Abstract: A control apparatus for a three-phase brushless motor, in which a control circuit includes time interval calculation means (133 in FIG. 4). The time interval calculation means (133) is endowed with at least one time interval calculation mode. In the time interval calculation mode, pluralities of time intervals which correspond to an addition section obtained by adding up two or more Q continuous sections are calculated on the basis of two position detection signals which lie at both the ends of the addition section, among position detection signals successively generated. The control circuit determines pluralities of energization switching timings on the basis of the pluralities of time intervals. The control apparatus for the three-phase brushless motor can decrease the deviations of the energization switching timings attributed to the errors of the mounting positions of position sensors or to the errors of the magnetized positions of a rotor, without requiring any complicated adjustment.

Abstract: A local oscillator and logic circuit pulses the open winding of a brushless DC motor at start up and the back EMF is used to generate a voltage to boost the voltage available to the control circuit for optimizing performance when starting with low supply voltage. As the rotor of a motor rotates and the windings are commutated by the drive electronics there is generated in each winding a voltage caused by the collapse of the current and the inherent inductance of the winding. These voltages exceed the normal operating voltage of the motor. The energy in these voltages is used to generate a regulated power feed to the analogue circuitry of the control circuit at a suitable voltage level. During steady state conditions, when the motor is running, the commutation of the windings is continual and there is ample energy available to power analogue electronics, and, if required, associated digital electronics as well.

Abstract: Disclosed is control circuitry for providing controlling a motor responsive to feedback signals. The control circuit includes a velocity sensor for coupling with the motor for providing a velocity feedback signal responsive to the velocity of the motor, and circuitry for providing a feedback signal responsive to a voltage associated with the motor, such as the back emf of a coil associated with the motor. The control circuitry can be used enhance the Z-axis control of a tool of a work apparatus for performing work operations on a work material, such as a cutting apparatus for cutting a sheet of vinyl having a releasable backing for generating graphic products.

Abstract: The speed of a rotor in a two-winding, permanent magnet motor can be accurately controlled with a dual-polarity pulse width modulation drive signal. The phase back emf signal generated in the non-excited winding is compared against the phase of a command signal and the results of the comparison are used to vary the duty cycle of the drive signal.