Abstract: A safety system for a rotary saw or other dangerous machine tools features a flesh-sensing circuit (14, 19), located on a safety guard (16) surrounding a dangerous machine part, which generates an electronic signal to trigger emergency stopping of the machine before the operator can contact the dangerous machine part. The stopping means preferably employs DC injection, winding current direction reversal and/or electromagnetic motor braking, in the event of detection of operator contact with the safety guarding device. The system is adapted to be used both with newly-manufactured machine tools and by retrofitting onto previously-manufactured machine tools, by in-the-field modifications.

Abstract: An electronically commutated motor has a rotor (34) that is rotatable about an axis (D), and it has a stator arrangement (30) in which is provided a number, evenly divisible by three, of salient stator poles that are wound with winding strands, associated with which, for the connection thereof, are busbars (44, 46, 48) arranged on edge. The latter are arranged in an insulating part (42). Each of these busbars (44, 46, 48) has a central portion (78), a first end portion (90) and a second end portion (56). These busbars (44, 46, 48) are insulated from one another and are nested into one another in a manner that minimizes relative displacement thereof.

Abstract: An electric motor (10) has: a stator (12) and a rotor (14) having a shaft (87). The rotor (14) has a sensor magnet (82) having a number SP of sensor poles (71, 72, 73, 74) for generating a predetermined distribution of the magnetic flux density, such that SP=2, 4, 6, 8, etc. The motor also has at least two rotor position sensors (450, 455, 460, 465) for generating rotor position signals (B_S1, B_S2) characterizing the magnetic flux density, the rotor position sensors (450, 455, 460, 465) being arranged in the region (30) of the circumference of the sensor magnet (82). The motor also has an evaluation apparatus (32) that ascertains, from the rotor position signals (B_S1, B_S2), an absolute value (phi_el, phi_mech) for the rotational position of the rotor (14). A method of generating an absolute value for the rotational position of an electric motor is likewise described.

Abstract: A miniature fan, particularly an axial fan, has a space-conserving structure which permits sophisticated electronic control circuits within a limited amount of space. It features an electronically commutated motor (ECM) including an internal stator 68, an external rotor 27 on a shaft 62, and a fan wheel 28 mounted on the rotor and bearing fan blades 26. The motor flange 40? supports a bearing tube 60 which rotatably journals the rotor shaft 62 and is formed with a cavity 84 which receives a first circuit board 86 devoted to control of motor speed and/or voltage, and a second circuit board 96 which supports a galvanometric sensor 100 which senses the rotational position of the rotor, for purposes of triggering commutation of the motor stator windings 68 at appropriate times.

Abstract: An arrangement for dissipating heat from components producing high heat flux densities, such as computers, features a combination fan and fluid pump with a magnetic coupling (93) which acts across a fluid-tight partitioning can (52). The pump has a pump wheel (90) connected to a first permanent magnet (92), and an electronically commutated internal-rotor motor (ECM 70) to drive it. The motor has a stator (68) inside which is rotatably arranged a rotor (60) equipped with a second permanent magnet (64). Interaction between the first and second permanent magnets creates the magnetic coupling (93). The stator (68) of the internal-rotor motor (70) is arranged radially outside the magnetic coupling (93). A first shaft (54), arranged on the outer side of the can (52), serves for rotatable journaling of the rotor (60) of the internal-rotor motor (70) and a second shaft (50) inside the can serves for journaling the pump rotor.

Abstract: An electronically commutated one-phase motor (20; 20?) has a stator having at least one winding strand (30, 32; 30?), and it has a permanent-magnet rotor (22) that induces, as it rotates, a voltage (uind) in the winding strand. The motor further has an electronic calculation device or microcontroller (26) which is configured to execute, during operation, the following steps repetitively: sampling the induced voltage (uind) in a currentless winding strand, for example, during a half-wave of the induced voltage, in order to obtain a plurality of analog voltage values; digitizing the analog voltage values in order to obtain a plurality of digitized voltage values; and processing the plurality of digitized voltage values to ascertain the instantaneous rotation direction of the motor rotor. The control circuit then can use these data to assure reliable motor start-up, regardless of any external driving forces which occur.

Abstract: A fan arrangement (20) has a fan (24) driven by an electric motor (22), also an apparatus for detecting the electrical power (PIST) consumed by the electric motor (22) during operation; an input apparatus (28) for inputting a desired rotation speed (nSOLL) of said electric motor (22); a converter (26) for converting said desired rotation speed (nSOLL) into a desired electrical power (PSOLL); and a controller (44), which regulates the control input controlling the electric motor (22) in such a way that the difference between the electrical power (PIST) consumed in operation and the desired electrical power (PSOLL) is reduced, in order thereby to improve the air output characteristic curve (49, 58) of the fan arrangement (20) at least in a portion of the overall operating range.

