Current transformer
The utility model relates to a kind of current transformer, is used in the intelligent circuit breaker (hereinafter to be referred as " intelligent switch ") of big current specification, and it is inserted on the copper bus-bar of " intelligent switch ", for " intelligent switch " provides working power and current detection signal.
Common current transformer is a kind of electromagnetic device that is used to measure electric current, is to utilize input winding on the iron core and output current ratio and the inversely proportional principle of turn ratio between winding to be made.This current transformer is not suitable for being applied on " intelligent switch ".China's utility model patent 99203287.3, a kind of " quick-magnetic saturated current transformer " that can be applied on " intelligent switch " disclosed, it is the magnetic shunt piece that changes with the permeability magnetic material thin slice of the other insertion of output winding wire bag (being the energy coil) at annular core, the magnetic shunt piece can bypass a part of magnetic line of force by the energy coil when big electric current, thereby the short circuit current of energy coil is remained unchanged substantially, reach the purpose of current limliting, and then solved " intelligent switch " the power supply stability under big electric current and the difficult problem of heating.But, above-mentioned patent is because the existence of magnetic shunt piece, make current transformer have following defective: at first, the magnetic shunt piece makes magnetic circuit that variation take place, influenced the magnetic circuit of measuring in the coil and distributed, made the poor linearity of the output signal of measuring coil, especially when big electric current, three alternate three consistency of measuring coil are relatively poor, and interference is arranged mutually; Secondly, because the requirement of the gap between magnetic shunt piece and the annular core is comparatively strict, therefore installs and adjust inconvenience; Once more, when the electric current I 〉=1.2In that flows through in the copper bus-bar (rated current), the short circuit current that installs the magnetic shunt piece additional is also enough not little.
The purpose of this utility model be to provide a kind of rational in infrastructure, easy for installation, short circuit current is little, can efficiently solve energy coil power supply stability and heating problem under big electric current and make the good current transformer of linearity of output signal of measuring coil.
The purpose of this utility model is achieved like this, a kind of current transformer, it is by housing 8, be located at the measurement coil 11 in the housing 8, insulation cushion 12, annular core 1, the mutual inductor 3 that is placed on the annular core 1 by bobbin 2 reaches the current-limiting components composition of connecting with mutual inductor 3, described current-limiting components is a current-limiting inductor 14, current-limiting inductor 14 is wound on the hollow skeleton 13 and is positioned at housing 8, the outside of annular core 1, the one terminals are connected with terminals of mutual inductor 3, another terminals are connected with plug 5 by lead, another terminals of mutual inductor 3 are connected with plug 5 by lead, and two terminals measuring coil 11 are connected with plug 6 by lead respectively.
The utility model is to divide two parts coiling with the energy coil, and wherein a part is wound on the annular core 1, claims mutual inductor 3, and another part is wound on the hollow skeleton 13, claims current-limiting inductor 14, and then two parts coil is together in series.Behind this novel employing said structure, both solved power supply stability and the heating problem of electric current mutual inductor under big electric current, reduced the energy coil again to measuring the influence of coil, make that the linearity of output signal of measuring coil is good, particularly when big electric current, three alternate three consistency of measuring coils have been guaranteed.
Below in conjunction with accompanying drawing the utility model body is further narrated.
Accompanying drawing is a structure diagram of the present utility model.
The housing 8 general plastic mouldings that adopt of the present utility model form, and the bottom centre of housing 8 has a base 10, and the centre of base 10 is through holes, is copper bus-bar jack 9, is used for the copper bus-bar of plant " intelligent switch ".Place below in the bottom of housing 8 and to measure coil 11, two terminals measuring coil 11 are connected with plug 6 respectively, simultaneously, for the ease of connecting and installing, can set up one and print copper-clad plate 4, be laid with some printed conductors printing in the copper-clad plate 4, two terminals at first will measuring coil 11 are connected with two printed conductors in the printing copper-clad plate 4 respectively, two printed conductors are connected with plug 6 by lead again, and print copper-clad plate 4 by screw on the boss 7 of housing 8.The utility model is provided with an insulation cushion 12 above measurement coil 11, above insulation cushion 12, be placed with annular core 1 and with the current-limiting inductor 14 of hollow skeleton 13, wherein annular core 1 is nested with on base 10, current-limiting inductor 14 is positioned at the outside of annular core 1, penetrating a mutual inductor 3 that is wound in enamelled wire on the bobbin 2 on the annular core 1, terminals of mutual inductor 3 are connected in series with terminals of current-limiting inductor 14, another terminals of mutual inductor 3 are connected on the printed conductor printing copper-clad plate 4, this printed conductor is connected with plug 5 by lead again, another terminals of current-limiting inductor 14 then are connected on another root printed conductor of printing copper-clad plate 4, and this printed conductor is connected with plug 5 by lead again.Through the above-mentioned current transformer that assembles in the upper end of housing 8 again with resin or silicon rubber embedding, plug 5,6 is exposed to outside the housing 8.
The utility model only needs current transformer is inserted on the copper bus-bar of " intelligent switch " by the copper bus-bar jack 9 on its base 10 when mounted, and plug 5,6 is connected with the control circuit of " intelligent switch " respectively gets final product, and installs very convenient.