Motor control circuit
By designing a motor control circuit including contactor, thermal relay and time relay, the problem of high temperature failure and difficult cooling time of the frequency converter is solved, and the normal operation and production efficiency of the motor are improved.
Patent Information
- Application Number
- CN202421690480.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-16
- Publication Date
- 2025-06-03
- Estimated Expiration
- 2034-07-16
AI Technical Summary
In industrial production, the frequency converter frequently fails due to high temperature operation, which affects the normal operation of the motor. Especially in hot and dry climates, the cooling time of the frequency converter is difficult to control, resulting in frequent failures or low production efficiency.
A motor control circuit is designed, including a contactor, thermal relay, first time relay, second time relay and intermediate relay. Through the series and parallel structures of these components, overheating failure cut-off and cooling time measurement of the inverter are realized to ensure the normal operation of the motor and avoid the problem of excessive or short cooling time.
The motor control circuit can ensure the motor's normal operation when the inverter overheating fault occurs, and prompt the operator to perform reset operations through the metering cooling time, avoiding the problems of frequent faults and low productivity, and improving work efficiency and production stability.
Smart Images
Figure CN222940727U_ABST
Abstract
Description
Technical Field:
[0001] The utility model relates to the technical field of motor control, and particularly to a motor control circuit. Background Art:
[0002] In industrial production, motors are often used together with frequency converters to achieve speed control of the motors. However, during the operation of the frequency converter, its internal components may operate at high temperatures, which may lead to failures and damages, affecting the operation of the entire system. In response to this, the frequency converter is internally equipped with an overheat relay. When the internal temperature of the frequency converter rises to a certain level, the thermistor will deform, causing the contacts to close. At this time, the overheat relay will cut off the power supply, stop the operation of the frequency converter, and simultaneously send an alarm signal to notify the operator for maintenance. At this time, the motor cannot operate due to power failure, affecting normal production. Especially in the hot and dry northwest region, and when the production operation site is an open-pit coal mine, due to the hot and dry climate, the frequency converter frequently experiences overheat failures, seriously affecting the production progress. And after maintenance, it needs to be naturally cooled before it can be put into use again. However, during the actual production operation process, the cooling time of the frequency converter is not regulated by the program, and it is generally manually operated by the staff. However, manual operation may result in too long or too short cooling time of the frequency converter, resulting in the frequency converter being shut down for a long time or being put into use before it is fully cooled, which will reduce the production efficiency of the crusher or cause the frequency converter to start at high temperature and increase the failure rate. Content of the Utility Model:
[0003] The purpose of the utility model is to provide a motor control circuit.
[0004] The utility model is implemented by the following technical solution: A motor control circuit includes a frequency converter connected between a power supply and a motor. It further includes a thermal relay, a contactor, a first time relay, a second time relay, and an intermediate relay. The main contacts of the contactor are connected in series with the thermal relay and then in parallel with the frequency converter. The coil of the contactor is connected in series with the normally closed contact of the thermal relay to form a first branch. The dry contact of the fault relay of the frequency converter is respectively connected in series with the first branch and the coil of the first time relay and then connected to the power supply. The energized-delay closing contact of the first time relay and the normally open contact of the intermediate relay are connected in parallel to form a third branch. The coil of the first time relay and the coil of the intermediate relay are connected in parallel to form a fourth branch. The energized-delay opening contact of the first time relay is successively connected in series with the third branch and the fourth branch and then connected to the power supply.
[0005] Further, it further includes an indicator light connected in parallel with the fourth branch.
[0006] Advantages of the present utility model: The main contacts of a contactor are provided in parallel with an inverter, and the contactor coil is connected in series with the normally open contact of the overheat relay of the inverter. When the inverter has an overheat fault, the main contacts of the contactor are closed, which can ensure that the motor is normally powered and running, and guarantees the working efficiency. Moreover, the first and second time relays are added to measure the cooling time of the inverter. After a certain period of cooling, the staff is prompted to perform a reset operation before the inverter can be put into use again, thereby avoiding frequent failures or low productivity caused by too long or too short cooling time of the inverter. Description of the drawings:
[0007] Figure 1 It is a schematic diagram of the overall structure of the present utility model.
