JPS58143433U

JPS58143433U - motor protection relay

Info

Publication number: JPS58143433U
Application number: JP3931782U
Authority: JP
Inventors: 正己榊原
Original assignee: 三菱電機株式会社
Priority date: 1982-03-19
Filing date: 1982-03-19
Publication date: 1983-09-27

Abstract

(57)【要約】本公報は電子出願前の出願データであるた
め要約のデータは記録されません。(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Brief explanation of the drawing]

第１図は従来のモータ保護継電器の概略構成を示すブロ
ック図、第２図は本考案に係るモータ保護継電器の概略
構成を示すブロック図である。各図中、同一部材には同一符号を付し、１０は変流器、
１２は過電流検出回路、１４は不平衡率判定回路、１４
ａは起動時不平衡率判定回路、１４ｂは運転時不平衡率
判定回路、１６は時間設定回路、２０はリレー回路、１
Ｂはオア回路、２２はアンド回路、２４はノット回路で
ある。FIG. 1 is a block diagram showing a schematic structure of a conventional motor protection relay, and FIG. 2 is a block diagram showing a schematic structure of a motor protection relay according to the present invention. In each figure, the same members are given the same symbols, and 10 is a current transformer;
12 is an overcurrent detection circuit, 14 is an unbalance rate determination circuit, 14
a is a startup unbalance rate determination circuit, 14b is an operation unbalance rate determination circuit, 16 is a time setting circuit, 20 is a relay circuit, 1
B is an OR circuit, 22 is an AND circuit, and 24 is a NOT circuit.

Claims

[Scope of utility model registration request]

(1) Load on three-phase motor main circuit! a current transformer that detects the current; and an unbalance rate determination circuit that calculates the unbalance rate of the load current detected by the current transformer and outputs an unbalance signal when the unbalance rate exceeds a set reference value. , an overcurrent detection circuit that outputs an overcurrent signal when the load current detected by the current transformer exceeds a set reference value; and an overcurrent detection circuit that outputs an activation signal when the overcurrent signal is continuously output for a predetermined time. and a relay circuit that opens the main circuit when at least one of the unbalanced signal and the actuation signal is input, while the overcurrent signal is being output. A motor protection relay characterized in that a set reference value of the balance rate determination circuit is set high, and a set reference value of the unbalance rate determination circuit is set low while the overcurrent signal is stopped.

(2) Scope of Utility Model Registration Claim (1) In the motor protection relay described in (1), the unbalance rate determination circuit includes a startup unbalance rate determination circuit with a high set standard value and an operation time with a low set standard value. When the overcurrent detection circuit is outputting an overcurrent signal, the unbalance rate of the load current is determined by the startup unbalance rate judgment circuit, and when the overcurrent detection circuit is stopping the overcurrent signal, A motor protection relay characterized in that each judgment is made by an unbalance rate judgment circuit during operation.