On a Belimo Damper Actuator AMB 24-3, the black wire is the common wire and the white and red wires are used to determine the direction the actuator runs. Is this correct?

How does a person test a wire to find out if it is the common wire?

Never seen a Belimo before. Remove the wires at the transformer secondary and use continuity common should have nearly 0 ohms to chassis ground.