Abstract: A memory device, e.g. a capacitor, is provided for a collectorless DC motor. This component is charged whenever a particular rotor position is reached. In so doing, a voltage value or quantity on this memory device is changed. This quantity is compared to another quantity, which is dependent on a desired parameter, e.g. ambient temperature or gas or dust concentration. A reference signal is produced when a particular reference criterion is satisfied. The difference between the beginning of this reference signal and a second predetermined rotor position, which follows the initial predetermined rotor position with respect to time, is measured, and on the basis of this measurement, the current flow of the collectorless DC motor is influenced or regulated. In particular, the current can be toggled on and off as the rotor passes certain predetermined positions.

Abstract: An electronically commutated motor (10) has a permanent-magnet external rotor (58) and an inner stator (20) with claw-poles (30,32; 44,46). Preferably, the claw-poles extend axially from opposite directions along the outside of the stator (20) and are interdigited. A galvanomagnetic sensor (14) generates a rotor position signal, based upon measurement of a stray or cross-flux field (.phi..sub.1) of the rotating permanent-magnet external rotor (58,66). Between the claw-poles of the stator (20) are a plurality of neutral field zones (52). The motor turns in a predetermined direction (72) and the galvanomagnetic sensor (14) is positioned adjacent the stator (20) at a location which is circumferentially displaced with respect to a neutral field zone (52), in order to trigger early commutation of current to windings (22,24) of the motor (10).

Abstract: Certain permanent-magnet-rotor electric motors exhibit an irregularity in their torque which is known as "cogging." The present invention creates at least one supplemental reluctance torque, and superimposes this supplemental reluctance torque on the cogging torque, in order to reduce or eliminate the effect of the cogging torque. Preferably, in the rotor, each boundary between north and south poles is subdivided into a plurality of parallel segments, some of which are angularly displaced with respect to others. Four different embodiments have different respective patterns of this displacement. These structures each result in production of a plurality of respective reluctance torques, which superpose and thereby substantially cancel each other. To minimize variation in the magnetically effective air gap, slot closures of ferromagnetic material may be provided.

Abstract: An improved motor for driving a variable-speed fan used, for example, to prevent overheating of electronic equipment, features an electronic controller which sends current pulses through the stator winding(s) of the motor, and varies the slope of trailing edges of these pulses in accordance with at least one sensed operating parameter of the motor, such as temperature of the power semiconductors which control the motor current. The slopes are steepened at high motor speeds to reduce electrical losses, and flattened at low motor speeds to minimize noise. Another feature of the improved motor provides for fail-safe, high-speed operation of the fan when the sensed value of the operating parameter is implausible, for example when a lead from a temperature-dependent sensing resistor breaks. In a preferred embodiment, a bridge circuit is used, which includes a transistor in one diagonal of the bridge circuit.

Abstract: The present invention relates to a method of operating a three-or more-stranded electronically commutated motor which, to detect its rotor position, has a number of sensors which is fewer, by at least one, than the number of sensors intrinsically necessary for this number of strands for controlling the commutation, having the following steps: (a) within each range (120) of rotor positions in which an adequate association between sensor output signals and position is possible, a virtual rotor position signal (H3B') is derived from the output signals (H1, H2) of said rotor position sensors (37, 38), as a replacement for a sensor which is not present; (b) within each range (122, 124) of rotor positions in which an adequate association is not possible, an estimated value (H3B") is used for the virtual rotor position signal, which value is a function of an output signal (H1) of at least one of the existing rotor position sensors (37, 38).

Abstract: This invention relates to a diagonal fan with a truncated cone shaped hub (4a) of the fan wheel (4) and a truncated cone shaped air housing (2). The angle of the truncated cone of the hub (4a) and of the truncated cone of the air housing (2) are relatively small, the outlet cross section (15b) of the flow channel (15) is slightly narrower than the inlet cross section (15a), and the exhaust direction (23) of the flow channel (15) retains these angles, i.e. it is not deflected by any additional deflector walls.

Abstract: A gas premix burner in which gas and air are mixed in a suction region of an impeller to form a combustion mixture. The impeller is associated with a blower housing and an electronic control circuit board, all of which are arranged upstream in a blower chamber having at least one time separating wall. The arrangement prevents the gas and the combustion mixture from reaching the motor landings or the primed circuit board.

Abstract: An improved power supply for converting any of various standard national AC network voltages to low-voltage DC power suitable for driving a 1 or 2-watt device, such as a fan, features a semiconductor control circuit (18, FET 46) which chops each half-wave of a rectified voltage and uses the low-voltage portions to feed charging current pulses to a storage capacitor. The voltage on the capacitor (14) is used by other portions of the circuit to regulate rotation speed of the fan or other consuming device (40) to a value set on a variable resistor. The use of the low-voltage portions of the input signal reduces power losses and increases efficiency.

Abstract: The invention pertains to a bridge circuit and a drive circuit for it, in particular for driving a brushless DC motor. The bridge circuit exclusively consists of n-channel field-effect transistors. An auxiliary potential generated by at least one potential sliding capacitor is provided for driving these particular field-effect transistors which are connected to the positive supply voltage. The auxiliary potential is already built up before the starting of the motor by means of special switching measures, and said auxiliary potential exists at a defined intensity during extended standstill times of the motor.

