Hacker 7xl busted! Any tips?

[Ryu James]

so i run Neu motors but i decided to try the german motors recently. i loved my hacker motor but after 2 weeks it busted. i opened it up and a small piece of the magnet had busted away from the shaft and kind of grinded against the windings. here are some pics the show better. anyway, i removed the broken particles and cleaned up the windings and put the motor back together and it feels fine again. havent tried running yet but i wanted to get some feedback. is it safe to run or will it not work right? is there anywhere i can get a replacment rotor for a hacker? if it does run will it have same power as before in its current state?

[zeropointbug]

Well if you completely clean up the magnet segment that broke apart, and if there is no play in that last segment there, then it could be run. I am not going to recommend running it that way from now on without it being serviced (rotor replacement).

The Kv. might change a bit, and you will have less torque, but maybe not noticeable.

You would have to make sure that there are no remaining pieces of magnet left over, as any imbalance may be catastrophic. I wouldn't take much at 40,000rpm to cause the thing to vibrate itself into destruction.

[emaxxnitro]

Originally Posted by zeropointbug

Well if you completely clean up the magnet segment that broke apart, and if there is no play in that last segment there, then it could be run. I am not going to recommend running it that way from now on without it being serviced (rotor replacement).

The Kv. might change a bit, and you will have less torque, but maybe not noticeable.

You would have to make sure that there are no remaining pieces of magnet left over, as any imbalance may be catastrophic. I wouldn't take much at 40,000rpm to cause the thing to vibrate itself into destruction.

yeah i would keep it under 40k. its rated for 60-80k new so you must have really pushed it hard lol

[lutach]

Funny, my C50 XL motors have they rotors wrapped with Kevlar. If there's no coil damage, you should be ok. Clean out the rotor like mentioned here and fill that gap with some epoxy and wrap the rotor so that doesn't happen again.

[lincpimp]

Use jb weld to fill the gap. Anything else will not have the heat resistance to hold up. You may also want to balance the rotor again, no idea how to do that with conventional or magnetic balancers, you need a plastic/non ferrous balancer to balance a magnet assy.

[himalaya]

Note the magnet location has changed, you may need to adjust the shims one the shaft to move the rotor a little bit forward, allowing maximum coil-to-magnet reaction area.

[florianz]

sorry about that.
you should send that rotor to hacker. not good for such an expensive motor.

It is a quite "common" problem, that's why the new rotors/magnets are covered/wrapped with a thin metal tube.
Just recently there has been a thread in the forum about that topic, with some pics.