Abstract: In an electronically commutated motor, both the driving current (i2) and the braking current (i2′) are monitored. When excessive driving current occurs, a pulse duty factor which regulates the current is reduced. When excessive braking current occurs, this pulse duty factor is increased. For this purpose, an analog circuit with two current limiting members is disclosed, as well as a circuit in which these functions are implemented by software in a microcontroller, so that current measurement can be dispensed with. Finally, a combination of these features is disclosed, in which hardware current limitation and software current limitation work together.

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: An electronically commutated external rotor motor has an external rotor having a cup-shaped housing and a radially magnetized permanent magnet connected in the cup-shaped housing. An interior stator is positioned in the cup-shaped housing. The interior stator has a laminated core having grooves. Windings are provided within the grooves. The windings have first end turns proximal to a bottom of the cup-shaped housing and second end turns positioned distal to the bottom. The first and second end turns electrically connect the windings to one another. The permanent magnet has an end face remote from the bottom of the cup-shaped housing. At least one galvano-magnetic rotor position sensor is arranged opposite the end face of the permanent magnet so as to be located within a magnetic leakage of the permanent magnet and within a magnetic leakage of the interior stator. The at least one rotor position sensor is designed to control current within at least a portion of the windings.

Abstract: An electric motor (12) is supplied with current (i.sub.mot) via a semiconductor switch (14). During operation, the semiconductor switch (14) is driven by a Pulse Width Modulation (PWM) unit 15 using a pulse-formed signal (32). For regulation of the duty ratio of this pulse-formed signal, a first analog signal, which is a function of at least a first motor parameter, is fed to the PWM unit. Further, a second analog signal (STBGR), which is a function of at least a second motor parameter, is fed to the PWM unit for regulation of the duty ratio. As long as the second motor parameter does not exceed a predetermined value, the duty ratio is predominantly controlled by the value of the first analog signal. When the second motor parameter exceeds the predetermined value, the duty ratio is at least predominantly controlled by the value of the second motor parameter, in order to control this second motor parameter through the PWM unit.

Abstract: The invention relates to a method of current limitation in a direct current motor, with the following steps: in successive cycles, the motor is turned on at a predetermined place in the cycle and, after lapse of a predetermined time interval, the motor current is tested in a first test and, if found to be too high, the current is shut off; after lapse of another interval measured from the first test, the motor current is tested again during the same cycle and, if found to be too high, is shut off if it was not shut off previously; after lapse of a third interval, measured from the second test, the motor current is turned on, insofar as it was shut off at either of the two tests, and the cycle is repeated.

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: 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: 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).