Abstract: A control apparatus for a linear motor, having main and auxiliary driving coils and which drives a movable plate is disclosed. The control apparatus, which determines if the plate is within an active area of the motor and, if so, supplies current to the coils, includes an alarm circuit for generating a first measuring signal dependent on the current flowing through the main coil and a second measuring signal dependent on the current flowing through the auxiliary coil. The phase relation between the two measuring signals changes depending on whether the plate is within the active area of the linear motor or not. The alarm circuit senses the measuring signals and generates a switch signal at a first output and an engaged signal at a second output if the plate is within the active area of the linear motor. The switch signal is coupled to an adjustable delay circuit which transmits the delayed switch signal to a switching circuit to actuate a switching medium connected in series with the linear motor.