Cause of motor smell / burn out?

I went flying today and after a few flights one of my motors stopped working. I had noticed an issue with this one before but it was fine at the time. Today however I noticed a very strong smell coming from it (no smoke or noticeable damage). What could result in this? / Best way to prevent moving forward? Thanks.

Specs:
1000KV motor
30A esc
1045 propeller
2200mAh, 35C, 3S LiPo
S500 quadcopter X frame

This was my last successful flight log

This was my last log, I believe the one it failed on