DD203439B1

DD203439B1 - CIRCUIT FOR BREAKING INDUCTION MOTORS

Info

Publication number: DD203439B1
Application number: DD23678382A
Authority: DD
Inventors: Ruediger Born; Hans-Joachim Mulorz; Wolfgang Hannemann
Original assignee: Rathenower Optische Werke Veb
Priority date: 1982-01-15
Filing date: 1982-01-15
Publication date: 1986-05-21
Also published as: DD203439A1

Description

-2- 367 83-2- 367 83

embodiment

Die Erfindung soll durch ein Ausführungsbeispiel unter Verwendung eines Schaltbildes näher erläutert werden.The invention will be explained in more detail by an embodiment using a circuit diagram.

Der beispielsweise in einem Schleifautomaten als Stellantrieb eingesetzte Induktionsmotor 3 ist mit seinen Feldwicklungen 6; 6' und 7; T sowie dem Phasenschieberkondensator 4 in bekannter Weise ans Netz angeschlossen und durch die Reihenschaltung des Widerstandes 1 und des Kondensators 2 entstört. Bei geschlossenem Motorschalter 5 wird der Kondensator 9 über den Widerstand 8 und die Diode 10 durch die Motorbetriebsspannung aufgeladen. Der Kondensator 17 wird alternierend über die Reihenschaltung Widerstand 13 und Diode 14 oder die Reihenschaltung Widerstand 15 und Diode 16 durch die negative und positive Halbwelle umgeladen.The used for example in an automatic grinding machine as an actuator induction motor 3 is with its field windings 6; 6 'and 7; T and the phase shifter capacitor 4 connected in a known manner to the mains and suppressed by the series connection of the resistor 1 and the capacitor 2. When the motor switch 5 is closed, the capacitor 9 is charged via the resistor 8 and the diode 10 by the motor operating voltage. The capacitor 17 is alternately transposed via the series circuit resistor 13 and diode 14 or the series circuit resistor 15 and diode 16 by the negative and positive half-wave.

Die Widerstände 13 und 15 sind so dimensioniert, daß am Verbindungspunkt 18 ein bezüglich der Thyristorsteuerelektrode negatives Potential liegt, wodurch die Diode 12 und der Thyristor 11 gesperrt werden.The resistors 13 and 15 are dimensioned so that at the connection point 18 with respect to the Thyristorsteuerelektrode negative potential, whereby the diode 12 and the thyristor 11 are blocked.

Wird der Motor 3 ausgeschaltet, d. h. der Motorschalter 5 wird geöffnet, so wird der Kondensator 17 nur noch durch die positive Halbwelle geladen, wodurch das Potential am Verbindungspunkt 18 positiv wird. Bei Erreichen der um die Flußspannung der Diode 12 aufgestockten Gate-Spannung zündet der Thyristor 11. Die auf dem Kondensator 10 gespeicherte Ladung durchfließt somit, begrenzt durch den Widerstand 8, die Hauptwicklung des Motors 3. Durch Induktion zwischen Hauptwicklung und Anker wird der Motor 3 gebremst. Die Bremszeit kann durch entsprechende Dimensionierung der Entladezeitkonstante für den Kondensator 9 optimiert werden.If the engine 3 is turned off, d. H. the motor switch 5 is opened, the capacitor 17 is charged only by the positive half cycle, whereby the potential at the connection point 18 is positive. Upon reaching the gate voltage boosted by the forward voltage of the diode 12, the thyristor 11 ignites. The charge stored on the capacitor 10 thus flows, limited by the resistor 8, through the main winding of the motor 3. By induction between the main winding and the armature the motor 3 braked. The braking time can be optimized by appropriate dimensioning of the discharge time constant for the capacitor 9.

Claims

367 83

Invention claim:

A circuit for braking induction motors using a series circuit of brake capacitor, thyristor and current limiting resistor arranged parallel to the motor winding and a diode connected in parallel with the thyristor, characterized in that a capacitor (17) having a pole at the cathode of the thyristor (11) and with the second pole connected to the anode of a cathode side connected to the control electrode of the thyristor (11) diode (12) and between Netzseitigem connection of the motor switch (5) and the connection point (18) between the diode (12) and capacitor (17) is a series circuit a resistor (15) and a diode (16) with the cathode at the connection point (18) is arranged, and between motorseitigem connection of the motor switch (5) and the connection point (18) between the diode (12) and capacitor (17) is a series circuit a resistor (13) and a diode (14) with the anode at the connection point (18) is arranged.

For this 1 page drawing

Field of application of the invention

The invention is applied to the deceleration of induction motors, in particular geared induction motors in such cases, where special emphasis must be placed on keeping the wake of the armature and its driven parts to a minimum after switching off the motor.

Characteristic of the known technical solutions

For field drives induction motors are used in most cases as a cost-effective variant. Due to the relatively high inertia of their armature such engines are not very suitable for equipment and facilities in which a caster after shutdown interferes. Ferrari engines are more suitable for such applications because of their lower mass inertia.

The known technical solutions, such. As specified in the patent DD 107553, operate on the principle of deceleration of the motor by reversing the phase sequence at the motor terminals or by applying DC to the motor. The disadvantage of such circuits is the relatively high circuit complexity. In most cases, a separate signal when turning off the engine on the brake circuit must be given here in addition, whereby an additional component cost is necessary.

Object of the invention

The aim of the invention is to find a safe working and effective braking device for induction motors with as few additional components that automatically acts when switching off the engine.

Explanation of the essence of the invention

Using the circuit complexity, a circuit should be specified for the tracking minimization, which reduces the susceptibility of the braking device with the least possible amount of components and thus increases the reliability.

Using a known DC braking, wherein the braking capacitor, which is charged during the engine operation via a diode, is switched when switching off the motor via a thyristor in series with a current limiting resistor to a winding of the motor, the solution of the object according to the invention is such that a Capacitor for establishing the Thyristorzündspannung between the thyristor cathode and the protected by a diode control electrode is connected. Between the connection point of the protective diode and the capacitor and the line-side terminal of the motor switch, a series circuit of a resistor and a lying with the cathode at the connection point diode is arranged and between the connection point and the motor-side terminal of the motor switch is a series connection of a resistor and one with the anode on Connection point lying diode arranged. Through the two series circuits of resistor and diode lying between the connection point and thyristor cathode capacitor is constantly reloaded during engine operation. After switching off the motor, the capacitor can only via the series circuit with the cathode side at the connection point, d. H. be charged to the capacitor, lying diode, so that the capacitor voltage reaches the increased by the forward voltage of the protection diode ignition voltage of the thyristor and switches this.