Control loop of external motor cooling device

Abstract

The utility model discloses a control loop of an external motor cooling device, which relates to the technical field of cooling device control, and is characterized in that a main motor, a current transformer and a current relay are arranged, so that a power line of the main motor is connected with the current transformer, and the current transformer is in mutual inductance connection with the current relay; the current relay is connected in series with the cooling device, and when the current passing through the current relay reaches a set value, the auxiliary contact of the current relay is automatically closed, and the cooling device is automatically started at the same time, so that heat dissipation and temperature reduction are carried out on the main motor; the cooling device can achieve the automatic start-stop function according to the change of the load, it is ensured that the cooling device can be rapidly and effectively put into use under the large-load condition, an operator does not need to conduct on-site operation, and therefore great convenience is brought to the operator.

Description

Technical Field

[0001] This utility model relates to the field of cooling device control technology, and in particular to a control circuit for an external motor cooling device. Background Technology

[0002] Thermal power plants use a large number of 6kV, 380V, or other voltage-level AC motors. During normal operation, the motors themselves have built-in fans that dissipate the heat generated, ensuring the windings and bearings maintain normal operating temperatures. However, as the motors age or the ambient temperature becomes too high, the motor's own cooling system may become insufficient to keep the winding temperatures within the normal range, accelerating motor aging and increasing the risk of damage. Therefore, temporary axial flow fans are added on-site as cooling devices to improve motor cooling efficiency.

[0003] Temporarily added cooling devices are usually started and stopped manually by switching the power switch on and off locally. The degree of automation is not high. When the motor stops or the current is low, the axial fan can be stopped, but the operator needs to go to the site to operate it, which increases the inconvenience of operation. Utility Model Content

[0004] This invention aims to overcome the problem that temporary cooling devices rely on manual on / off power switches, resulting in low automation. Furthermore, while the axial fan can be stopped when the motor is off or under low current load, operators still need to be physically present, increasing operational inconvenience. The technical problem this invention addresses is providing a control circuit for an external motor cooling device that allows for on-site start / stop operation of the cooling device without requiring local intervention, greatly enhancing operational convenience.

[0005] To solve the above-mentioned technical problems, this utility model provides a control circuit for an external motor cooling device, including a main motor, a current transformer and a current relay. The power line of the main motor is connected to the current transformer, the current transformer and the current relay are inductively connected, and the cooling device is connected in series with the current relay.

[0006] Preferably, the current relay is connected in parallel with a receiver, and the receiver is connected in parallel with a manual start / stop button.

[0007] Preferably, the current relay, the receiver, and the manual start / stop button form a parallel circuit.

[0008] Preferably, the parallel circuit is connected in series with a starting contactor coil.

[0009] Preferably, the parallel circuit is connected in series with a control circuit power switch, and the control circuit power switch is connected in series with a main power switch.

[0010] Specifically, the main power switch is 380V AC.

[0011] Preferably, a control power fuse is connected in series between the control circuit power switch and the main power switch.

[0012] Specifically, the control power supply fuse is used to blow overcurrent when a short circuit fault occurs in the control circuit, thereby providing safety protection for the equipment.

[0013] Preferably, the main power switch is connected in series with a cooling device, and a motor power fuse and a starting contactor main contact are connected in series between the cooling device and the main power switch.

[0014] Specifically, the motor power fuse is used to blow overcurrent when a short circuit fault occurs in the cooling device, thus providing safety protection for the equipment.

[0015] Preferably, the receiver is wirelessly connected to a transmitter, and the transmission distance between the receiver and the transmitter is 100 meters to 500 meters.

[0016] Preferably, the receiver is a wireless I / O transmission receiver, and the transmitter is a wireless I / O transmission transmitter.

[0017] Preferably, the power supply of the wireless I / O transmission receiver is 220V AC, the receiving frequency of the wireless I / O transmission receiver is 420MHz~450MHz, the output mode of the wireless I / O transmission receiver is a jog mode with two pairs of normally open contacts, the output contact capacity of the wireless I / O transmission receiver is 10A, the power supply of the wireless I / O transmission transmitter is 12V DC, the transmission frequency of the wireless I / O transmission transmitter is 420MHz~450MHz, and the input mode of the wireless I / O transmission transmitter is a dry contact mode.

[0018] Specifically, the wireless I / O transmission receiver can be installed locally using a DIN rail mounting method.

