is riveted together so I just stuck the magnets to the outside of the frame as close to the armature as I could get. I could run the motor with the amp meter attached and add or subtract magnets or move them around and see the effects on the meter in real time. I reached a point where more magnets raised the amp draw and decreased performance. I found 3 worked good. Two on top and one on the bottom. If I get a chance tomorrow, I'll post some pics.
I cleaned and lubed everything and re-assembled it tonight. It ran better. Low speed was a lot better. If I had to assign a # to it, I'd say it improved 10%-15%. Still not flywheel/can motor performance, but it IS an improvement.
Iiiintelesting. I noticed this braking effect, too. I stuck a 5-stack in an old Life Like trainset motor, noted a large improvement, then added another 5-stack beside it and stopped it from running. I think these open frame motors, with their large current capacity, can produce a very great armature magnetic field, but 10 of those magnets was greater and caused a braking force. You may have run into this too.
When you can scrape up the cash, do try the stacked-magnet method I used! $2 buys 4 magnets from K & J, enough for one motor; minimum UPS shipping is ~$6 and would cover a LOT of magnets. I'm not trying to plug K & J, but their shipping was very fast and I am quite pleased. It's really worth trying!
Relevant data: Tyco 0-6-0 #99 went from barely dragging itself around and drawing probably an amp, to drawing .32A free, .52A slipping. I timed speed using a 100 sft stretch of the V&E, and came up with a top speed of 60 mph and a creep speed of UNDER 1 MPH! No BS! This was on a plain-Jane Railpower 1300 cheapie, no pulse power or back emf or anything. It's not silky-silent; I think the nylon-nylon geartrain has to bear some blame there; but at realistic low speeds it's subdued enough. :)
To be fair, I took 99 down completely, cleaned and relubed it, and threw some pennies in the tender to improve electrical contact (a big reason for poor running, it turns out). I also discovered something about the PM-1. I have a few spare ones, and discovered that the older ones have a lot less "cogging". The armature slots are about half as wide on them. So the Tyco wide-slot armature was switched out for an older one.
The real shocker was that Tyco Switcher in the photo above. It's a later model, with a very cheapo Hong Kong variation on the classic Mantua Plymouth chassis. It was loud, fast, and generally obnoxious. After ordering more magnets, I stuck a 4-stack in it, tweaked it a bit (the pole pieces are only held on by magnetism now), and BAM! Suddenly the beast can crawl less than 1 mph, and is quiet and powerful...and these have a wide-slot armature. You can actually throttle it down low enough on plain old DC that it takes several seconds to travel from tie to tie. To me, this was little short of a revelation. As for power, I balanced a heavy die-cast hulk of a John English 2-8-2 on it, and that four-wheeler didn't even try to stall.
I just can't stress it enough. These magnets are the closest thing to a magic bullet for those old open frames. Their armatures can safely handle hefty currents, and produce a lot of power, but the magnets let them down. Upgrading these gives huge torque. And there just aren't many problems that can't be overcome somehow by adding more torque.
Try it, you'll like it.
Addendum: Part number for the magnets used is B842. http://www.kjmagnetics.com/proddetail.asp?prod=B842