Air compressor starting control circuit

Abstract

The utility model discloses an air compressor starting control circuit which comprises a main contactor, an angle type contactor, a Y type contactor, a thermal relay and a circuit breaker, and a pressure sensor is arranged on an air tank. The air compressor control circuit has the advantages that the second time relay is additionally arranged in the circuit and used for setting the running time of important equipment, in the running process of the important equipment, a coil of the second time relay is always powered on for timing, a normally-closed contact of the second time relay disconnects the air compressor control main circuit, and then the problem that the voltage is unstable when the air compressor is started when the important equipment runs can be solved; and important equipment can operate stably. The circuit has a manual control mode and an automatic control mode, can be manually controlled, and can also be automatically controlled according to the detection of the pressure sensor.

Description

Technical Field:

[0001] The utility model relates to the technical field of air compressor control, and particularly relates to a starting control circuit for an air compressor. Background Art:

[0002] An air compressor is a commonly used device in production enterprises. Its main function is to compress air and then store it in an air tank for various instruments in the production system to use as instrument air. When the instrument air in the air tank is insufficient, the air compressor is started to compress air, and when the storage capacity of the compressed air is reached, the air compressor stops running. Usually, the air compressor shares the power supply with various equipment in the production enterprise, and the air compressor usually adopts a step-down circuit composed of a main contactor KM1, a delta contactor KM2, a star contactor KM3, a thermal relay FR, and a circuit breaker QF to achieve step-down starting. However, during the frequent start and stop of the air compressor, the step-down starting method it adopts often pulls down the small-range grid voltage and affects the normal use of important electrical equipment in the enterprise. Content of the Utility Model:

[0003] The purpose of the utility model is to provide a starting control circuit for an air compressor

[0004] The utility model is implemented by the following technical solution: An air compressor starting control circuit, which includes a main contactor, a delta contactor, a star contactor, a thermal relay, and a circuit breaker. A pressure sensor is provided on the air tank. The normally-closed timed closing contact of the second time relay and the first normally-open contact of the third intermediate relay are connected in parallel and then connected in series with the coil of the third intermediate relay to form a first branch. The first normally-closed contact of the third intermediate relay and the coil of the second time relay are connected in series to form a second branch. The first normally-closed contacts of the main contactor, the delta contactor, and the star contactor are connected in series and then respectively connected in series with the first branch and the second branch and then connected to the power supply; the second normally-closed contact of the delta contactor, the normally-closed timed opening contact of the first time relay, and the coil of the star contactor are connected in series to form a third branch, and the two ends of the series circuit of the normally-closed timed opening contact of the first time relay and the coil of the star contactor are connected in parallel with the coil of the first time relay; the normally-closed timed closing contact of the first time relay and the normally-open contact of the delta contactor are connected in parallel and then connected in series with the second normally-closed contact of the star contactor and the coil of the delta contactor in sequence to form a fourth branch; the coil of the main contactor, the third branch, and the fourth branch are connected in parallel to form a fifth branch. The normally-closed contact of the second time relay is connected to one end of the power supply, the other end of the second time relay is connected to one end of a change-over switch. One contact of the change-over switch is connected in series with a stop button and then connected in parallel with a start button and the first normally-open contact of the main contactor to form a sixth branch. The sixth branch is connected in series with the fifth branch and then connected to the other end of the power supply; the other contact of the change-over switch is connected in series with the normally-closed contact of the second intermediate relay and then connected in series with the parallel branch of the first normally-open contact of the first intermediate relay and the second normally-open contact of the main contactor to form a seventh branch. The seventh branch is connected in series with the fifth branch and then connected to the other end of the power supply; the lower limit contact of the pressure sensor is connected in series with the coil of the first intermediate relay and then connected to the power supply, and the upper limit contact of the pressure sensor is connected in series with the coil of the second intermediate relay and then connected to the power supply.

[0005] Advantages of the utility model: A second time relay is added to the circuit to set the operation time of important equipment. During the operation of important equipment, the coil of the second time relay is always energized for timing, and its normally-closed contact disconnects the main control circuit of the air compressor, thereby solving the problem of unstable voltage caused by starting the air compressor during the operation of important equipment and enabling important equipment to operate stably. And this circuit has two control modes: manual and automatic, which can be controlled manually or automatically according to the detection of the pressure sensor. Description of the drawings:

[0006] Figure 1 is the circuit diagram of the utility model.

