Control circuit for monitoring safe operation of double-speed motor

Abstract

The utility model discloses a control circuit used for monitoring safe operation of a double-speed motor. The control circuit comprises a control loop and a monitoring loop. Wherein the control loop comprises a normally closed contact of a first relay KA, a normally closed contact of a first thermal relay FR1, a normally closed contact of a second thermal relay FR2, a normally closed contact of a stop button SB3, a first control circuit, a normally open contact of a first contactor KM1, a second control circuit, a normally open contact of a second contactor KM2 and a coil of a third contactor KM3; the monitoring loop comprises a first indicating lamp HL1, a normally-closed contact of a first contactor KM1, a second indicating lamp HL2, a normally-closed contact of a second contactor KM2, a third indicating lamp HL3, a normally-closed contact of a third contactor KM3, a fourth indicating lamp HL4, a normally-closed contact of a first start button SB1, a normally-closed contact of a second start button SB2 and a normally-closed contact of a stop button SB3.

Description

Technical Field:

[0001] The utility model relates to the technical field of monitoring the operation of a two-speed motor, and particularly relates to a control circuit for monitoring the safe operation of a two-speed motor. Background Art:

[0002] In a production workshop, when all equipment is working, the fan needs to increase power for heat dissipation, and when some equipment is working, the power needs to be reduced on this basis. To achieve the above purpose, the ventilation equipment uses a two-speed motor to reduce energy consumption and achieve the effect of energy conservation and emission reduction. That is, after the motor starts, when it is necessary to change the motor speed according to the actual situation on site, we can change the circuit connection method of the motor through different buttons, from Δ type to Y type, or from Y type to Δ type, so as to freely change the motor speed. During the operation of the two-speed motor, the motor often burns out or fails to start. However, since it is time-consuming and laborious for operators to troubleshoot circuit faults, it seriously affects the ventilation effect of the workshop. Content of the Utility Model:

[0003] The purpose of the utility model is to provide a control circuit for monitoring the safe operation of a two-speed motor.

[0004] The purpose of the utility model is implemented by the following technical solution: A control circuit for monitoring the safe operation of a two-speed motor, which includes a control loop and a monitoring loop;

[0005] The control loop includes the normally closed contact of the first relay KA, the normally closed contact of the stop button SB3, the first control line, the normally open contact of the first contactor KM1, the second control line, the normally open contact of the second contactor KM2, and the coil of the third contactor KM3;

[0006] The normally open contact of the first start button SB1, the normally closed contact of the second start button SB2, the normally closed contact of the second contactor KM2, the normally closed contact of the third contactor KM3, and the coil of the first contactor KM1 are connected in series to form the first control line, and the normally open contact of the first contactor KM1 is connected in parallel at both ends of the normally open contact of the first start button SB1;

[0007] The normally open contact of the second start button SB2, the normally closed contact of the first start button SB1, the normally closed contact of the first contactor KM1, and the coil of the second contactor KM2 are connected in series to form the second control line. The normally open contact of the second contactor KM2 is connected in parallel at both ends of the normally open contact of the second start button SB2, and the coil of the third contactor KM3 is connected in parallel at both ends of the coil of the second contactor KM2; After the first control line and the second control line are connected in parallel, they are connected in series with the normally closed contact of the first relay KA and the normally closed contact of the stop button SB3 to form a closed loop;

[0008] The normally closed contact of the first contactor KM1 is connected in series with the second indicator light HL2 to form a first branch; the normally closed contact of the second contactor KM2 is connected in series with the third indicator light HL3 to form a second branch; the normally closed contact of the third contactor KM3 is connected in series with the fourth indicator light HL4 to form a third branch; after the first indicator light HL1, the first branch, the second branch, and the third branch are connected in parallel, they are connected in series with the normally closed contacts of the first start button SB1, the second start button SB2, and the stop button SB3 to form the monitoring circuit;

[0009] After the control circuit and the monitoring circuit are connected in parallel, they are connected in series with the control switch QF2 on the three-phase power line.

[0010] Preferably, it further includes a motor cooling circuit. The coil of the first relay KA and the normally closed contact of the time relay KT that is delayed to open are connected in series to form a fourth branch. After the fourth branch is connected in parallel with the coil of the time relay KT, it is connected in series with the normally open contact of the stop button SB3 between the live wire L and the neutral wire N. A normally open contact of the first relay KA is connected in parallel at both ends of the normally open contact of the stop button SB3, and a motor cooling indicator light HL5 is connected in parallel at both ends of the coil of the first relay KA to form the motor cooling circuit; after the motor cooling circuit, the control circuit, and the monitoring circuit are connected in parallel, they are connected in series with the control switch QF2 on the three-phase power line.