Abstract: An arrangement for conveying fluids has a fluid pump (91) implemented in the manner of a centrifugal pump, having a pump wheel (90) that is connected to a first permanent magnet (92). The arrangement further has an electronically commutated internal-rotor motor (70) having a stator (68), inside which stator is rotatably arranged a rotor (60) that is in turn connected to a second permanent magnet (76; 140) that coacts with the first permanent magnet (92) in the manner of a magnetic coupling (93). The arrangement also has a partitioning can (52) that separates the first permanent magnet (92) of the magnetic coupling (93), which magnet is arranged inside said partitioning can (52), in fluid-tight fashion from the second permanent magnet (76; 140) arranged outside the partitioning can (52), the stator (68) of the internal-rotor motor (70) being arranged substantially in the same drive plane as the magnetic coupling (93) and radially outside the latter.

Abstract: A fan unit has a fan (10). Associated with the fan is an air-guiding tube (22) through which the fan (10) transports air, during operation. The air-guiding tube (22) is connected to at least one carrier tube (23) for suspension of the fan (10). The fan includes a carrier part (25). A damping member (30) is arranged between the carrier part (25) and the carrier tube (23) to reduce any structure-borne sound which occurs during operation of the fan (10).

Abstract: An electronically commutated motor (20) has a rotor (28) and a rotor position sensor (30), which sensor, during operation, furnishes a rotational position signal (34). A stator interacts with the rotor (28). The stator has a stator winding strand (26) in an H bridge (22), and a control apparatus (36) which, during operation, performs the steps of: (A) controlling the H bridge (22) so that current pulses (+i1, ?i1) flow through the stator winding strand (26), in alternate directions, each pulse starting at a first point in time (t1); (B) at the beginning of each commutation, starting from a second point in time (t2), operating in short circuit the winding strand (26), in order to cause a decreasing loop current (I*) through the stator winding strand (26), which loop current (I*) reaches zero at a third point in time (t3); and (C) stepwise modifying, toward a minimum, the time interval (TCC) between the first and third points in time (t1, t3).

Abstract: Due to variations arising during manufacturing, axial fans often are slightly imbalanced, resulting in noise during operation, which is undesirable in many contexts, for example when the fan is used for ventilation purposes in a motor vehicle. A fan with improved vibration and noise damping can be achieved by elastically suspending the fan wheel within a first ring formed of a hard plastic, the first ring having a tubular extension formed of a softer plastic, and serving to mechanically connect the first ring to a surrounding annular carrier part. Optionally, the first ring and extension unit can include a spring element. Preferably, the first ring and tubular extension are produced by a multi-component forming technology such as two-plastic technology. The fan is preferably driven by an electronically commutated motor (ECM).

Abstract: An electric motor has a rotor (52) and a stator (60) equipped with salient poles on each of which is provided a winding (88 to 99), which windings together form a winding arrangement (85?), electrical connecting leads (88? to 99?) being provided between at least some of the windings. The stator (60) further has electrical connecting elements (108 to 119) that are arranged on at least one insulating carrier (102) and are equipped with contact elements (108? to 119?) and with mounting elements (108?? to 119??), which latter serve for electrical and mechanical connection to the connecting leads (88? to 99?). The use of a printed circuit board (140) formed with press-fit seats, to receive the contact elements, facilitates rapid, secure and automated connection of stator windings to other circuit parts, which is particularly useful in making low-voltage, high-current motors such as those used in mining.

Abstract: A fan for cooling a circuit board (26) has a fan wheel (10; 10?) that is adapted for rotation about a rotation axis (11) and in a predetermined rotation direction (14), and an outer wall (18) that is rigidly joined to an inner wall (16). Defined between the two walls (16, 18) are curved air-directing conduits (39) that extend from an axial air entrance opening (40) to a radial air exit opening (42). The axial air entrance opening (40) is at a lesser distance from the rotation axis than the radial air exit opening (42), and the air-directing conduits (39) are separated from one another by air-directing blades (30, 32, 34, 36, 38) that each extend, oppositely to the predetermined rotation direction (14), from a point between two adjacent air entrance openings (40) to a point between two adjacent air exit openings (42).

Abstract: An improved health and safety system for a table saw includes one or more of: a blade guard that protects the operator from the saw blade, and contains and collects sawdust; a proximity detector and emergency saw motor braking means for use in connection with such blade guard; an anti-kickback device for use in connection with such blade guard, a rip fence adapter for use in connection with such a blade guard, and hoses and fittings to connect the dust containment and collection system of said blade guard to a shop dust collection blower or vacuum system. The system protects the saw operator from potential traumatic injury to a hand, and from ingesting potentially carcinogenic sawdust.

