JPS617294U

JPS617294U - Induction motor power switching device

Info

Publication number: JPS617294U
Application number: JP8132385U
Authority: JP
Inventors: 忠士市岡; 義一石島; 昭夫伊原
Original assignee: 株式会社明電舎
Priority date: 1985-05-30
Filing date: 1985-05-30
Publication date: 1986-01-17

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 drawings]

第１図は本考案の概略を示すブロック図、第２図は本考
案の一実施例を示す制御回路の結線図、第３図は説明の
ための波形図、第４図は切換え時のタイムチャート、第
５図は切換回路の構成図である。ＣＳはクッション回路、ＥＰは電源拾上げ検出回路、Ｐ
Ｐは速度検出器、ＣＣは制御回路。Fig. 1 is a block diagram showing an outline of the present invention, Fig. 2 is a wiring diagram of a control circuit showing an embodiment of the invention, Fig. 3 is a waveform diagram for explanation, and Fig. 4 is a timing diagram at the time of switching. The chart, FIG. 5, is a block diagram of the switching circuit. CS is a cushion circuit, EP is a power pickup detection circuit, P
P is a speed detector, CC is a control circuit.

Claims

[Scope of utility model registration request]

The induction motor is connected to a commercial power source and an inverter via a first changeover switch and a second changeover switch, respectively, and the drive power source for the induction motor is transferred from the commercial power source side to the inverter side having a setting device and a control circuit. The induction motor is operated by being switched on and off by turning on and off the first and second power supply changeover switches, the induction motor is provided with a speed detector, the control circuit for the inverter uses an integral circuit, and the power supply changeover signal is used to control the inverter. a cushion circuit comprising a first relay contact that shortens the time constant after a predetermined time after turning off the first changeover switch and returns the time constant to the original value when the output voltage of the inverter becomes a reference; A frequency-to-voltage converter that converts the output of the detector into a voltage signal, and a time constant shortened by the operation of the first relay contact and switching from the setting device side to the frequency-to-voltage converter side after a predetermined time; When the output voltage of the inverter reaches the reference value, a second relay contact switches from the frequency-to-voltage converter side to the setting device side again, and a switching element connects the output end of the amplifier to which the output of the setting device is input. Connected to the control side, the first cut-off switch is turned off by a power switching signal between the output terminal of this switching element and the input terminal of the amplifier, and is turned on when the rotational speed of the induction motor decreases to a set value. A switch element is connected, a discharge blocking diode and a capacitor are connected in series to the output terminal of this switch element, and a power pickup detection circuit takes out the output from the connection point of this capacitor and the diode, and the output of the cushion circuit is connected to the output terminal of the switch element. a circuit that controls the output frequency of the inverter based on the output frequency of the inverter and controls the voltage of the inverter based on a deviation signal obtained by comparing the output of the cushion circuit and the output of the power pickup detection circuit; A power supply switching device for an induction motor, wherein the second changeover switch is turned on while the output voltage value of the inverter is kept low.