Combination of a power supply and an electrical appliance with a magnetic holder

The invention concerns a combination of a power supply, for example a battery pack, and an electrical appliance, for example a control device for an actuator, where the appliance and the power supply are connectable by a rotational connection for relative rotation between the power supply and the appliance. The connection comprising magnetic holding means with a magnetic force in an interaction region between the power supply and the appliance and means for varying the force by rotation of the power supply relatively to the appliance.