Overload protector of single-phase AC motor

Abstract

The invention relates to a single phase ac motor over current protector in the field of compression refrigerating machine motor protector. It comprises a casing, a cover, an electric-heat wire, a double mental sheet, a fist hook, a second hook, a moving contact, a static contact, a fixed base and a trigger mechanism, wherein the static contact is fixed on the first hook; the electric-heat wire is fixed positioned inside the electric-heat wire channel by a pair of first and second column; the second column is connected with the second hook; the double mental sheet is disk type and positioned on the double mental sheet base upper to the electric-heat wire; the trigger mechanism comprises a top rod and a spring sheet; the top rod is positioned in the top rod hole of the fixed base; the top end and the low end of the double mental sheet are corresponding with the spring sheet; the fixed end of the spring sheet is fixed on spring sheet fixed base which is the lower part of the fixed base; the free end extents to the contact space-limit which is the channel lower part of the fixed base; the moving contact is fixed on the free end and is corresponding with the static contact.

Description

technical field [0001] The invention belongs to a motor protector of a refrigerating compressor, in particular to an overload protector capable of effectively protecting a single-phase AC motor from overtemperature and overload. Background technique [0002] As an overload protector for a single-phase AC motor, the currently more commonly used structure is shown in Figure 4, including a shell 1, a cover 2 for covering the shell 1, and a pair of shells extending to the shell 1. The first and second pins 5, 6, the heating wire 3, the bimetal 4, and the moving and static contacts a and b in the cavity and the other end is located outside the shell cavity of the housing 1, and the static contact b has a pair, One of the static contacts b is electrically connected to one end of the heating wire 3, the other end of the heating wire 3 is connected to the second pin 6, the other static contact b is in contact with the first pin 5, and the movable contact a has a pair. They are loca...

AI Technical Summary

Problems solved by technology

[0004] In the above six patent documents, CN2093438Y belongs to the embedded type, which is placed in the motor coil and cannot be repaired. Once the protective relay is damaged, it is often replaced together with the motor. Although there are only two contacts, the bimetal Cracking defects of the sheet and the defect that the bimetallic sheet participates in conduction as a resistance element in the conduction state of the circuit exist; CN2152301Y and CN2218263Y belong to the structural category described by the applicant in front of Figure 4, and all three defects exist; CN2287339Y is The technical scheme proposed by the applicant himself on October 23, 1996, first of all, since the spring sheet (the patent is called the spring arm) is in contact with the bimetal sheet, under normal working conditions, although the bimetal sheet does not act as a resistor The form of the element participates in conduction, but it is charged

Secondly, the ability of the bimetal sheet to sense temperature or accept heat radiation is poor, because the installation relationship between the protector of this structure and the motor prevents the bimetal sheet from being close to the surface of the motor casing, but in contact with the motor casing. Vertical, so the ability of the bimetal to receive the heat radiation of the motor is very lacking

In addition, the spring sheet and the heating wire (the patent is called heater) are prone to electrical short circuit, because the space between the heating wire and the bimetal is extremely small, and the mechanical shock resistance is extremely fragile in the production, assembly, transportation and other links, and it is easy to use The electrical gap between the two becomes smaller, and arcing often occurs when the circuit is in the conduction state during use, causing a short circuit. These defects are caused by the unreasonable distribution of the electrical structure; CN1207743C does not belong to the application field of refrigeration compressor motor protectors. And it can only be used for overheating protection, especially the above two defects also exist, the bimetal is easy to crack and participates in conduction as a resistance element; the lack of CN2341305Y is the same as the applicant's elaboration of CN2093438u

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