[0011] Preferably, the normally closed contacts of the first thermal relay FR1 and the second thermal relay FR2 are connected in series between the normally closed contact of the first relay KA in the control circuit and the normally closed contact of the stop button SB3.

[0012] Advantages of the present invention: The present invention is provided with a control circuit, a monitoring circuit, and a motor cooling circuit. The start and stop of the double-speed motor are controlled through the control circuit, and the motor can be switched between low-speed operation and high-speed operation; through the monitoring circuit, on the one hand, it monitors whether there are problems with the series circuit of the first start button SB1, the second start button SB2, and the stop button SB3 or whether the components in this circuit are damaged. On the other hand, it simultaneously monitors whether there are problems with the low-speed operation circuit and the high-speed operation circuit or whether the components in the corresponding circuits are damaged, prompting relevant maintenance personnel to perform maintenance in a timely manner; through the motor cooling circuit, the cooling time of the double-speed motor is guaranteed, and the double-speed motor is prevented from being started during the cooling process. Description of the drawings:

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0014] Figure 1 is a circuit schematic diagram of the present utility model.

[0015] Figure 2 is a circuit schematic diagram of the main circuit controlled by the present utility model.

[0016] The markings of each component in the attached drawings are as follows: control circuit 1, first control line 1.1, second control line 1.2, monitoring circuit 2, motor cooling circuit 3, control switch QF2, first relay KA, first thermal relay FR1, second thermal relay FR2, stop button SB3, first start button SB1, first contactor KM1, second contactor KM2, third contactor KM3, second start button SB2, first indicator light HL1, first branch 2.1, second indicator light HL2, second branch 2.2, third indicator light HL3, third branch 2.3, fourth indicator light HL4, fourth branch 3.1, time relay KT, motor cooling indicator light HL5, main switch QF1, two-speed motor M3. Specific implementation manner:

[0017] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present utility model.

[0018] As Figure 1 - Figure 2 shown, a control circuit for monitoring the safe operation of a two-speed motor includes a control circuit 1, a monitoring circuit 2, and a motor cooling circuit 3; after the control circuit 1, the monitoring circuit 2, and the motor cooling circuit 3 are connected in parallel, they are connected in series with the control switch QF2 on the three-phase power line;

[0019] The control circuit 1 is used to control the start and stop of the two-speed motor M3 and can switch between low-speed operation and high-speed operation; the monitoring circuit 2 is used to monitor whether the lines of the first start button SB1, the second start button SB2, and the stop button SB3 are connected on the one hand, and to monitor whether the low-speed operation circuit and the high-speed operation circuit of the two-speed motor M3 are connected on the other hand; the motor cooling circuit 3 is used to ensure the cooling time of the two-speed motor M3 and prevent operators from starting the two-speed motor M3 during the cooling process;

[0020] The control loop 1 includes the normally closed contact of the first relay KA, the normally closed contact of the first thermal relay FR1, the normally closed contact of the second thermal relay FR2, the normally closed contact of the stop button SB3, the first control line 1.1, the normally open contact of the first contactor KM1, the second control line 1.2, the normally open contact of the second contactor KM2, and the coil of the third contactor KM3;

[0021] The normally open contact of the first start button SB1, the normally closed contact of the second start button SB2, the normally closed contact of the second contactor KM2, the normally closed contact of the third contactor KM3, and the coil of the first contactor KM1 are connected in series to form the first control line 1.1. The normally open contact of the first contactor KM1 is connected in parallel at both ends of the normally open contact of the first start button SB1;

[0022] The normally open contact of the second start button SB2, the normally closed contact of the first start button SB1, the normally closed contact of the first contactor KM1, and the coil of the second contactor KM2 are connected in series to form the second control line 1.2. The normally open contact of the second contactor KM2 is connected in parallel at both ends of the normally open contact of the second start button SB2. The coil of the third contactor KM3 is connected in parallel at both ends of the coil of the second contactor KM2;

[0023] After the first control line 1.1 and the second control line 1.2 are connected in parallel, they are connected in series with the normally closed contact of the first relay KA, the normally closed contact of the first thermal relay FR1, the normally closed contact of the second thermal relay FR2, and the normally closed contact of the stop button SB3 to form a closed loop;

[0024] The monitoring loop 2 includes the normally closed contact of the first start button SB1, the normally closed contact of the second start button SB2, the normally closed contact of the stop button SB3, the first indicator light HL1, the first branch 2.1, the second branch 2.2, and the third branch 2.3;

