CN219811960U

CN219811960U - Overload protection circuit for motor

Info

Publication number: CN219811960U
Application number: CN202320865174.9U
Authority: CN
Inventors: 严宝强; 王彦彪; 王升; 秦海滨; 闫冬生
Original assignee: Inner Mongolia Yitai Guanglian Coalification Co ltd; Inner Mongolia Zhongyu Taide Coal Co ltd; Ordos Zhongyu Taide Coal Co ltd
Current assignee: Inner Mongolia Yitai Guanglian Coalification Co ltd; Inner Mongolia Zhongyu Taide Coal Co ltd; Ordos Zhongyu Taide Coal Co ltd
Priority date: 2023-04-17
Filing date: 2023-04-17
Publication date: 2023-10-10
Anticipated expiration: 2033-04-17

Abstract

The utility model discloses a motor overload protection circuit, which also comprises a current transformer TA and a current relay KI; the primary side of the current transformer TA is connected in series on any phase line of the main loop, and the secondary side of the current transformer TA is connected in series with a normally open contact of the time relay KT and a coil of the current relay KI to form a closed loop; the control loop comprises a normally closed contact, a normally closed button SB1, a normally open button SB2 and a coil of a contactor KM which are sequentially connected in series. The advantages are that: when another two-phase circuit without the current transformer TA is in a phase failure state, the phase current with the current transformer TA can rise immediately, the current monitored by the current transformer TA rises immediately to exceed a set value, the contactor KM coil is powered off, the main circuit power-off motor stops running, and an effective overload protection function is achieved on the motor.

Description

Overload protection circuit for motor

Technical field:

the utility model relates to the technical field of motor equipment, in particular to a motor overload protection circuit.

The background technology is as follows:

with the rapid development of the coal washing industry in China, a belt conveyor is required for conveying materials by a production system of a coal washing factory, and the belt conveyor is divided into belt frame installation, belt laying and vulcanizing of a belt joint after the belt is laid, or vulcanizing of the joint after the belt is torn and replaced; the belt tearing of coal washery takes place more frequently, leads to vulcanizing belt joint more frequently, and vulcanizer equipment must rise the temperature to 145 degrees celsius, even 160 degrees celsius, and the higher the temperature, the more electric current, and vulcanizer equipment load is also bigger, leads to the fact the motor overload to lead to the damage of motor easily.

The utility model comprises the following steps:

the utility model aims to provide a motor overload protection circuit capable of effectively realizing motor overload protection.

The utility model is implemented by the following technical scheme: the motor overload protection circuit comprises a main loop and a control loop, wherein the main loop is connected with an air switch QF and a normally open contact of a contactor KM in series; the current transformer is characterized by also comprising a current transformer TA and a current relay KI; the primary side of the current transformer TA is arranged on any phase line of the main loop, and the secondary side of the current transformer TA is connected with a normally open contact of the time relay KT and a coil of the current relay KI in series to form a closed loop; the coil of the current relay KI is connected in series with the normally open contact of the time relay KT and then connected in parallel with the normally closed contact of the time relay KT; the control loop comprises a normally closed contact, a normally closed button SB1, a normally open button SB2 and a coil of a contactor KM which are sequentially connected in series, wherein one normally open contact of the contactor KM is connected with the normally open button SB2 in parallel and is connected with a coil of a time relay KT in series, and the coil of the time relay KT is connected with the coil of the contactor KM in parallel.

Further, an alarm loop is connected in parallel to the control loop, the alarm loop comprises a series-connected intermediate relay KA coil and a normally open contact of the current relay KI, the normally open contact of the intermediate relay KA is connected in parallel with the normally open contact of the current relay KI, and the normally open contact of the intermediate relay KA is connected in series with an alarm.

The utility model has the advantages that: when another two-phase circuit without the current transformer TA is in a phase failure state, the phase current with the current transformer TA can rise immediately, the current monitored by the current transformer TA rises immediately to exceed a set value, the contactor KM coil is powered off, the main circuit is powered off, the motor stops running, and an effective overload protection effect is achieved on the motor.

Description of the drawings:

fig. 1 is a schematic diagram of a main circuit structure according to the present utility model.

Fig. 2 is a schematic diagram of the control loop and the alarm loop according to the present utility model.

The components in the drawings are marked as follows: main circuit 1, motor 1.1, control circuit 2, alarm circuit 3, alarm 3.1, air switch QF, contactor KM, current transformer TA, current relay KI, time relay KT, normally closed button SB1, normally open button SB2, intermediate relay KA.

