Information about actuators

It would depend on the specific actuator and the specific arrangement.

Generally, you would consider what fail condition you'd like. Should the load drop during a power cut/system failure? Or remain in place?
Think of two valves, one controlling the flow of flammable gas into a reactor and one controlling the flow of cooling water to the reactor. If there's a power cut what should happen? Well, the gas valve should fail closed so the reactor doesn't continue burning and overheat and explode, and the cooling water valve should fail open so the reaction is cooled so it doesn't runaway and lead to the reactor overheating and exploding.