[0025] The normally closed contact of the first contactor KM1 is connected in series with the second indicator light HL2 to form a first branch 2.1. The normally closed contact of the second contactor KM2 is connected in series with the third indicator light HL3 to form a second branch 2.2. The normally closed contact of the third contactor KM3 is connected in series with the fourth indicator light HL4 to form a third branch 2.3. After the first indicator light HL1, the first branch 2.1, the second branch 2.2, and the third branch 2.3 are connected in parallel, they are connected in series with the normally closed contacts of the first start button SB1, the second start button SB2, and the stop button SB3 to form a monitoring circuit 2. Among them, the on and off of the first indicator light HL1 indicates that there may be a problem with the series circuit of the first start button SB1, the second start button SB2, and the stop button SB3 or the components in this circuit are damaged, prompting relevant maintenance personnel to maintain in time. When the first indicator light HL1 is on, the on and off of the second indicator light HL2 indicates that there may be a problem with the low-speed operation circuit of the two-speed motor M3 or the components in this circuit are damaged, prompting relevant maintenance personnel to maintain in time. When the first indicator light HL1 is on, the on and off of the third indicator light HL3 and the fourth indicator light HL4 indicate that there may be a problem with the high-speed operation circuit of the two-speed motor M3 or the components in this circuit are damaged, prompting relevant maintenance personnel to maintain in time.

[0026] The motor cooling circuit 3 includes a fourth branch 3.1, a time relay KT coil, a normally open contact of the stop button SB3, a normally open contact of the first relay KA, and a motor cooling indicator light HL5.

[0027] The first relay KA coil and the normally closed contact of the time relay KT with delayed disconnection are connected in series to form a fourth branch 3.1. After the fourth branch 3.1 is connected in parallel with the time relay KT coil, it is connected in series with the normally open contact of the stop button SB3 between the live wire L and the neutral wire N. A normally open contact of the first relay KA is connected in parallel at both ends of the normally open contact of the stop button SB3. A motor cooling indicator light HL5 is connected in parallel at both ends of the first relay KA coil to form the motor cooling circuit 3. Among them, the lighting of the motor cooling indicator light HL5 indicates that the two-speed motor M3 is in the cooling time and the two-speed motor M3 is not allowed to be started.

[0028] The main circuit controlled by the present utility model is of an existing structure, which includes a main switch QF1, normally open contacts of a first contactor KM1, normally open contacts of a second contactor KM2, normally open contacts of a third contactor KM3, a first thermal relay FR1 coil, a second thermal relay FR2 coil, and a two-speed motor M3; one end of the main switch QF1 is connected to a power supply, and the other end of the main switch QF1 is respectively connected to the normally open contacts of the first contactor KM1 and the normally open contacts of the second contactor KM2. Among them, the other end of the normally open contact of the first contactor KM1 is connected to the two-speed motor M3 through the first thermal relay FR1 coil, and the other end of the normally open contact of the second contactor KM2 is connected to the normally open contact of the third contactor KM3 and the second thermal relay FR2 coil. The other end of the second thermal relay FR2 coil is connected to the two-speed motor M3, constituting the main circuit controlled by the present utility model; in the main circuit, after the current passes through the main switch QF1, it is divided into two lines. One line enters the two-speed motor M3 after passing through the normally open contact of the first contactor KM1, forming a low-speed operation circuit, and the other line enters the two-speed motor M3 after passing through the normally open contacts of the second contactor KM2 and the third contactor KM3, forming a high-speed operation circuit. Between the low-speed operation circuit and the high-speed operation circuit, by starting and switching the control circuit 1, the two-speed motor M3 is put into different states to achieve the purpose of speed change.

[0029] Working process: After closing the main switch QF1 and the control switch QF2, when the first indicator light HL1 is on, it indicates that the first start button SB1, the second start button SB2, and the stop button SB3 are in good condition. When the second indicator light HL2 is on, it indicates that the normally closed contact of the first contactor KM1 is in good condition. When the third indicator light HL3 is on, it indicates that the normally closed contact of the second contactor KM2 is in good condition. When the fourth indicator light HL4 is on, it indicates that the normally closed contact of the third contactor KM3 is in good condition. When one of the indicator lights is not on, the fault can be accurately judged;

[0030] After the first indicator light HL1, the second indicator light HL2, the third indicator light HL3, and the fourth indicator light HL4 are all on, it indicates that the series circuit of the first start button SB1, the second start button SB2, and the stop button SB3 is in good condition, and both the low-speed operation circuit and the high-speed operation circuit of the two-speed motor M3 are in good condition, allowing the first start button SB1 or the second start button SB2 in the control circuit 1 to be pressed;

[0031] When it is necessary to start the two-speed motor M3 in low-speed operation, press the first start button SB1. The first contactor KM1 coil is energized and attracted to drive the normally open contact of the first contactor KM1 to close, forming self-locking. The normally open contact of the first contactor KM1 in the main circuit closes, and the two-speed motor M3 operates at low speed; and when the first start button SB1 is pressed, the second control line 1.2 is cut off to prevent the second control line 1.2 from being connected;

