Old GE Rotating Clock. Please advise.

[Church]

With the old GE flip clocks rotating clocks, do you set the time when plugged in or when they are off? I found a good one that appears to be in working order. I don’t want to cause damage.

[Johan de Jong]

Both are possible to do. Only thing to consider is that you cannot set the time while the minute changes. When that happens you will feel a force on the knob as the motor is pushing to change the minute. Just let go of the knob and wait until the minute has changed.
You can change the time both forward and backward without any problem. But don't speed it too much. It may jam if you try to move too fast.

It is an interesting and good working mechanism. Regretfully the motor driving it is less reliable and may give problems.

[Johan de Jong]

Both are possible to do. Only thing to consider is that you cannot set the time while the minute changes. When that happens you will feel a force on the knob as the motor is pushing to change the minute. Just let go of the knob and wait until the minute has changed.
You can change the time both forward and backward without any problem. But don't speed it too much. It may jam if you try to move too fast.

It is an interesting and good working mechanism. Regretfully the motor driving it is less reliable and may give problems.