Abstract: A cable installation apparatus 2 for mounting on a structure 20 having an internal flange 26 defining an opening at one end, comprising a platform 4; a cable winch 14 mounted on the platform; and a base portion 6 for supporting the platform and attachable to the flange of the structure; wherein the base portion 6 comprises at least one guide member 10 adapted to engage with the flange 26 on which the apparatus is to be mounted to guide the same on to the structure. The apparatus in accordance with the present invention allows the same to be quickly, simply, safely and therefore inexpensively installed on a flanged end of a structure, such as a turbine tower section, in a single lifting and alignment operation.

Abstract: A method for attenuating switching noise from back electromotive force (EMF) observations in a motor is described. The motor is controlled by pulse width modulation (PWM) signals provided at a PWM frequency. The method comprises sampling back EMF observed in the motor at a sampling frequency at least two times greater than the PWM frequency to obtain over-sampled back EMF readings. The oversampled readings may be used in a raw or filtered form to commutate the motor. A system implementing the method is also described.

Abstract: A system for controlling a polyphase motor is described. The system comprises phase windings in the motor for energizing stators to cause rotational motion of a rotor of the motor as energy is applied to one or more phase windings, and a bridge circuit having a branch circuit connected to one of the phase windings of the motor. The branch circuit has a first FET, a second FET, and a capacitor to trigger the gate of the first FET. The capacitor is connected at one end to the junction between the first and second FETs. While the second FET is conducting, the capacitor is charging. While the first FET is conducting, the charge on the capacitor alone is used to hold the first FET in a conducting state. A method for controlling the motor with the system is also described.

Abstract: A method for attenuating switching noise from back electromotive force (EMF) observations in a motor is described. The motor is controlled by pulse width modulation (PWM) signals provided at a PWM frequency. The method comprises sampling back EMF observed in the motor at a sampling frequency at least two times greater than the PWM frequency to obtain over-sampled back EMF readings; and filtering the over-sampled back EMF readings to remove switching noise and obtain cleaned back EMF observations. A system implementing the method is also described.

Abstract: Methods for evaluating back electromotive force (EMF) in a polyphase motor is described. The methods include monitoring back EMF in the motor after a commutation of the motor, and evaluating the back EMF only after a back EMF event occurs after the commutation of the motor. The methods may also include monitoring a total current appearing on all phase windings of the motor after a rotor of the motor begins to rotate, and evaluating back EMF only after the total current is within a predetermined margin of the current supplied to the motor. Systems implementing the methods are also described.

Abstract: A method for determining an initial position of a rotor of a polyphase motor is described. The method comprises determining current change values from a plurality of phases of the motor during saturation of the motor relating to the initial position of the rotor; identifying a set of modelled current change values according to a modelled behaviour of the motor, in which the modelled current change values represents modelled positions of the rotor under the modelled behaviour; and comparing the current change values to the set of modelled current change values to identify the initial rotor position from the modelled positions. A system implementing the method is also described.

Abstract: A method for adjusting a rotational speed of a rotor in a polyphase motor from a first speed towards a second, faster speed when the motor is commutating according to a commutation scheme at a first commutation phase angle is described. The method comprises selecting an advanced phase angle relative to the first commutation phase angle for commutating the motor; and adjusting the commutation scheme to be commutating at the advanced phase angle, so that the rotational speed of the rotor increases from the first speed towards the second speed as the motor is commutating at the advanced phase angle. A system implementing the method is also described.

Abstract: A system and method for sensor less control of a stepper motor is described. The system and method includes estimation of the position of a rotor of the motor by way of sensing circuitry on the windings of the motor, without the use of positional sensors. The system and method of stepper motor control further includes magnetic field optimization for increasing the torque generating component of a magnetic field generated by stators of the motor, and magnetic field weakening for countering some of the effects of back electromotive force generated by the magnetic rotor.

Abstract: A cover for an infant car carrier seat of the type which is open facing upward in an inclined position. The cover fits over the upper perimeter of the infant car carrier, to fully enclose the infant reclining or in an inclined position in the carrier. The cover has an opening which is selectively closeable with a flap which can be quietly removably secured across the opening. The opening is aligned with the approximate region of the infant's face, so that the infant can breath easily, and can see out from the cover, and others can see in when the flap is open.