Split-type three-phase current mutual inductor interchange circuit

Abstract

The invention relates to an electromotor protection circuit, a pump-type protection circuit, a power capacitor protection circuit, a line protection circuit and the like, and aims to provide two kinds of split-type three-phase current mutual inductor interchange circuits. A split-type three-phase mutual inductor signal resistor is installed in a protector main shell; a signal shunting adjustable resistor is installed in a three-phase current mutual inductor shell; the signal shunting adjustable resistor is adjusted, so that the output of a split-type three-phase current mutual inductor has unified equal standard so as to interchange but not influence the accuracy. The circuit provided by the invention is simple and low in cost, has low requirements of connected and inserted elements, and is suitable for circuits of various split-type electromotor protectors, pump-type protectors, power capacitor protectors, line protectors and the like.

Description

technical field [0001] The invention relates to a motor protection circuit, a pump protection circuit, a power capacitor protection circuit, a line protection circuit, especially a split-type three-phase current transformer interchangeable circuit. Background technique [0002] At present, there are many types of motor protectors, pump protectors, power capacitor protectors, and line protectors, such as integrated and split. The integrated protector is the main shell of the protector, the display head and the three-phase current transformer. The split type is that the main shell of the protector, the display head and the three-phase current transformer are divided into two or three bodies, and the three-phase current transformer is installed separately. The problem is that the three-phase current transformers used for the protector are non-standard products with poor consistency. The precision of the integrated protector is adjusted by the circuit in the main shell of the pr...

AI Technical Summary

Problems solved by technology

The problem is that the three-phase current transformers used for the protector are non-standard products with poor consistency. The precision of the integrated protector is adjusted by the circuit in the main shell of the protector. The split type three-phase current transformers are all connected to the main shell of the protector. Body matching debugging can not be interchanged, if the main shell of a protector is replaced, it will cause a large error, and the proper protection effect cannot be achieved; in the shell of the split type three-phase current transformer, active amplification can be adopted to adjust the consistency, and there are problems It is the connecting line between the two bodies that adds two positive and negative power supply lines and an additional circuit for amplification, which increases the cost; the signal resistance can also be adjusted to achieve consistency in the shell of the split-type three-phase current transformer. The problem is that the current signal passes through the signal The output signal after the resistance is very small, and the contact resistance between the two bodies will seriously affect the protection accuracy if there is a slight bad contact of the plug socket.

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