When the CNC vertical lathe is powered off, the following steps should be taken:

1. Safe operation: First, ensure that the CNC vertical lathe is in a safe state, stop all processing operations, and turn off the spindle and all power transmission devices.

2. Save working status: If necessary, record the current working status and processing parameters for reference when resuming processing later.

3. Manual operation: If there is a workpiece being processed on the CNC vertical lathe, use manual operation to move the tool and workpiece to a safe position to avoid accidental damage or injury.

4. Clean the working area: Clean the working area of the CNC vertical lathe, remove chips, cutting fluid and other debris generated during the processing, and keep the environment around the lathe clean.

5. Check equipment: Regularly check various equipment and components of the lathe to ensure that they are in good condition and have no damage or abnormalities.

6. Power-off protection: If the lathe will not be used for a long time, it is recommended to connect it to a power protection device (such as a voltage regulator or power protection switch) to prevent sudden voltage fluctuations from damaging the equipment.

7. Pay attention to safety: When performing any maintenance or adjustment, the power must be cut off and wait for the equipment to stop running completely to ensure the safety of the operator.

To sum up, when handling CNC vertical lathes after a power outage, safety should be the primary consideration, and the equipment and working environment should be kept clean and tidy.