DD262953A1

DD262953A1 - CIRCUIT ARRANGEMENT FOR CURRENT BRAKING OF ROTARY CURRENT MOTORS, PARTICULARLY OF CIRCULAR DOSING PUMPS

Info

Publication number: DD262953A1
Application number: DD30585987A
Authority: DD
Inventors: Dietrich Ferchland; Wolfgang Graefe; Wolfgang Schroeder; Herbert Wirkner
Original assignee: Forsch Rationalisierung Lacke
Priority date: 1987-08-10
Filing date: 1987-08-10
Publication date: 1988-12-14

Abstract

Drehstrommotore von Kreiseldosierpumpen von foerderstromgesteuerten Abfuellanlagen koennen auch ohne ein Zeitrelais, dass die Dauer des ueber einen Bremsschutz auf den Antriebsmotor zu seiner Abbremsung gelegten Gegenstrom sonst einzustellen haette, abgebremst werden. Erfindungsgemaess ist bei Drehstrommotoren bis zu maximal 250 Watt und mit bis zu maximal 1 400 min 1 Umdrehungen die Zeitdifferenz, die nach dem Abschalten eines Betriebsschuetzes durch die Schalttraegheit eines neutralen Relais und des Bremsschuetzes resultiert, bis das letztere auch abschaltet, fuer das Abbremsen allein ueberraschend gut geeignet.Three-phase motors of Kreiseldosierpumpen of delivery-controlled filling systems can be braked without a time relay that would otherwise have to adjust the duration of the counter-current applied to the drive motor for its deceleration via a brake protection. According to the invention is in three-phase motors up to a maximum of 250 watts and up to a maximum of 1 400 min 1 turns the time difference that results after switching off a Betriebsschuetzes by the Schalttregheit a neutral relay and the Bremsschuetzes until the latter shuts down, for braking alone surprising well suited.

Description

Erfinderisch wurde also überraschend gefunden, daß in der angewendeten Schaltungsanordnung die Kombination „Neutrales Relais/Sremsschütz" bei der oben charakterisierten Klasse der leistungsschwächeren Drehstrommotore zusätzlich zu ihrer eigentlichen Abschaltfunktion die der Zeitverzögerung der Abschaltung des Bremsstromes, also eines Zeitgliedes, im Millisekunden bereich, übernimmtInventively, it was surprisingly found that in the applied circuit arrangement, the combination "neutral relay / Sremsschütz" in the above-characterized class of low-power three-phase motors in addition to their actual shutdown the time delay of the shutdown of the braking current, ie a timer, in the millisecond range, takes over

Die Erfindung wird im anschließenden Ausführungsbeispiel näher erläutert. The invention will be explained in more detail in the following embodiment.

embodiment

In der zugehörigen Zeichnung bedeutenIn the accompanying drawing

Figur 1: HauptstromteilFigure 1: Main flow part

Figur 2: Nebenstromteil (Steuerung)Figure 2: Secondary flow part (control)

Im einzelnen arbeitet die Schaltungsanordnung nach Figur 1 und Figur 2 wie folgt:In detail, the circuit arrangement of Figure 1 and Figure 2 operates as follows:

Der Anlaufbefehl 6 schaltet über eine programmierte Laufzeitsteuerung 7 das Betriebsschütz 2 ein und der Drehstrommotor 5, welcher eine Leistung bis maximal 250 Watt und eine maximale Drehzahl von 1400 min"¹ aufweist, läuft an (Füllvorgang). Über einen Schließer 8 des Betriebsschützes 2 wird das neutrale Relais 9 aktiviert, das über einen Schließer 10 das Bremsschütz 1 einschaltet und somit für die Bremsung vorbereitet.The start command 6 turns on a programmed run time controller 7, the operating contactor 2 and the AC motor 5 having a power up to a maximum of 250 watts and a maximum rotational speed of 1400 min ^"1, running on (filling process). About a shutter 8 of the operating contactor 2 activates the neutral relay 9, which turns on a closer 10, the brake contactor 1 and thus prepared for braking.

Die programmierte Füllbeendigung schaltet das Betriebsschütz 2 ab und seine Leistungskontakte 4 schalten in Öffnerstellung.The programmed filling completion switches off the contactor 2 and its power contacts 4 switch to the normally closed position.