[0007] Main contactor KM1, delta contactor KM2, star contactor KM3, thermal relay FR, circuit breaker QF, first time relay KT1, second time relay KT2, first intermediate relay KA1, second intermediate relay KA2, second intermediate relay KA2, third intermediate relay KA3, lower limit contact J1, upper limit contact J2, changeover switch SA, stop button SB1, start button SB2, motor M. Detailed implementation mode:

[0008] In the description of the present invention, 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 invention 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, so it cannot be understood as a limitation to the present invention. 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.

[0009] Such as Figure 1As shown in the figure, an air compressor starting control circuit includes a main contactor KM1, a delta contactor KM2, a star contactor KM3, a thermal relay FR, and a circuit breaker QF. A pressure sensor is provided on the air tank. The normally closed contact of the second time relay KT2 is connected in parallel with the first normally open contact of the third intermediate relay KA3 and then connected in series with the coil of the third intermediate relay KA3 to form a first branch. The first normally closed contact of the third intermediate relay KA3 is connected in series with the coil of the second time relay KT2 to form a second branch. The first normally closed contacts of the main contactor KM1, the delta contactor KM2, and the star contactor KM3 are connected in series and then connected in series with the first branch and the second branch respectively and then connected to the power supply; the second normally closed contact of the delta contactor KM2, the normally open contact of the first time relay KT1, and the coil of the star contactor KM3 are connected in series to form a third branch, and the two ends of the series circuit of the normally open contact of the first time relay KT1 and the coil of the star contactor KM3 are connected in parallel with the coil of the first time relay KT1; the normally open contact of the first time relay KT1 is connected in parallel with the normally open contact of the delta contactor KM2 and then connected in series with the second normally closed contact of the star contactor KM3 and the coil of the delta contactor KM2 in sequence to form a fourth branch; the coil of the main contactor KM1, the third branch, and the fourth branch are connected in parallel to form a fifth branch. The normally closed contact of the second time relay KT2 is connected to one end of the power supply, and the other end of the second time relay KT2 is connected to one end of the changeover switch SA. One contact of the changeover switch SA is connected in series with the stop button SB1 and then connected in parallel with the start button SB2 and the first normally open contact of the main contactor KM1 to form a sixth branch. The sixth branch is connected in series with the fifth branch and then connected to the other end of the power supply; the other contact of the changeover switch SA is connected in series with the normally closed contact of the second intermediate relay KA2 and then connected in series with the parallel branch of the normally open contact of the first intermediate relay KA1 and the second normally open contact of the main contactor KM1 to form a seventh branch. The seventh branch is connected in series with the fifth branch and then connected to the other end of the power supply; the lower limit contact J1 of the pressure sensor is connected in series with the coil of the first intermediate relay KA1 and then connected to the power supply, and the upper limit contact J2 of the pressure sensor is connected in series with the coil of the second intermediate relay KA2 and then connected to the power supply.

[0010] The operation time of important equipment can be set through the second time relay KT2, and the operation time of the air compressor can be set through KT1;

[0011] Close the circuit breaker QF1 on the power supply line. When the air compressor is shut down and important equipment is running, the coils of the main contactor KM1, delta contactor KM2, and star contactor KM3 are all de-energized, and their normally closed contacts are closed. The coil of the second time relay KT2 is energized and starts timing, and the normally closed contact of the second time relay is opened. At this time, the circuit between the transfer switch SA and the power supply is disconnected, and the air compressor cannot be started and run. When the important equipment has been shut down for the time set by the second time relay KT2, its normally open timed closed contact is closed - the coil of the third intermediate relay KA3 is energized and self-locked - the normally closed contact of the third intermediate relay KA3 is opened - the coil of the second intermediate relay KT2 is de-energized - the normally closed contact of the second intermediate relay is closed. At this time, the air compressor can be started, and there are two starting methods: manual and automatic. The specific control process is as follows:

