Has the gluing improved on this 170 kV turnigy SK motor?

[swbluto]

I've heard complaints about loosening magnets and looking at the glue on my original 200 kV hxt motor and those complaints were understandable: The glue was practically non-existent on some magnets!

However, I just got the SK in and it appears to be a little better glued than that one. I'm wondering, does this actually need glue? I'd rather be safe than sorry, but it seems like it's not too bad. I'm wondering if anybody who has owned this motor knows if they've actually improved or if the looks of it is deceiving me.

Here's the worst spot on the motor I could find.

 

[gwhy!]

Hi swbluto,
I have 2 of these motors and the glue looked about the same as yours but I did add more glue to be on the safe side.

 

[spinningmagnets]

I have not done this myself (but has that ever kept me from commenting?...) I don't think the glue thats in-between the magnets does much in the way of attaching the magnet. IMHO, as I understand it if we imagine two side by side magnets with a stator pole at the position in-between them...the magnet poles are alternated N-S-N-S...when the stator is energized...Its pole attracts the magnet that is oppositely polarized, and repels the other.

So, one magnet is pulling on the stator, and its neighbor is pushing. I believe the magnets are being pushed to their left and right, rather than in and out. (or possibly both?). Perhaps frquent side-to-side vibrations are loosening the backing glue?

I recall reading in otherpower.com where conventional electric motors (used, cheap) are converted to permanent magnet motors (PMM's) so they could be used as a wind-gen...by removing the rotor coils and replacing them with a metal drum with Neo magnets attached (always glue, but often adding a stainless-steel screw through the magnets center). They often made a cylindrical cage with slots for the magnets to slide into, which would give the magnets firm side-by-side support (out of aluminum or fiberglass).

Couldn't find a pic of the aluminum ones for bar magnets, heres a fiberglass one using button magnets:

 

[spinningmagnets]

Heres a pic of inrunner rotor magnets that were filled in with epoxy resin:

 

[swbluto]

Oh, cool.

I ended up using Uhu Endfest 300 which is a recommended magnet glue. Since the magnets were rated "SH", I also cooked it at 110 degrees C since that little more than doubles the strength of the epoxy (It also speeds up the drying process to like 10 minutes instead of a day).

 

[mwkeefer]

sw,

Could you post a link to the epoxy you used?

Have you spun this motor up, what are your findings?

Balanced?

I think I found a solvent (and method) of disconnecting the delta termination... I'm working with another guy on here back channel who has tons more experience than me (sent him a motor too) and the goal will be simply Wye terminated for approx 100 kV and a tad better efficiency.

I've spoken with many RC guys now and it seems the Infineon / Hall setup works well but it works better in Wye than in delta... I know wye is a tad easier on the controllers so it is very important to me to acheive conversion on these motors...

How are you planning on using yours?

-Mike

 

[spinningmagnets]

The pics are from someone elses project over at otherpower.com, for home-made wind-generators. You would have to search their forum, but the most popular epoxies should be easy to find.