Abstract: An impeller for a fan comprising a hub for rotation by a drive rotor and a plurality of fan blades for rotation with the hub, the impeller further comprising a support or guide member supporting or connecting fan blades of said plurality, and wherein one or more pockets are provided in said support or guide member and open axially of the fan for receiving balance weights.

Abstract: An electric motor (10) particularly a low-voltage collectorless dc motor, has a microprocessor (18, 40) with a reset input (24). Further, it has a device (26) which, during the running of the motor, generates signals (R) which depend upon the rotational position of the rotor (14) of the motor (30). These signals are applied to the reset input (24) and have the effect that the microprocessor is reset to predefined starting states or conditions, at times controlled by the turning of the rotor (14).

Abstract: It is an object of the invention to provide a transistorized full-bridge driving circuit for an electronically commutated collectorless dc motor, in which burnout of the pnp transistors from overvoltage is avoided.

Abstract: A brushless direct current motor is energized by a power stage. Switches of the power stage are selectively switched by an electronic control device. In order to determine the correct commutation pattern, without using rotor position indicators such as Hall effect devices, the control device is arranged to sample the power fed to the motor. The samples, each responsive to a test signal or normal energization pulses received by the motor, in a ordered sequence define an analogue function whose parameters can be determined by mathematical analysis. The analysis applied to the samples derives the necessary commutation information and the energization signals in a rapid manner by employing a vector or complex number addition based on functions dependent on variable inductance in the operation of the motor.

Abstract: Axial retaining ring is provided for a free end of a rotor shaft of an electric motor having a rotor, with a first stop element on one of the shaft or the rotor and a second stop element in the form of a retaining ring which, during assembly of the motor, is fitted onto the free end of the rotor shaft and is secured by engaging in a circular recess on the shaft free end, both stop elements of the rotor acting between two stationary stop faces of the electric motor and fixing the axial position of the rotor. The retaining ring is constructed in the form of a resilient pushbutton fittable in the axial direction onto the shaft end and the retaining ring having generally axially directed resilient retaining arms that engage in the circular recess provided in the shaft end.

Abstract: In order to reduce the cost of producing an in-hub motor, which consists of a hub and the motor which is located in this hub and which contains magnets, magnetic yokes, coils, and shieldings, the hub (2) made of magnetizable steel is coated at least on the outer surface (20) with a noncorrosive coating which is reduced by means of final machining in the completed state of the motor.

Abstract: A brushless direct current motor is energized by a power stage. Switches of the power stage are selectively switched by an electronic control device. In order to determine the correct commutation pattern, without using rotor position indicators, the control device is arranged to tap the power fed to the motor. The samples received by the motor, in an ordered sequence, define an analogue function whose parameters can be determined by vector addition. The computations applied to the sample enable the necessary commutating information and signals to be generated in a particularly rapid manner.

Abstract: A drive circuit for a brushless direct-current motor, particularly a fan motor, which permits a flexible control or regulation of the power delivered to the direct-current motor depending on a desired or reference value. The drive circuit consists of power output stages which are supplied via a rectifier circuit direct from the a.c. supply, while the control of the power output stages is effected by a special control circuit. This control circuit is supplied via an auxiliary supply part from the a.c. supply. The control circuit delivers ramp-shaped output pluses each driving a control pulse for the motor current which comprises within each commutation phase a pulse that can vary from a symmetrical triangular form to a trapezoidal form. The driving circuit includes a restart circuit which supplies a separate supply voltage to an intermediate drive stage in a fashion which becomes intermittent if the motor is overloaded or blocked.

Abstract: A disk storage drive is provided with a brushless drive motor having a stator with a winding. An external rotor coaxially surrounds the stator and is spaced therefrom by a substantially cylindrical air gap. The rotor includes a permanent magnet and a soft magnetic yoke. A hub is provided that is concentric to the yoke and is connected to the rotor for rotation therewith. The hub has a disk mounting portion on its outer peripheral surface that can be passed through the central opening of a standardized storage disk for mounting the storage disks for rotation therewith. At least half of the axial longitudinal dimension of the stator winding and the rotor magnet interacting therewith is housed within the disk mounting portion of the hub. The hub is made from a non-ferromagnetic material that is suitable for storage drive clean chamber use after dimensional finishing of the hub.

Abstract: A disk storage drive is provided with a brushless drive motor having a stator with a winding. An external rotor coaxially surrounds the stator and is spaced therefrom by a substantially cylindrical air gap. The rotor includes a permanent magnet and a soft magnetic yoke. A hub is provided that is concentric to the yoke and is connected to the rotor for rotation therewith. The hub has a disk mounting portion on its outer peripheral surface that can be passed through the central opening of a standardized storage disk for mounting the storage disks for rotation therewith. At least half of the axial longitudinal dimension of the stator winding and the rotor magnet interacting therewith is housed within the disk mounting portion of the hub. The hub is made from a non-ferromagnetic material that is suitable for storage drive clean chamber use after dimensional finishing of the hub.

Abstract: A permanent magnet excited motor is provided with a plurality of low circumferential hump-like protrusions on the face of each stator pole to partially decrease the air gap between the stator and rotor and act as so-called magnetic cams to exert a force on the rotor to smooth an otherwise uneven parasitic slot torque that occurs between the interaction of slot openings of the stator poles and the gaps between the permanent magnet poles of the rotor.