When Does an Object Experience Only Centripetal Acceleration in Circular Motion?

[Riemannenthusiast]

Hey guys,
there's something I've been confused about when looking at circular motion. When does an object have just centripetal acceleration as the acceleration of the object, if ever. I think that the acceleration vector is between the centripetal and tangential acceleration when an objects like in a loop, so the acceleration is in between the two vectors, so it there any time when there isn't tangential acceleration? I feel like I am not understanding something

 

[jbriggs444]

there's something I've been confused about when looking at circular motion. When does an object have just centripetal acceleration as the acceleration of the object, if ever. I think that the acceleration vector is between the centripetal and tangential acceleration when an objects like in a loop, so the acceleration is in between the two vectors, so it there any time when there isn't tangential acceleration? I feel like I am not understanding something

When the acceleration is perpendicular to the velocity.

 

[FactChecker]

If the rotation rate and the radius are not changing, then there is no tangential acceleration. Something sitting on a rotating platter has no tangential acceleration as long as the rotation rate of the platter does not change.