You may have a problem with the compressor clutch.

The compressor pulley is actually the clutch pulley. It is magnetically operated, making a distinct "clack" when it engages.

When it is not engaged, the pulley spins free. The center pieces, which are connected to the compressor shaft, are fixed. Watch for a while. If the clutch is not engaged. the pieces in the center, often three, remain fixed. Easy to see. Hand-turning the compressor is really just turning the pulley unless the clutch is energized.

If the clutch is damged somehow it can drag, not be free when de-energized. Or is can fail to make secure contact with the compressor shaft, just grabs and slips and grabs and slips, etc.

When the a/c has been running, the refrigerant is compressed on one side of the evaporator, and at a much lower pressure on the other side. Starting the a/c then has the compressor under a start-up load. When allowing time to "cool down" the pressure between the high side and the low side to equalize, so starting the a/c then has a much lower compressor load.

Hope this is helpful.

Good Luck,

Bob

:>)