A stepping motor control device configured to drive a stepping motor having a rotor and a coil includes: a train wheel including a load gear which has a load tooth whose rotation load is different from that of another tooth and in which the rotor has an odd number of rotation steps when the load gear rotates once, and transmitting a rotation force from the rotor to the hand; a voltage detection unit that detects an induced voltage generated at one end portion of a first end portion and a second end portion of the coil when the rotor vibrates; and a determination unit which, based on a result detected by the voltage detection unit, determines a mechanical load received by the rotor due to contact of the load tooth of the load gear with a tooth meshing with the load gear.

A stepping motor control device configured to drive a stepping motor having a rotor and a coil includes: a train wheel including a load gear which has a load tooth whose rotation load is different from that of another tooth and in which the rotor has an odd number of rotation steps when the load gear rotates once, and transmitting a rotation force from the rotor to the hand; a voltage detection unit that detects an induced voltage generated at one end portion of a first end portion and a second end portion of the coil when the rotor vibrates; and a determination unit which, based on a result detected by the voltage detection unit, determines a mechanical load received by the rotor due to contact of the load tooth of the load gear with a tooth meshing with the load gear.

A stator assembly, an electronic expansion valve, and a refrigeration device are provided. The stator assembly has a housing, a coil assembly and a fixing member. An outer surface of the housing is provided with an installation opening. The coil assembly is provided in the housing, and has a shell for mounting a coil. The fixing member is inserted through the installation opening to be fixedly connected with the shell, and the is configured to connect with the conducting tube of the electronic expansion valve to electrically conduct the shell and the conducting tube.

A driving circuit drives a stepping motor in synchronization with an input clock using a 2-phase excitation method. A constant current chopper circuit generates a pulse modulation signal such that the detection value of the coil current approaches a current setting value. A detection window generation circuit generates a detection window. The detection window becomes an open state at a timing at which the coil current I.sub.OUT becomes smaller than a predetermined threshold value. A logic circuit sets a full-bridge circuit to a high-impedance state when the detection window is in the open state and controls the full-bridge circuit according to the pulse modulation signal when the detection window is in the closed state. In the open state of the detection window, a back electromotive force (BEMF) detection circuit detects the BEMF of the coil. A current value setting circuit controls a current setting value based on the BEMF.

A driving circuit drives a stepping motor in synchronization with an input clock using a 2-phase excitation method. A constant current chopper circuit generates a pulse modulation signal such that the detection value of the coil current approaches a current setting value. A detection window generation circuit generates a detection window. The detection window becomes an open state at a timing at which the coil current I.sub.OUT becomes smaller than a predetermined threshold value. A logic circuit sets a full-bridge circuit to a high-impedance state when the detection window is in the open state and controls the full-bridge circuit according to the pulse modulation signal when the detection window is in the closed state. In the open state of the detection window, a back electromotive force (BEMF) detection circuit detects the BEMF of the coil. A current value setting circuit controls a current setting value based on the BEMF.

A magnetic resonance (MR) system may include a MR device and a MR-compatible drive. The MR device may include a scanner with a basic magnet for generating a homogeneous basic magnetic field. The MR-compatible drive may include an electric motor with a stator. The stator of the electric motor may include a dominant component of the basic magnetic field of the basic magnet.

A direct current (DC) motor for operation in an external magnetic field may include a rotor which is rotatable about a rotation axis and has at least two windings, at least four continuous rotary transmitters, wherein two rotary transmitters are associated with each of the windings and are configured to supply the associated winding with direct current, an angle sensor which is configured to determine the angular position of the rotor, and a controller configured to control the current feed to at least one of the windings dependent upon the angular position of the rotor. The motor is oriented relative to an external magnetic field during operation so that the rotation axis extends transversely to the external magnetic field.

A dual-drive device for sequential scanning includes a moving part comprising a frame and an optical instrument that is positioned on the frame and is rotatable about a first axis with respect to the frame so as to be slowed down or immobilized in a plurality of successive positions about the first axis, a motor configured to set the moving part in rotation about the first axis in a first direction of rotation at a constant speed, the moving part comprising a first actuator positioned on the frame and configured to actuate the rotation of the optical instrument about the first axis with respect to the frame in the first direction of rotation in order to pass from a first position to a successive position from the plurality of successive positions, and in a second direction of rotation, opposite to the first direction of rotation, in order to slow down or immobilize the optical instrument in the successive position.

A dual-drive device for sequential scanning includes a moving part comprising a frame and an optical instrument that is positioned on the frame and is rotatable about a first axis with respect to the frame so as to be slowed down or immobilized in a plurality of successive positions about the first axis, a motor configured to set the moving part in rotation about the first axis in a first direction of rotation at a constant speed, the moving part comprising a first actuator positioned on the frame and configured to actuate the rotation of the optical instrument about the first axis with respect to the frame in the first direction of rotation in order to pass from a first position to a successive position from the plurality of successive positions, and in a second direction of rotation, opposite to the first direction of rotation, in order to slow down or immobilize the optical instrument in the successive position.

A linear or rotary step motor for moving an object comprising: one or more beam actuators; and one or more auxiliary actuators. Each beam actuator comprises: (a) a flexible beam; (b) two holders holding the flexible beam from the beam edges; and (c) an actuator for moving the said at least one holder in order to bent the beam toward the object or to pull the beam away from the object. The axillary actuators are connected to the one or more beam actuators. The beam actuators configured to grip or release the object, and the one or more beam actuators perform a movement step to the object by first grip the object by the one or more beam actuators then push the object by activating the auxiliary actuator.