The specific embodiment is as follows:

the following description of the embodiments of the present utility model will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

As shown in fig. 1 and 2, the present embodiment provides a motor overload protection circuit, which includes a main circuit 1 and a control circuit 2, wherein the main circuit 1 is connected in series with an air switch QF and a normally open contact of a contactor KM; it also includes a current transformer TA and a current relay KI; the primary side of the current transformer TA is arranged on any phase line of the main loop 1, and the function of additionally arranging the current transformer TA is to monitor the current of the main loop 1; the secondary side of the current transformer TA is connected with a normally open contact of the time relay KT and a coil of the current relay KI in series to form a closed loop; the coil of the current relay KI is connected in series with the normally open contact of the time relay KT and then connected in parallel with the normally closed contact of the time relay KT; the control loop 2 comprises a normally closed contact, a normally closed button SB1, a normally open button SB2 and a coil of a contactor KM of a current relay KI which are sequentially connected in series, wherein one normally open contact of the contactor KM is connected with the normally open button SB2 in parallel and is connected with a coil of a time relay KT in series, and the coil of the time relay KT is connected with the coil of the contactor KM in parallel.

Closing an air switch QF connected in series on a main loop 1 and an air switch QF on a control loop 2, pressing a normally open button SB2, powering up a coil of a contactor KM, closing a normally open contact of the contactor KM on the control loop 2, self-locking, closing a normally open contact of the contactor KM on the main loop 1, enabling a secondary current of a current transformer TA to pass through a normally closed contact of a time relay KT, starting a motor 1.1, starting timing the time relay KT, enabling the current of the motor 1.1 for 3-5 seconds just started to be 3-5 times of rated current, and setting the time relay KT to be 5 seconds in a time period called starting time, for example, the starting time is 5 seconds; after 5 seconds, the motor 1.1 is started, when the current is reduced to a normal range value, the normally closed contact of the time relay KT is opened, the normally open contact is closed, and the secondary current of the current transformer TA normally flows through the coil of the current relay KI.

When the secondary current of the current transformer TA exceeds the set current value of the current relay KI, the normally closed contact of the current relay KI on the control loop 2 is immediately disconnected, so that the coil of the contactor KM is powered off, the normally open contact of the contactor KM on the main loop 1 is disconnected, and the motor 1.1 stops running; when the other two-phase circuits on the main circuit 1, which are not provided with the current transformers TA, have a phase loss, the phase current provided with the current transformers TA can rise immediately, the current monitored by the current transformers TA rises immediately to exceed a set value, or the three-phase current exceeds the set value, the contactor KM coil is powered off, the main circuit 1 is powered off, the motor 1.1 stops running, and an effective overload protection effect is achieved on the motor 1.1.

The control loop 2 is connected with an alarm loop 3 in parallel, the alarm loop 3 comprises a normally open contact of a current relay KI and an intermediate relay KA coil which are connected in series, the normally open contact of the intermediate relay KA is connected with the normally open contact of the current relay KI in parallel, and the normally open contact of the intermediate relay KA is connected with an alarm 3.1 in series; when the normally closed contact of the current relay KI in the control loop 2 is opened, the normally open contact of the current relay KI is closed, the coil of the intermediate relay KA is electrified, the normally open contact of the intermediate relay KA is closed, and the alarm 3.1 is electrified to start alarming, so that a worker can definitely stop the overload of the motor 1.1 in time.

The foregoing description of the preferred embodiments of the utility model is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements that fall within the spirit and scope of the utility model.

Claims

1. The motor overload protection circuit comprises a main loop and a control loop, wherein the main loop is connected with an air switch QF and a normally open contact of a contactor KM in series; the current transformer is characterized by also comprising a current transformer TA and a current relay KI;

the primary side of the current transformer TA is arranged on any phase line of the main loop, and the secondary side of the current transformer TA is connected with a normally open contact of the time relay KT and a coil of the current relay KI in series to form a closed loop; the coil of the current relay KI is connected in series with the normally open contact of the time relay KT and then connected in parallel with the normally closed contact of the time relay KT;

the control loop comprises a normally closed contact, a normally closed button SB1, a normally open button SB2 and a coil of a contactor KM which are sequentially connected in series, wherein one normally open contact of the contactor KM is connected with the normally open button SB2 in parallel and is connected with a coil of a time relay KT in series, and the coil of the time relay KT is connected with the coil of the contactor KM in parallel.

2. The motor overload protection circuit according to claim 1, wherein an alarm circuit is connected in parallel to the control circuit, the alarm circuit comprises an intermediate relay KA coil and a normally open contact of the current relay KI which are connected in series, the normally open contact of the intermediate relay KA is connected in parallel with the normally open contact of the current relay KI, and the normally open contact of the intermediate relay KA is connected in series with an alarm.