Ok, Magnets glued. I took pics, may host them if people wish. Specific issues:1) This magnet had a nice crack in the middle but did not break apart. Don't worry, it will break in two while you're smoothing the back. It's the way life is, don't try to fight it.
2) This one had some sort of paste all over the back of the magnet. Factory applied, I never fixed this one before (I mark them) so eh. Cleaned out the magnet housing with a small wire brush on the drill, then wiped it down with simple green to clean the old debris off.
3) Magnet went to the wire grinder brush and broke while cleaning. No big deal, the goal is not to have it break further. Take off any little magnet crumbs and smooth the back of it. Remember any uneven-ness will just be a stress spot that will cause it to crack again.
4) When it breaks mark the top of each piece.5) When installing a broken magnet I'll first put JB Weld on the back of the part with the crack that allows me to install the second from the top. It never breaks perfectly straight, and it's better to have the big end of the crack on the bottom of the shell when installing from the top.
6) Put it in and line it up vertically to the old dirt markings on the wall of the motor. Then use one of your two side gauges to get it in line with the good magnet. It will stick and stay, making the next part easier.
7) JB Weld the other magnet half including the break part. Put it in the shell and push against the good magnet to get it to interlock tightly. Then use your second side gauge to press it against the first magnet and the wall. At this time it's nice to install the center gauge and check to make sure the magnets are pressed against the wall.
8) Once it looks good slide the side gauges down more to really press them against the wall and each other. Make sure it's about the right height, I think a tiny bit high is better than a tiny bit low. Once again check with your center gauge to make sure the magnet is not going to interfere with the central armature.
9) Clean any residue JB Weld from the magnet face and motor shell walls. Might as well be neat and do it before the JB dries.
10) If you took off the two metal end strips, put them back on now with some JB Weld on their backs. Hold them in place for a few mins to let the glue set. They will protect the top and bottom of the crack which is a good thing.
11) I did rub some JB Weld into the crack, but then wiped it off the magnet. I don't think it's necessary for the crack to be smooth, just filled properly.
12) Wait 24 hours at least before putting the armature in. Note the magnets pull towards the armature, so if they are drying that will be a.... mess. Leave your center gauge in.
That's about it. I've done this on several fat mower motors and have never had the magnet drop again. Likewise I did this to two of the magnets on a Elec-Trac vacuum blower, they are still in fine shape and I do check them every year before firing it up (turn the impeller, listen for a clack or clunk)
C On 4/14/2024 11:21 AM, Seth wrote:
I am looking to get rid of my elec-track. I have a tiller, plow, mid mount deck. (Tall skinny motors?) a spare motor. An E15. It’s a bit rough. I am 45 minutes north of Boston. It’s still useable. The deck linkages need some work/attention. If it was 4WD I could use it. Also have saft 100Ah ni cad modules for it. Never installed I’d be interested in offers. Thanks, Seth Sent from my iPhone. Please excuse the brevity and typos.On Apr 14, 2024, at 10:42, Christopher Zach via Elec-trak <elec-trak cosmos phy tufts edu> wrote: After mowing for a bit I noticed the central motor was not running right and overheated. Lifted the deck to check it, felt a small clunk as I moved the blades clockwise then counterclockwise. Means one thing: Magnet dropped. Large diameter motors just. do. this. Popped off the lid to check: Yep one magnet is loose. I'm sure when I drop the blade and armature this morning I'll find that the magnet has what I think was double-sided tape holding it to the wall and that tape has disintegrated. Fortunately repair is easy: 1) Mark the top of the magnet BEFORE removal. You can't install it rotated and expect it to work. 2) Remove magnet, clean off the tape with the wire brush on your grinder 3) Clean off the rust and junk from inside the motor housing with your small wire wheel on a drill. 4) Clean everything so no dirt. 5) Find your magnet gauges. For me it's two custom cut plywood bits to gauge the sides to the good magnet and a third that goes across the magnets to provide pressure. 6) Test fit the magnet to verify gauges and pressure against motor wall 6) Mix up a hunk of JB Weld. 7) Apply to back of magnet 8) Using gauges put the magnet in and make sure it's oriented with your Top marking on the top.... 9) Tap in the center gauge 10) Wait 8 hours 11) Re-assemble I wish there were a way to get all of my magnets to drop but that's life with an Elec-trak. By the way if you have motors with broken or dropped magnets don't chuck them, I will buy them as spares. Off we go. _______________________________________________ Elec-trak mailing list Elec-trak cosmos phy tufts edu https://cosmos.phy.tufts.edu/mailman/listinfo/elec-trak