[0032] When it is necessary to start the double-speed motor M3 to run at high speed, press the second start button SB2 to cut off the first control circuit 1.1, so that the coil of the first contactor KM1 loses power, and the double-speed motor M3 stops running at low speed; at the same time, the coil of the second contactor KM2 is energized and attracted to drive the normally open contact of the second contactor KM2 to close, forming self-locking, and the coil of the third contactor KM3 is energized. The normally open contacts of the second contactor KM2 and the third contactor KM3 in the main circuit are closed at the same time, and the double-speed motor M3 runs at high speed;

[0033] When it is necessary to stop the double-speed motor M3 from running, press the stop button SB3 to cut off the control circuit 1, and the double-speed motor M3 stops running; at the same time, the coil of the first relay KA in the motor cooling circuit 3 is energized and attracted to drive the normally open contact of the first relay KA to close, forming self-locking, and the normally closed contact of the first relay KA is disconnected to cut off the control circuit 1 to prevent the double-speed motor M3 from starting; in addition, the motor cooling indicator HL5 is on, indicating that the double-speed motor M3 is in the cooling process and it is not allowed to start the double-speed motor M3. At the same time, the coil of the time relay KT is energized and starts timing;

[0034] When the coil of the time relay KT reaches the set time, the normally closed delay-disconnecting contact of the time relay KT is disconnected to cut off the fourth branch 3.1, the coil of the first relay KA loses power, and the normally closed contact of the first relay KA in the control circuit 1 is closed. At the same time, the motor cooling indicator HL5 goes out, allowing the double-speed motor M3 to be started again.

[0035] The above is only the preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A control circuit for monitoring the safe operation of a dual-speed motor, characterized in that: It includes a control loop and a monitoring loop; The control circuit includes a normally closed contact of the first relay KA, a normally closed contact of the stop button SB3, a first control circuit, a normally open contact of the first contactor KM1, a second control circuit, a normally open contact of the second contactor KM2, and a coil of the third contactor KM3; The normally open contact of the first start button SB1, the normally closed contact of the second start button SB2, the normally closed contact of the second contactor KM2, the normally closed contact of the third contactor KM3, and the coil of the first contactor KM1 are connected in series to form a first control circuit, and the normally open contacts of the first contactor KM1 are connected in parallel at both ends of the normally open contact of the first start button SB1; The normally open contact of the second start button SB2, the normally closed contact of the first start button SB1, the normally closed contact of the first contactor KM1, and the coil of the second contactor KM2 are connected in series to form a second control circuit, the normally open contacts of the second contactor KM2 are connected in parallel at both ends of the normally open contact of the second start button SB2, and the coil of the third contactor KM3 is connected in parallel at both ends of the coil of the second contactor KM2; after the first control circuit is connected in parallel with the second control circuit, it is connected in series with the normally closed contact of the first relay KA and the normally closed contact of the stop button SB3 to form a closed loop; The normally closed contact of the first contactor KM1 is connected in series with the second indicator light HL2 to form a first branch, the normally closed contact of the second contactor KM2 is connected in series with the third indicator light HL3 to form a second branch, and the normally closed contact of the third contactor KM3 is connected in series with the fourth indicator light HL4 to form a third branch; the first indicator light HL1, the first branch, the second branch, and the third branch are connected in parallel and then connected in series with the normally closed contact of the first start button SB1, the normally closed contact of the second start button SB2, and the normally closed contact of the stop button SB3 to form the monitoring circuit; After the control circuit and the monitoring circuit are connected in parallel, they are connected in series with the control switch QF2 on the three-phase power line.

2. A control circuit for monitoring the safe operation of a dual-speed motor according to claim 1, characterized in that: It also includes a motor cooling circuit, in which the delayed-off normally closed contacts of the first relay KA coil and the time relay KT are connected in series to form a fourth branch. After the fourth branch is connected in parallel with the time relay KT coil, it is connected in series with the normally open contacts of the stop button SB3 between the live wire L and the neutral wire N. The normally open contacts of the first relay KA are connected in parallel at both ends of the normally open contacts of the stop button SB3, and the motor cooling indicator lights HL5 are connected in parallel at both ends of the first relay KA coil, forming the motor cooling circuit; after the motor cooling circuit, the control circuit and the monitoring circuit are connected in parallel, they are connected in series with the control switch QF2 on the three-phase power line.

3. A control circuit for monitoring the safe operation of a dual-speed motor according to claim 1 or 2, characterized in that: The normally closed contact of the first thermal relay FR1 and the normally closed contact of the second thermal relay FR2 are connected in series between the normally closed contact of the first relay KA of the control loop and the normally closed contact of the stop button SB3.

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