Hi , I am sorry to hear that.
I am Tech Michael and I know these machines well. This is one of two things.
Either the thermal fuse is failing and tripping out, or the motor has a short circuit in the armature winding's.
In either instance this one is worth the cost of the repair;-)
If its the motor winding that has a short, it will require a new motor, but it may be a cheap as a thermal fuse (automatic circuit breaker) that supplies the motor with power.
The best thing to do, is take this one to any local vacuum cleaner repair shop, they will know what to test to be sure, and they can fix this for you reasonably.
I wish I had better news for you, I really do. But if you have electronics experience and some test equipment and tools you could diagnose this further with my help, please let me know on that? I am here to help;-)
In any case, I will stick with you until this is complete please rate my service kindly.
Also it is the only way I am credited for my time and expertise with you.
Once you rate, I will be notified and will add your question to my priority list so you can reach me anytime until this problem is solved.
Then you can reach me by simply replying to this message anytime.
Thank you and have a Wonderful day!
No additional cost to rate kind;-)