Wenn das neutrale Relais 9 und das Bremsschütz 1 typbedingt nacheinander bezogen auf das ihnen vorgeschaltete Betriebsschütz 2 innerhalb von Millisekunden verzögert abschalten, also für die Schaltung des Bremsstromes noch kurzzeitig aktiviert sind, werden die Hauptstrompfade für einen solchen Strom mit entgegengerichtetem Drehsinn über den Kontaktsatz 3 des noch angezogenen Schützes 1 und den Kontaktsatz 4 des bereits abgefallenen Schützes 2 geschlossen, wodurch die Bremsung durch Gegenstrom bewirkt wird. Die im Millisekundenbereich sequentiell abfallenden Relais 9 und Bremsschütz 1 trennen abschließend den Motor wieder vom Netz.If the neutral relay 9 and the brake contactor 1 by type delayed successively based on the upstream them contactor 2 within milliseconds switch off, are still activated for a short time for the circuit of the braking current, the main current paths for such a current with opposite directions of rotation on the contact set 3 of Still attracted contactor 1 and the contact set 4 of the already dropped contactor 2 is closed, causing the braking by countercurrent. The relays 9 and brake contactor 1, which drop sequentially in the millisecond range, finally disconnect the motor from the mains.

Ein Weiterdrehen des Motors in Förderrichtung oder in entgegengesetzter Richtung bis zu einer Drehzahl, die den Förderstrom der Dosierpumpe bewirken würde, läßt sich damit sicher unterbinden.A further rotation of the motor in the conveying direction or in the opposite direction up to a speed which would cause the flow of the metering pump can thus be safely prevented.

Claims

Circuit arrangement for countercurrent braking of three-phase motors by phase change in particular for centrifugal pumps with a maximum power of 250 watts at speeds of 1400 min " ¹ , characterized in that an operating contactor (2), which is turned on, via a normally open (8) a neutral relay ( 9) is activated, which in turn via a closer (10) turns on a brake contactor (1) is applied to the phase-reversed rotary voltage for counter-current braking, which is effective as a braking current of the drive motor when the contactor (2) is turned off, and stops as long as the type-related switching inertia of the neutral relay (9) and the brake contactor (1) makes.

For this 1 page drawings

Field of application of the invention

The invention relates to a circuit arrangement for counter-current braking of three-phase motors up to a maximum of 250 watts at speeds of maximum 1400min " ^1. Such electromotive drives can be used, for example, as a delivery drive of rotary metering pumps in filling, but their application is not limited thereto.

Characteristic of the known state of the art

It is known that three-phase motor can be braked vigorously by interchanging two phase connections. The problem here is to dose the phase-reversed braking current correctly. In principle, only the switching time of the braking current, ie the braking time, is available as a variable for this purpose. In certain cases it is particularly important to bring the engine to a standstill exactly.

However, under the influence of the phase-reversed "braking current", the speed of the motor η = 0 causes it to reverse in the opposite direction, unless this is prevented by additional technical measures, such as the brake monitor, in other cases, such as in the case of the fan-driven conveying drive of Liquids, above all, the safe and fast adjustment of the conveyor current ineffective speed range of the engine by braking is essential.

A very slow run-down or restart in the opposite direction is irrelevant. In the case of three-phase motors of low power, as it corresponds to motors up to 250 watts and a realizable speed up to 1400 min " ¹ , the absolute amount of the applied braking current fuse technology with known means manageable, the relatively high braking current amount is only in engines with higher Thus, there is no problem in giving the braking current instantaneously undiminished effect on the motor. Both low-power three-phase motors have the disadvantage of the known state of the art, above all in that with the known means, in particular by switching the brake current time the braking contactor of a conveying stream drive motor by an RC element, the remaining of the engine speed in the flow-ineffective area without stronger restart in the opposite direction can not be effected (see, inter alia, DE 2630866, DD 44293, DD 15185 or DD 106511).

Object of the invention

The aim of the invention is to stop the flow of the three-phase motors of rotary metering pumps of filling devices in a dosing manner.

Essence of the invention

The object of the invention is to decelerate the current three-phase motor of a delivery-current drive of a rotary metering pump to a delivery-inoperative speed within milliseconds.

The object is achieved in that an operating contactor 2, which is turned on, via a closer 8, a neutral relay 9 is activated, which in turn via a closer 10, a brake contactor 1 turns on. This ensures that at the brake contactor compared to the conveyor drive in two phases interchanged three-phase voltage is applied, which is effective immediately as a braking current of the delivery current drive motor when the service contactor 2 is turned off due to the programmed filling end of the filling device.

The shutdown of the contactor 2 has the shutdown of the neutral relay 9 and this process turn the shutdown of the brake contactor 1, which separates the phase-reversed voltage for braking from the drive motor, the result. The engine is then no longer braked. In this case, by the switching inertia of the neutral relay and the downstream brake contactor in the millisecond range between the shutdown of the operating contactor and the brake contactor surprisingly to reduce the speed of three-phase motors of the power up to 250 watts and a realizable speed of 1400 min " ¹ in the flow ineffective Area sufficient braking time causes, so long enough a phased brake current passed through, without the drive motor in the opposite direction of rotation noticeably starts again.