Abstract:
Die Erfindung betrifft ein Schaltgerät (18) sowie eine Verfahren zum Beenden eines Abbremsvorgangs eines dreiphasigen Drehstrommotors (1). Um für den Drehstrommotor (1) die Wartezeit zwischen dem Ende seines Abbremsvorgangs und einem neuen möglichen Motorstart zu verkürzen wird vorgeschlagen, dass der Abbremsvorgang des Drehstrommotors (1) mittels eines ersten und zweiten Thyristors (5, 6) erfolgt, wobei während des Abbremsvorgangs des Drehstrommotors (1) in einem ersten Schritt der erste Thyristor (5) derart angesteuert wird, dass ein Bremsstrom (20) in den Drehstrommotor (1) eingespeist wird, so dass ein den Drehstrommotor (1) bremsendes Moment entsteht, und in einem zweiten Schritt der zweite Thyristor (6) derart angesteuert wird, dass bei einem Löschen des ersten Thyristors (5) der Bremsstrom (20) vom zweiten Thyristor (6) übernommen wird und das bremsende Moment aufrechterhalten wird, wobei sich die beiden Schritte während des Abbremsvorgangs wiederholen, wobei während des Abbremsvorgangs nach einem letzten Ansteuern des ersten Thyristors (5) der zweite Schritt unterbleibt.
Abstract:
Method for slowing-down control of an asynchronous machine (101), wherein the value of a start energy (Estart) is determined and stored while the asynchronous machine (101) is being run up from being stationary to the operating rotation speed. The asynchronous machine (101) is braked, in the reversing mode, with braking energy (Estop) which corresponds to the start energy (Estart) multiplied by a correction factor (d) wherein the correction factor (d) assumes a value between 0 and 1. The asynchronous machine (101) is braked further by DC braking after braking has been carried out in the reversing mode.
Abstract:
Control features for a wind turbine that control the turbine over a range of wind speeds and under triggering conditions with reduced noise, cost, and reliability issues associated with other such controls. Control is accomplished via control electronics, which adjust the torque produced by the electrical output generation device (e.g., alternator) within the wind turbine. During normal operation, torque is adjusted for optimum aerodynamic performance and maximum output of power. In winds above rated power, the control circuit regulates torque to lower aerodynamic performance, as necessary to maintain desired power level output. In triggering conditions, such as during simultaneous control circuit failure and loss of some portion of the electrical output generation device in extreme winds, wind turbine control is accomplished by increasing torque (e.g., via a separate controller) from the electrical output generation device via shorting of windings, so as to cause retardation of blade rotation.
Abstract:
Verfahren zur Auslaufsteuerung einer Asynchronmaschine (101), wobei während des Hochlaufens der Asynchronmaschine (101) aus dem Stillstand bis zur Betriebsdrehzahl der Wert einer Startenergie (E start ) bestimmt und gespeichert wird. Die Asynchronmaschine (101) wird im Reversierbetrieb mit einer Bremsenergie (E stop ) abgebremst, die der Startenergie (E start ) multipliziert mit einem Korrekturfaktor (δ) entspricht, wobei der Korrekturfaktor (δ) einen Wert zwischen 0 und 1 annimmt. Die Asynchronmaschine (101) wird durch DC-Bremsen nach erfolgtem Abbremsen im Reversierbetrieb weiter abgebremst.
Abstract:
A bandsaw including: a bandsaw blade; an AC electric motor driving the bandsaw blade via a coupling; a hazard detector which produces a hazard detection signal when a hazardous situation is detected; and a control circuit which drives the AC electric motor during normal operation and upon receiving a hazard detection signal causes the electric motor to be brought to a rapid stop by rapid DC injection braking.
Abstract:
An electrical machine comprising: at least one stator, at least one module, the at least one module comprising at least one electromagnetic coil and at least one switch, the at least one module being attached to the at least one stator; at least one rotor with a plurality of magnets attached to the at least one rotor, an integrated electrical differential coupled to at least one of the rotors, the at least one integrated electrical differential permitting the at least one rotor to output at least two rotational outputs to corresponding shafts, wherein the at least two rotational outputs are able to move the shafts at different rotational velocities to one another. The electrical machine is configured to fit into a housing, and that can be retrofitted into a conventional vehicle by replacing the mechanical differential.
Abstract:
The present invention relates to a softstarter (2) for starting and stopping an asynchronous motor (1) having three phases (L1, L2, L3), comprising two pairs (3A, 3C) of semiconductor devices of the type turning off at zero-crossing of the current therethrough, wherein each of said two pairs of semiconductor devices is connected in anti-parallel, and the first pair of the semiconductor devices is adapted to control the voltage of one of the phases of the motor and the second pair of the semiconductor devices being adapted to control the voltage of another of the phases of the motor, a DC reducing unit (16) associated with said two pairs (3A, 3C) of semiconductor devices for reducing a DC component in a load current of the said asynchronous three-phase motor during start of the motor, a first voltage measuring unit (8A, 8C) for measuring voltages across the two pairs of semiconductor devices, and a first zero-crossing detecting unit (14) configured for detecting zero-crossings of the measured voltages across the two pairs (3A, 3C) of semiconductor devices and providing zero-crossing signals (X1, X3) to the DC reducing unit.
Abstract:
The present disclosure relates to a motor drive unit (1) configured to operate a tap changer of an electromagnetic induction device. The motor drive unit (l) comprises an induction motor (M), a tap changer drive mechanism (5) arranged to be driven by the induction motor (M), and arranged to be mechanically coupled to a tap changer (5), and a rectifier (7). Braking operation of the motor drive unit (1) is obtained by means of the rectifier (7) which provides a DC current to the induction motor (M) to thereby obtain DC braking of the motor drive unit (1). The present disclosure also relates to an electromagnetic induction device and to a method of braking a motor drive unit (1).