[0008] Motor M, inverter BP, thermal relay FR, contactor KM, first time relay KT1, second time relay KT2, intermediate relay KA1, overheat relay FR1, indicator light HL. Specific implementation manners:
[0009] In the description of the present utility model, it should be noted that when terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. appear, the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present utility model. In addition, when terms such as "first", "second", "third" appear, they are only for descriptive purposes and cannot be understood as indicating or implying relative importance.
[0010] As Figure 1 shown, a motor control circuit includes an inverter BP connected between a power supply and a motor M. It further includes a thermal relay FR, a contactor KM, a first time relay KT1, a second time relay KT2, and an intermediate relay KA1. The main contacts of the contactor KM are connected in series with the thermal relay FR and then in parallel with the inverter BP. The coil of the contactor KM is connected in series with the normally closed contact of the thermal relay FR to form a first branch. The dry contacts of the fault relay KA2 of the inverter BP are respectively connected in series with the first branch and the coil of the first time relay KT1 and then connected to the power supply; the power-on delay closing contact of the first time relay KT1 and the normally open contact of the intermediate relay KA1 are connected in parallel to form a third branch. The coils of the first time relay KT2 and the intermediate relay KA1 are connected in parallel to form a fourth branch. The power-on delay opening contact of the first time relay KT2 is successively connected in series with the third branch and the fourth branch and then connected to the power supply; it further includes an indicator light HL connected in parallel with the fourth branch.
[0011] Control process:
[0012] Under normal circumstances, the dry contact of the fault relay KA2 is disconnected, and the start, stop and speed regulation of the motor M are controlled by the frequency converter BP.
[0013] When the inverter BP has an overheating fault, the overheating relay FR1 of the inverter BP cuts off the power supply of the motor M, and the dry contact of the fault relay KA2 is closed. At this time, the coil of the contactor KM is energized - the main contact of KM is closed - the motor M is energized and runs; at the same time, the coil of the first time relay KT1 is energized to start timing, and the cooling time of the inverter can be set through the first time relay KT1; when the preset time of the first time relay KT1 is reached, the power-on delay closing contact of the first time relay KT1 is closed - the coil of the intermediate relay KA1 is energized, forming a self-locking, and the indicator light HL lights up to remind the operator that the inverter BP can be reset, that is, the inverter BP can be started. When the inverter BP is started, the dry contact of the fault relay KA2 is disconnected, and the motor M is reset to the inverter BP control;
[0014] When the coil of the intermediate relay KA1 is energized, the coil of the second time relay KT2 is energized and timing starts. The lighting duration of HL1 can be set through the second time relay KT2. When the set time is reached, the power-on delay disconnection contact of the second time relay KT2 is disconnected.
[0015] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.
Claims
1. A motor control circuit, comprising a frequency converter (BP) connected between a power supply and a motor (M), characterized in that: It also includes a thermal relay (FR), a contactor (KM), a first time relay (KT1), a second time relay (KT2) and an intermediate relay (KA1). The main contact of the contactor (KM) is connected in series with the thermal relay (FR) and then connected in parallel with the frequency converter (BP). The coil of the contactor (KM) is connected in series with the normally closed contact of the thermal relay (FR) to form a first branch. The dry contact of the fault relay (KA2) of the frequency converter (BP) is connected in series with the first branch and the coil of the first time relay (KT1) respectively and then connected to a power supply. The power-on delay closing contact of the first time relay (KT1) and the normally open contact of the intermediate relay (KA1) are connected in parallel to form a third branch. The coil of the second time relay (KT2) and the coil of the intermediate relay (KA1) are connected in parallel to form a fourth branch. The power-on delay opening contact of the second time relay (KT2) is connected in series with the third branch and the fourth branch in sequence and then connected to the power supply.
2. A motor control circuit according to claim 1, characterized in that: It also includes an indicator light (HL) connected in parallel with the fourth branch.