CN201887450U

CN201887450U - Current-limiting adjustable protector circuit for AC circuit

Info

Publication number: CN201887450U
Application number: CN201020561758XU
Authority: CN
Inventors: 周茜
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-10-03
Filing date: 2010-10-03
Publication date: 2011-06-29
Anticipated expiration: 2020-10-03

Abstract

The utility model relates to a circuit protection device ensuring that the current in an AC circuit does not exceed a normal working current range. Particularly, the device comprises a transformer, a rectifier, a triode transistor, a capacitor and a relay electrically connected as pictured, so as to realize the functions of automatic switching of two circuits and circuit exchange, and realize an adjustable rated current. The connection characteristic of the circuit is that the device provided by the utility model has no series connection, small power consumption, and no influence on a load circuit. The conversion relation between current and electromagnetism can be utilized, when a rated current is adjusted, the load circuit is automatically cut off by the automatic switch if a heavy-current exceeding the rated current appears in the circuit, so as to protect the circuit; and when the risks are eliminated, the circuit is recovered automatically.

Description

The alternating current circuit current limliting is adjustable protector circuit

Technical field

The utility model system guarantees that about a kind of electric current in the alternating current circuit is no more than the circuit brake of set running current scope; particularly this device has been realized the function of two circuit automatic switch and the effect of changing the road by transformer, rectifier, transistor, electric capacity, relay by electric connection mode as shown in Figure 1, and has realized the function of adjustable rated current.The connection characteristics of circuit are that the utility model device and load are not connected, and power consumption is little, and load circuit is not had influence.He is a relation of having utilized electric current and electromagnetic conversion, after setting up a rated current, if when occurring surpassing the big electric current of rated current in the circuit; automatic switch cuts off load circuit automatically; realization is to the protective effect of circuit, if the front end power up is normal, it is normal that circuit also will recover automatically.

Background technology

At present, be extensive use of thermal relay, the present invention is different fully on attribute and principle with it.Its circuit more complicated and non-adjustable of other protector.

Summary of the invention

The adjustable protector circuit of a kind of alternating current circuit current limliting, it has at least two secondary winding series connection backs to connect with load with the parallel connection of rectifier input and one of them secondary winding to comprise a transformer; Its coil of one relay is connected with the collection emitter-base bandgap grading of transistor again at least with after the electric capacity parallel connection; It is to be connected between the base stage and collector electrode of transistor to a potentiometer at least as variable resistor; It links to each other the normally opened contact of one relay with the primary coil of transformer and normally-closed contact links to each other with output at least.

A termination power N line after the primary winding coil is connected with the normally opened contact of relay, the other end is connected with the L line of power supply; An end connects the L line of power supply after the less transformer secondary output windings in series of normally-closed contact and number of turn, the other end connects the L line end of load, and the input that is connected respectively to a bridge rectifier of forming by four diodes after two secondary winding series connection of transformer; One end of the positive pole of electrochemical capacitor and relay coil is parallel to the f point and is connected on the positive pole of bridge rectifier output, the negative pole of electric capacity and the other end of relay coil are parallel to the g point; Potentiometer one end be connected in the g point, the other end links to each other with the base stage of transistor T, transistorized collector electrode is connected on the g point, the negative pole of emitter crossover formula rectification output.As shown in Figure 1.Relay normally open contact when normally-closed contact disconnecting consumers circuit again moment connect 220 volts of power supplys to the transformer primary winding, inferior limit induced electromotive force is designed to the pick-up voltage of relay coil.

Description of drawings

The elementary winding of 1,2 indication transformers in Fig. 1 alternating current circuit current limliting the is adjustable protector circuit, rated voltage is 220V; 3,4 expression secondary winding, about 2 to 3 volts of rated voltage; 5,6 another secondary winding of expression, about 6 volts of rated voltage.

Embodiment

Choosing one limit has two windings and induced potential to be respectively 6 volts and 3 volts transformer, a relay, a potentiometer, an electrochemical capacitor and a transistor, a termination power N line after the primary winding coil is connected with the normally opened contact of relay, the other end is connected with the L line of power supply; An end connects the L line of power supply after the less transformer secondary output windings in series of normally-closed contact and number of turn, and the other end connects the L line end of load; And the input that is connected respectively to a bridge rectifier of forming by four diodes after two secondary winding series connection of transformer; One end of the positive pole of electrochemical capacitor and relay coil is parallel to the f point and is connected on the positive pole of bridge rectifier output, the negative pole of electric capacity and the other end of relay coil are parallel to the g point; Potentiometer one end be connected in the g point, the other end links to each other with the base stage of transistor T, transistorized collector electrode is connected on the g point, the negative pole of emitter crossover formula rectification output end.As shown in Figure 1.

Primary winding, rated voltage are 220V; The rated voltage of two secondary winding is respectively 3 volts and 6 volts; Potentiometer choosing less than 1K all can, electric capacity is got 25V.1000UF, the transistor model is 3DD15D, the relay model is TRU-12VDC-SB-CL.

Claims

1. adjustable protector circuit of alternating current circuit current limliting, it has at least two secondary winding series connection backs to connect with load with the parallel connection of rectifier input and one of them secondary winding to comprise a transformer; Its coil of one relay is connected with the collection emitter-base bandgap grading of transistor again at least with after the electric capacity parallel connection; It is to be connected between the base stage and collector electrode of transistor to a potentiometer at least as variable resistor; It links to each other the normally opened contact of one relay with the primary coil of transformer and normally-closed contact links to each other with output at least.

2. it is characterized in that according to the adjustable protector circuit of the described alternating current circuit current limliting of claim 1: transformer coil time limit induced electromotive force is designed to the pick-up voltage of relay coil.