DE935618C - Overcurrent protection device for control drives - Google Patents
Overcurrent protection device for control drivesInfo
- Publication number
- DE935618C DE935618C DES30679A DES0030679A DE935618C DE 935618 C DE935618 C DE 935618C DE S30679 A DES30679 A DE S30679A DE S0030679 A DES0030679 A DE S0030679A DE 935618 C DE935618 C DE 935618C
- Authority
- DE
- Germany
- Prior art keywords
- protection device
- overcurrent protection
- winding
- rotor voltage
- overcurrent
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/08—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors
- H02H7/085—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors against excessive load
Landscapes
- Protection Of Generators And Motors (AREA)
Description
Eine dauernde Drehzahlverminderung nicht fremdbelüfteter Schleifringläufermotoren durch Einschalten von Widerständen in den Läuferkreis ist nur bei Berücksichtigung der Verminderung des Nenndrehmomentes möglich. Wird in einem solchen Fall der Motor wie üblich nur durch einen Überstromselbstschalter geschützt, dessen Auslöser auf den Motornennstrom eingestellt ist, so kann bei herabgeregelter Drehzahl eine thermische Überlastung und damit eine Gefährdung des Motors erfolgen. Die thermische Überlastung birgt besonders im Hinblick auf die Verwendung derartig geregelter Motoren in explosionsgefährdeten Räumen große Gefahren in sich.A permanent reduction in the speed of non-force-ventilated slip-ring motors by switching on resistors in the rotor circuit is only taken into account the reduction of the nominal torque is possible. In such a case, the engine will as usual, only protected by an overcurrent circuit breaker, the release of which is on the rated motor current is set, a thermal Overload and thus endanger the engine. The thermal overload particularly with regard to the use of such regulated motors in potentially explosive areas Clear great dangers in themselves.
Zur Vermeidung dieser Nachteile geht die Erfindung von der Erkenntnis aus, daß ein einwandfreier Überstromschutz so arbeiten müß, daß sich die Ansprechgrenze der Überstromschutzeinrichtung mit dem Drehmoment proportional ändert. Es sind deshalb gemäß der Erfindung besondere Mittel an der Überstromschutzeinrichtung für derartige Regelantriebe vorgesehen, durch die die Ansprechgrenze der Überstromschutzeinrichtung proportional oder annähernd proportional mit -der Drehzahl geändert wird, wofür als Maßstab die Änderung der Läuferspannung dient. Zum Beispiel kann ein Bimetallrelais mit zwei Wicklungen verwendet werden, dessen eine Wicklung vom Ständerstrom des Motors durchflossen und dessen andere Wicklung, insbesondere als Zusatzwicklung, an die Läuferspannung angeschlossen .wird.To avoid these disadvantages, the invention is based on knowledge from the fact that a faultless overcurrent protection must work in such a way that the response limit the overcurrent protection device changes proportionally with the torque. It is therefore according to the invention special means on the overcurrent protection device for such Control drives provided through which the response limit of the overcurrent protection device is changed proportionally or approximately proportionally with the speed, for which purpose the change in the rotor voltage serves as a benchmark. For example, a bimetal relay can be used with two windings, one winding of which depends on the stator current of the Motor flows through and its other winding, especially as an additional winding, connected to the rotor voltage.
Zur Anpassung der Kennlinie der Überstromschutzeinrichtung an die Erwärmungscharakteristik des Motors sind dabei im Stromkreis der Zusatzwicklung Widerstände, vorzugsweise Heißleiterwiderstände entsprechender Charakteristik, angebracht.To adapt the characteristic curve of the overcurrent protection device to the The heating characteristics of the motor are in the circuit of the additional winding Resistors, preferably thermistor resistors of appropriate characteristics, attached.
An Hand der Zeichnung ist ein Ausführungsbeispiel näher erläutert.An exemplary embodiment is explained in more detail using the drawing.
An ein Drehstromnetz r ist über -einen Selbstschalter 2 ein Asynchronmotor mit Schleif ringläufer 3 angeschlossen. In dem Magnetspulenstromkreis des Schalters 2 liegt eine Unterbrechungsstelle q., die von einer Überstromschutzeinrichtung 5 betätigt wird. Diese Überstromschutzeinrichtung besteht aus einem Bimetallstreifen 6 mit zwei Wicklungen 7 und 8; die Wicklung 7 wird von, einem dem Motorstrom proportionalen Strom, z. B. dem Sekundärstrom eines Stromwandlers. g, gespeist; die Wicklung 8 liegt über einen Vorschaltwiderstand ro an der Läuferspannung des Motors 2.An asynchronous motor is connected to a three-phase network r via a circuit breaker 2 connected with slip ring traveler 3. In the switch solenoid circuit 2 is an interruption point q., Which is controlled by an overcurrent protection device 5 is operated. This overcurrent protection device consists of a bimetal strip 6 with two windings 7 and 8; the winding 7 is of a proportional to the motor current Electricity, e.g. B. the secondary current of a current transformer. g, fed; the winding 8 is connected to the rotor voltage of motor 2 via a series resistor ro.
Eine andere Lösung des Erfindungsgedankens besteht darin, daß die Zusatzspule nicht unmittelbar auf den Bimetallstreifen, sondern auf den Gegenkontakt der Unterbrechungsstelle q. magnetisch einwirkt, indem j e nach der Läuferspannung der Gegenkontakt verschoben und damit die Kontaktgabe verändert wird.Another solution to the inventive concept is that the Additional coil not directly on the bimetallic strip, but on the mating contact the interruption point q. acts magnetically by depending on the rotor voltage the mating contact is shifted and thus the contact is changed.
Claims (3)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DES30679A DE935618C (en) | 1952-10-17 | 1952-10-17 | Overcurrent protection device for control drives |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DES30679A DE935618C (en) | 1952-10-17 | 1952-10-17 | Overcurrent protection device for control drives |
Publications (1)
Publication Number | Publication Date |
---|---|
DE935618C true DE935618C (en) | 1955-11-24 |
Family
ID=7480234
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
DES30679A Expired DE935618C (en) | 1952-10-17 | 1952-10-17 | Overcurrent protection device for control drives |
Country Status (1)
Country | Link |
---|---|
DE (1) | DE935618C (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1079171B (en) * | 1958-12-12 | 1960-04-07 | Mauz & Pfeiffer | Overcurrent protection circuit with thermal release for speed-controlled electric motors |
DE1109771B (en) * | 1958-03-12 | 1961-06-29 | Licentia Gmbh | Starting relay for single-phase induction motors |
DE1117707B (en) * | 1959-06-25 | 1961-11-23 | Siemens Ag | Arrangement for monitoring the start-up of electrical machines |
-
1952
- 1952-10-17 DE DES30679A patent/DE935618C/en not_active Expired
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1109771B (en) * | 1958-03-12 | 1961-06-29 | Licentia Gmbh | Starting relay for single-phase induction motors |
DE1079171B (en) * | 1958-12-12 | 1960-04-07 | Mauz & Pfeiffer | Overcurrent protection circuit with thermal release for speed-controlled electric motors |
DE1117707B (en) * | 1959-06-25 | 1961-11-23 | Siemens Ag | Arrangement for monitoring the start-up of electrical machines |
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