CN2259678Y

CN2259678Y - Ring-shape small size current mutual inductor

Info

Publication number: CN2259678Y
Application number: CN 95244720
Authority: CN
Inventors: 侯雨生
Original assignee: SHANGHAI BEISITE INDUSTRY Co Ltd
Current assignee: SHANGHAI BEISITE INDUSTRY Co Ltd
Priority date: 1995-09-18
Filing date: 1995-09-18
Publication date: 1997-08-13
Anticipated expiration: 2005-09-18

Abstract

The utility model relates to a ring-shaped miniature current mutual inductor for detecting various AC electric appliances on an apparent current value. The utility model is characterized in that a winding in series wraps on an iron core which is wrapped by a perm alloy belt; an adjustable resistor R is in parallel connected at both ends of the winding. The utility model which has the advantages of convenient use, good electrical character, high accuracy of current conversion and high linearity can be directly welded on an electric control plate and used. The utility model is suitable for over current protection of various household appliances and medium-sized motors.

Description

Annular small current instrument transformer

The utility model relates to a kind of annular small current instrument transformer that is used to detect the apparent current value on the various ac electric apparatus.

At present; on sale on the market is the current transformer of the dual U-shaped iron core made by ferrite magnetic material; its weak point is to use the less current occasion; generally be used for detecting the electric current below 25 amperes; big electric current then easily produces magnetic saturation more than 25 amperes if surpass; therefore this current transformer is unwell to as drum type washing machine the overcurrent protection of floor air conditioner and various motors below 100 amperes etc.

The purpose of this utility model provides a kind of household electrical appliances and middle size motor to make the annular small current instrument transformer of overcurrent protection for overcoming the prior art shortcoming.

The technical solution of the utility model is achieved like this, and it is formed by sloping film alloy tape wrapping, and serial is wound with some circle coils on the iron core, is parallel with adjustable resistance R at the coil two ends.

Embodiment of the present utility model is described further in conjunction with the accompanying drawings.

Fig. 1 is annular small current instrument transformer structural representation;

Fig. 2 is the current transformer circuit graphical diagram of AC type output;

Fig. 3 is the current transformer circuit graphical diagram of once-through type output;

Fig. 4 is the typical circuit for the microcomputer input.

By shown in Figure 1,1, the iron core that forms of sloping film alloy tape wrapping, 2, be on the iron core serial coiling if in circle enameled wire loop L, 3, be the adjustable resistance R with coils from parallel connection of coils.The AC type output current transformer that has connected is installed in one and is of a size of in 25.4 * 12.7 * 29 millimeters the bakelite or plastic casing.Its circuit symbol as shown in Figure 2; the current transformer of this AC type output is suitable for the continuous change-detection of electric current of 1～100A scope; if will be to various electric equipments such as various household electrical appliance; as drum type washing machine, floor air conditioner; and the overcurrent protection of middle size motor; then as long as on the automatically controlled plate of these equipment, load onto this current transformer; output AC is output as direct voltage through rectification, filtering; this moment, current transformer was once-through type output; its circuit symbol is done protection to electric equipment under so easy realization specified current flow and is reported to the police as shown in Figure 3.Below lift a typical application example, in all kinds of air-conditionings, the compressor excess load, or move under the low pressure, or do the frequent moving operation that stops, and all can produce overcurrent, cause compressor damage.Current transformer provides a direct voltage to single-chip microcomputer as loading onto on the automatically controlled plate of air-conditioning, reaches 2.5V as this value.Often get the central value of 5V, mean that then compressor had reached flow valuve, then microcomputer promptly deals with warning, to avoid compressor damage.Its typical circuit as shown in Figure 4.Its adjustable resistance R decides according to the overcurrent value that claimed electric equipment output reaches 2.5V.The utility model is good through its electrical characteristic of evidence, coil D.C. resistance＜20 Ω, primary and secondary insulation resistance＞10 ⁹Ω, primary and secondary isolation voltage＞4000VDC.The current work frequency is measured with 50HZ, and operating frequency can expand to 400HZ, and the current conversion precision is 1%, has linear relationship.

The utility model characteristic structure is small-sized, and is easy to use, and electrical characteristic is good, current conversion The high good linearity of precision can directly be welded on electric control panel and be used, and is suitable for each household electrical appliance And the overcurrent protection of middle size motor.

Claims

1, a kind of annular small current instrument transformer of being made up of iron core and coil is characterized in that, serial is wound with coil on the iron core that it is formed by sloping film alloy tape wrapping, is parallel with adjustable resistance R at the coil two ends.