The authors examined the reduction in the electrical time constant with the aim of achieving high response in a moving magnet linear actuator (LA). This paper describes the relationship between the mover radius, the slot width, and the electrical time constant of the prototype LA. The electrical time constant of the LA can be decreased by 30% by increasing the mover radius from 11 mm to 13 mm and by increasing the permanent magnet thickness from 3 mm to 4 mm. It can also be decreased by 18% by increasing the slot width from 3 mm to 5 mm.