Sebo Vacuum runs intermittently and keeps cutting out and restarting

There could be numerous reasons for this. What I would try in this order to help troubleshoot is this:

1. If you wiggle the power cord near where it inserts into the vacuum cleaner itself, does the vacuum turn on and off constantly? If so, you have a damaged cord or loose connections that need to be fixed.
2. Has the bag been emptied, and if the vacuum has a filter element, has this been cleaned? Vacuums may cutout if they get too hot. A vacuum can overheat if either the bag is full, the filter is blocked, or there are other obstructions to airflow, which cause the motor to work harder and draw more voltage, resulting in more heat. It may have a thermal cutoff which is tripping constantly. Solution is to ensure bag is not full, or less than 3/4 full, any air filters are cleaned and check for any other obstructions in the air flow paths.
3. Ensure the power supply is adequate for the vacuum. Try running it without long extension cords if you have been using those.
4. Check and clean the switch. Sticky or dust contacts on switches can cause variable cycling (cutting out and restarting).

Hope that helps!