An acoustic noise mitigation system for an electric machine includes one or more suspension members. The suspension members may include arcuate members that are positioned between a machine housing and a stator. During operation of the electric machine, the electromagnetic force frequency that is generated by the stator relative to a rotating rotor is able to be absorbed by the suspension members. As a result, acoustic noise generated by the electric machine is reduced.

An acoustic noise mitigation system for an electric machine includes one or more suspension members. The suspension members may include arcuate members that are positioned between a machine housing and a stator. During operation of the electric machine, the electromagnetic force frequency that is generated by the stator relative to a rotating rotor is able to be absorbed by the suspension members. As a result, acoustic noise generated by the electric machine is reduced.

A stepping motor includes a stator, a rotor rotatably supported by the stator, and an auxiliary magnetic member. The auxiliary magnetic member has a body, side edge parts at both circumferential ends of the body, and an opening between the side edge parts. The auxiliary magnetic member is elastically mounted around a flange of the stator. The auxiliary magnetic member includes, at one of the side edge parts, a projecting part protruding radially inward from a projected inner circumferential surface of the body across the opening.

A stepping motor includes a stator, a rotor rotatably supported by the stator, and an auxiliary magnetic member. The auxiliary magnetic member has a body, side edge parts at both circumferential ends of the body, and an opening between the side edge parts. The auxiliary magnetic member is elastically mounted around a flange of the stator. The auxiliary magnetic member includes, at one of the side edge parts, a projecting part protruding radially inward from a projected inner circumferential surface of the body across the opening.

In the case of this motor device, tip parts (230) of first protrusion sections (23), which hold a stator core (60) from inside of a first case (21) in the direction of a rotational center axis line (LO) in conjunction with a second case (22), are tapered toward the stator core (60). Also, tip parts (240) of second protrusion sections (24), which hold the stator core (60) from inside of the second case (22) in the direction of the rotational center axis line (LO) in conjunction with the first case (21), are tapered toward the stator core (60). Thus, when the protruding lengths of the first protrusion sections (23) and the second protrusion sections (24) are set somewhat long in advance, the first protrusion sections (23) and the second protrusion sections (24) hold the stator core (60) in a state in which the tip parts (230, 240) are crushed.

In the case of this motor device, tip parts (230) of first protrusion sections (23), which hold a stator core (60) from inside of a first case (21) in the direction of a rotational center axis line (LO) in conjunction with a second case (22), are tapered toward the stator core (60). Also, tip parts (240) of second protrusion sections (24), which hold the stator core (60) from inside of the second case (22) in the direction of the rotational center axis line (LO) in conjunction with the first case (21), are tapered toward the stator core (60). Thus, when the protruding lengths of the first protrusion sections (23) and the second protrusion sections (24) are set somewhat long in advance, the first protrusion sections (23) and the second protrusion sections (24) hold the stator core (60) in a state in which the tip parts (230, 240) are crushed.

A light fixture including a stepper motor comprising a stepper motor stator and a stepper motor rotor. The stepper motor rotor includes a stepper motor axle and is rotatable around a stepper motor axis. The stepper motor is connected to a movable object and is configured to move the movable object in relation to a reference point. A damping mass is attached to the stepper motor axle. The damping mass has a rotational inertia in relation to the stepper motor axis which is at least as large as the rotational inertia of the stepper motor rotor in relation to the stepper motor axis. A method of damping the sound generated by a light fixture comprising a step of attaching a damping mass to a stepper motor axle.

A light fixture including a stepper motor comprising a stepper motor stator and a stepper motor rotor. The stepper motor rotor includes a stepper motor axle and is rotatable around a stepper motor axis. The stepper motor is connected to a movable object and is configured to move the movable object in relation to a reference point. A damping mass is attached to the stepper motor axle. The damping mass has a rotational inertia in relation to the stepper motor axis which is at least as large as the rotational inertia of the stepper motor rotor in relation to the stepper motor axis. A method of damping the sound generated by a light fixture comprising a step of attaching a damping mass to a stepper motor axle.

A stepper motor is driven according to step driving modes including a full-step driving mode, a half-step driving mode and micro-stepping modes. The stepper motor may also be driven in an acceleration phase. A method of controlling the stepper motor includes controlling the current step driving mode of the motor by a processing unit. During the acceleration phase of the stepper motor and the stepper motor being in driven in a current step driving mode other than the full-step driving mode, the processing unit tests, after each speed increase, if a remaining computing power of the processing unit is sufficient for control of the stepper motor to remain in the current step driving mode, and if not the processing unit, in presence of a first switching condition, switches control of the stepper motor to the driving mode having the closest coarser step.

A stepper motor is driven according to step driving modes including a full-step driving mode, a half-step driving mode and micro-stepping modes. The stepper motor may also be driven in an acceleration phase. A method of controlling the stepper motor includes controlling the current step driving mode of the motor by a processing unit. During the acceleration phase of the stepper motor and the stepper motor being in driven in a current step driving mode other than the full-step driving mode, the processing unit tests, after each speed increase, if a remaining computing power of the processing unit is sufficient for control of the stepper motor to remain in the current step driving mode, and if not the processing unit, in presence of a first switching condition, switches control of the stepper motor to the driving mode having the closest coarser step.