Abstract: A primary-side inverter is connected to three output terminals of six output terminals included in a motor with an open winding structure including windings of three independent phases and a secondary-side inverter is connected to the remaining three output terminals. Direct current power is supplied to the inverters, and a control device performs PWM control on the inverters by using a switching pattern in which the numbers of phases where each is turned on are equal, and in the switching pattern, ON of only an upper is continued in one phase from among the three phase outputs, OFF of only a lower is continued in another phase, and the upper and lower are alternately turned on and off such that mutual phases are opposite in the remaining one phase in one cycle of an electric angle of the motor over a plural carrier cycles in PWM control.

Abstract: A motor control device of an embodiment includes a power supply unit that supplies AC power to a motor; a current detection unit that detects a current flowing through a winding of the motor; a speed and electric angle estimation unit that estimates a rotation speed and an electric angle of the motor based on a voltage outputted by the power supply unit and the current; a coordinate conversion unit that obtains an excitation current and a torque current based on the current and the electric angle; a torque current command determination unit that substitutes a predicted torque calculated based on a mechanical motion equation into a torque component current command value calculated based on a torque expression of a vector control coordinate, to generate a torque component current command value for bringing a difference between an inputted speed command and an estimated speed closer to zero; and a model prediction control unit that applies, to a plurality of predicted currents including a current change ratio de

Abstract: A motor control device of an embodiment includes a power supply unit that supplies AC power to a motor; a current detection unit that detects a current flowing through a winding of the motor; a speed and electric angle estimation unit that estimates a rotation speed and an electric angle of the motor based on a voltage outputted by the power supply unit and the current; a coordinate conversion unit that obtains an excitation current and a torque current based on the current and the electric angle; a torque current command determination unit that substitutes a predicted torque calculated based on a mechanical motion equation into a torque component current command value calculated based on a torque expression of a vector control coordinate, to generate a torque component current command value for bringing a difference between an inputted speed command and an estimated speed closer to zero; and a model prediction control unit that applies, to a plurality of predicted currents including a current change ratio de

Abstract: A novel anti-foaming agent is described which contains a compound produced by an addition reaction ofa mono-substituted poly(alkylene glycol) represented by the general formula:RO(AO).sub.x H (I)wherein R represents a monovalent hydrocarbon group having from 1 to 20 carbon atoms, AO represents a structural unit of an oxyalkylene chain, said structural unit having from 2 to 4 carbon atoms, and x represents a number of 1 to 80, witha polyepoxy compound represented by the general formula: ##STR1## wherein Q represents a residue of an organic compound containing in the molecule thereof 2 or more hydroxyl groups and either of a hydrocarbon chain having from 2 to 20 carbon atoms and an oxyalkylene chain having a polymerization degree of from 2 to 100, said residue having a valence of y and being formed by removing from 2 to 8 active hydrogen atoms from the organic compound, and y represents a number of 2 to 8.

Abstract: A pin-on-disk type wear testing device which has a non-contact type displacement gauge that moves integrally with the pin type testpiece sliding against the disk type testpiece, so that the said pin-on-disk type wear testing device of the present invention can accurately measure the displacement of the pin type testpiece with respect to the disk type testpiece without being affected by the waving motion of the disk type testpiece, the thermal expansion of the whole device, and other factors, thus making it possible to accurately measure the amount of wear of the pin type testpiece.