[0012] (1) Manual control

[0013] Switch the transfer switch SA to the manual control circuit and press the start button SB2 - the coil of the main contactor KM1 is energized and self-locked, the coil of the star contactor KM3 is energized, and the coil of the first time relay KT1 is energized - the main contacts of the main contactor KM1 and the star contactor KM3 are closed, and the motor M of the air compressor is energized and runs in star; when the running time of the air compressor set by the first time relay KT1 is reached, the coil of the delta contactor KM2 is energized and self-locked - the normally open timed break contact of the first time relay KT1 is opened, and the motor M of the air compressor switches to delta operation. When it is observed that the pressure in the air tank reaches the high pressure, press the stop button SB1 to shut down.

[0014] (2) Automatic control

[0015] Switch the transfer switch SA to the automatic control circuit. When the pressure in the air tank reaches the lower limit of the pressure sensor, the lower limit contact J1 is closed - the coil of the first intermediate relay KA1 is energized - the normally open contact of the first intermediate relay KA1 is closed - the coil of the main contactor KM1 is energized and self-locked, the coil of the first time relay is energized, and the coil of the star contactor KM3 is energized. The motor M is energized and runs in star. When the time set by the first time relay KT1 is reached, the motor M switches to delta operation; when the pressure in the air tank reaches the upper limit of the pressure sensor, the upper limit contact J2 is closed - the coil of the second intermediate relay KA2 is energized - the normally closed contact of the second intermediate relay KA2 is opened - the motor M is shut down.

[0016] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An air compressor starting control circuit, comprising a main contactor (KM1), an angle contactor (KM2), a Y-type contactor (KM3), a thermal relay (FR), and a circuit breaker (QF), characterized in that: A pressure sensor is arranged on the gas cylinder. The power-on delayed closing contact of the second time relay (KT2) is connected in parallel with the first normally open contact of the third intermediate relay (KA3) and then connected in series with the coil of the third intermediate relay (KA3) to form a first branch. The first normally closed contact of the third intermediate relay (KA3) and the coil of the second time relay (KT2) are connected in series to form a second branch. The first normally closed contact of the main contactor (KM1), the first normally closed contact of the angle contactor (KM2) and the first normally closed contact of the Y-type contactor (KM3) are connected in series and then connected to the first branch and the second branch respectively. The branches are connected in series and then connected to a power source; the second normally closed contact of the angular contactor (KM2), the power-on delayed disconnection contact of the first time relay (KT1), and the coil of the Y-type contactor (KM3) are connected in series to form a third branch, and the coil of the first time relay (KT1) and the power-on delayed disconnection contact of the first time relay (KT1) and the Y-type contactor (KM3) are connected in parallel at both ends of the series circuit; the power-on delayed closing contact of the first time relay (KT1) is connected in parallel with the normally open contact of the angular contactor (KM2), and then in sequence with the second contact of the Y-type contactor (KM3). The normally closed contact and the coil of the angular contactor (KM2) are connected in series to form a fourth branch; the coil of the main contactor (KM1), the third branch, and the fourth branch are connected in parallel to form a fifth branch; the normally closed contact of the second time relay (KT2) is connected to one end of the power supply, the other end of the second time relay (KT2) is connected to one end of the conversion switch (SA), a contact of the conversion switch (SA) is connected in series with the stop button (SB1) and then connected in parallel with the start button (SB2) and the first normally open contact of the main contactor (KM1) to form a sixth branch; the sixth branch is connected in series with the fifth branch and then connected to the The other end of the power supply is connected; the other contact of the conversion switch (SA) is connected in series with the normally closed contact of the second intermediate relay (KA2), and then connected in series with the normally open contact of the first intermediate relay (KA1) and the parallel branch of the second normally open contact of the main contactor (KM1) to form a seventh branch, and the seventh branch is connected in series with the fifth branch and then connected to the other end of the power supply; the lower limit contact (J1) of the pressure sensor is connected in series with the coil of the first intermediate relay (KA1) and then connected to the power supply, and the upper limit contact (J2) of the pressure sensor is connected in series with the coil of the second intermediate relay (KA2) and then connected to the power supply.

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