Abstract: An electronically commutated motor (ECM) often employs a Hall sensor for reliable operation. Even when a Hall sensor is omitted from a motor having a plurality of stator winding phases (24, 26) and a permanent-magnet rotor (22), one can reliably detect direction of rotation of the rotor by the steps of: (a) differentiating a voltage profile obtained by sampling either (1) induced voltage in a presently currentless phase winding or (2) voltage drop at a transistor, through which current is flowing to a presently energized phase winding, and (b) using such a differentiated signal (du—24?/dt, du—26?/dt) to control current flow in an associated phase winding. In this manner, one obtains reliable commutation, even if the motor is spatially separated from its commutation electronics.

Abstract: A fan structure, suitable for rack-mounting adjacent to heat-generating electrical equipment, features an improved noise-damping outflow baffle containing a plurality of non-return flaps, serving to prevent reverse flow of air when fan activity is interrupted. In a preferred embodiment, four generally sickle-shaped flaps are used, each connected, along a straight edge thereof, by a pair of elastomeric hinge connections to a surrounding frame. The hinge connections urge the flaps closed whenever they are not forced by airflow into an open orientation. The axes of rotation of the flaps are chosen to keep them from jamming against one another. Since the flaps act as vanes, tending to straighten out an originally helical flow of air induced by the fan, they minimize the pressure drop which has therefore been associated with outflow baffles. The use or elastomers at critical points in the structure reduce noise and clatter.

Abstract: An electric motor has a DC link circuit (30, 32), a permanent-magnet rotor (104), and a control circuit having a full bridge (114). A program-controlled calculation arrangement (80) is configured to supply the semiconductor switches of a first bridge half with a PWM signal (136, 136?) and to supply the semiconductor switches (118, 122) of the second bridge half with a commutation signal (O1, O2; 150, 150?). An energy storage device (170) is provided which, during normal operation of the motor (102), is chargeable from the DC link circuit (30, 32) and serves, upon cessation of the signals from the calculation arrangement (80), to make the semiconductor switches (118, 122) of the other bridge half conductive, and thereby to short-circuit the stator winding arrangement (106) through those semiconductor switches (118, 122) in order to decelerate the permanent-magnet rotor (104) and to thereby minimize risk of human injury.

Abstract: An electric motor has a rotor (52) rotatable around a rotation axis (56) and has a stator (60) arranged around said rotor (52), which stator is equipped with poles (11? to 16?). Each pole has an individual winding (11 to 16), and the latter together form a winding arrangement (30) that serves to generate a rotating field. Arranged approximately concentrically with the rotation axis (56) is an arrangement having electrical connection elements (U, V, W, U?, V?, W?). The latter are equipped with mounting elements (34, V1, W1, U?1, V?1, 32, 36) to each of which an associated end of an individual winding is mechanically and electrically connected. A connection arrangement (40) has a plurality of conductors (42, 44, 46) each of which is connected, by means of a welded connection (155), to the connection elements of the stator in order to electrically interconnect them in a predetermined fashion.

Abstract: In a method for labeling, a label strip (20) is moved by means of an electric motor (80). Arranged on this label strip are labels (26) of predetermined length (EL) with uniform interstices (SB). The motor has associated with it a position controller (218), also a sensor (44) for sensing a predetermined position of a label (26) when the latter is moved on the label strip (20) relative to the sensor (44). The method has the following steps: in accordance with a stored profile, the label strip (20) is set in motion beginning from a start position (A), a first target position (Z) of the label strip being specified to the position controller (218); during the motion of the label strip (20), a predetermined position (M) of the label strip (20) is sensed; and subsequently thereto, a revised target position (Z) is specified to the position controller (218). This makes possible fast and precise labeling, since the target position can be reached very accurately. A corresponding device has a compact design.

Abstract: An electric motor has a stator (12) as well as a rotor (14) rotatable about a rotation axis (85) and a sensor magnet (82) having an even number of sensor poles (71, 72, 73, 74). The sensor magnet (82) is configured to generate a magnetic flux having a magnetic flux density that changes sinusoidally with respect to the rotation angle. Two analog rotor position sensors (460, 465) are arranged on a support structure (468) at a distance from one another such that, during operation, they generate two sinusoidal signals (B_S1, B_S2) having a phase shift of 90° to each other. A signal generator (90) serves to generate at least one pulse-shaped signal (A, B) from the two sinusoidal rotor position signals (B_S1, B_S2) that are phase-shifted by 90°. The instantaneous rotation speed can be accurately determined from this pulse-shaped signal.