[0019] Beneficial effects

[0020] This invention incorporates a main motor, a current transformer, and a current relay. The main motor's power line is connected to the current transformer, which inducts with the current relay. The current relay is connected in series with a cooling device. Furthermore, when the current through the current relay reaches a set value, the relay's auxiliary contacts automatically engage, simultaneously activating the cooling device to dissipate heat from the main motor. This allows the cooling device to automatically start and stop based on load changes, ensuring rapid and effective operation under heavy loads without requiring on-site operator intervention, thus providing significant convenience to operators.

[0021] Meanwhile, this utility model sets up a wireless I / O transmitter and a wireless I / O receiver, and ensures that the transmission frequency of the wireless I / O transmitter and the reception frequency of the wireless I / O receiver are matched. When the operator presses the start button of the wireless I / O transmitter from a distance, the local wireless I / O receiver will generate a response. The output contact of the local wireless I / O receiver can be remotely closed to form a loop, thereby realizing the remote start and stop of the cooling device without the need for on-site operation, thus bringing great convenience to the operator.

[0022] This invention enables remote start / stop of the cooling device by setting a manual start / stop button and ensuring that the manual start / stop button is connected in series with the cooling device. This allows the cooling device to be started and stopped remotely without the need for on-site operation by an operator, while still retaining the function of on-site operation via the manual start / stop button. As a temporary alternative emergency solution, this invention makes the function of the control circuit more complete. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the control circuit connection of the external motor cooling device in this utility model.

[0025] The following are the labels in the attached diagram: 1. Main power switch; 2. Motor power fuse; 3. Starting contactor coil; 31. Starting contactor main contact; 4. Cooling device; 5. Control power fuse; 6. Control circuit power switch; 7. Manual start / stop button; 8. Receiver; 9. Transmitter; 10. Current relay; 11. Current transformer; 12. Main motor. Detailed Implementation

[0026] To further understand the present invention, the following detailed description is provided in conjunction with the accompanying drawings and specific embodiments. It should be understood that the embodiments are merely illustrative and not intended to limit the scope of the invention.

[0027] Example 1

[0028] A control circuit for an external motor cooling device, such as Figure 1 As shown, it includes a main motor 12, a current transformer 11 and a current relay 10. The power line of the main motor 12 is connected to the current transformer 11. The current transformer 11 is inductively connected to the current relay 10. The current relay 10 is connected in series with a cooling device 4.

[0029] The current relay 10 is connected in parallel with a receiver 8, and the receiver 8 is connected in parallel with a manual start / stop button 7.

[0030] The current relay 10, the receiver 8, and the manual start / stop button 7 form a parallel circuit.

[0031] The parallel circuit is connected in series with a starting contactor coil 3.

[0032] The parallel circuit is connected in series with a control circuit power switch 6, and the control circuit power switch 6 is connected in series with a main power switch 1.

[0033] Specifically, the main power switch 1 is a 380V AC power supply.

[0034] A control power fuse 5 is connected in series between the control circuit power switch 6 and the main power switch 1.

[0035] Specifically, the control power supply fuse 5 is used to blow overcurrent when a short circuit fault occurs in the control circuit, thereby providing safety protection for the equipment.

[0036] The main power switch 1 is connected in series with a cooling device 4, and a motor power fuse 2 and a starting contactor main contact 31 are connected in series between the cooling device 4 and the main power switch 1.

[0037] Specifically, the motor power fuse 2 is used to blow overcurrent when the cooling device 4 experiences a short circuit fault, thus providing safety protection for the equipment.

[0038] The receiver 8 is wirelessly connected to the transmitter 9, and the transmission distance between the receiver 8 and the transmitter 9 is 100 meters to 500 meters.

[0039] The receiver 8 is a wireless I / O transmission receiver, and the transmitter 9 is a wireless I / O transmission transmitter.

[0040] The wireless I / O transmission receiver is powered by 220V AC, and its receiving frequency is 420MHz to 450MHz. Its output mode is a jog mode with two pairs of normally open contacts, and its output contact capacity is 10A. The wireless I / O transmission transmitter is powered by 12V DC, and its transmission frequency is 420MHz to 450MHz. Its input mode is a dry contact mode.

[0041] Specifically, the wireless I / O transmission receiver can be installed locally using a DIN rail mounting method.

[0042] Working principle: For the entire control circuit, when the main power switch 1 is closed, the cooling device 4 in the circuit enters a hot standby state. The control circuit power switch 6 in the control circuit is then closed, ensuring that the entire control circuit is connected to the main power switch 1 and is energized. Therefore, the working process of the entire control circuit can be specifically divided into the following three states:

[0043] In the first scenario, a set of current transformers 11 are connected to the primary circuit of the main motor 12, meaning the power supply line of the main motor 12 is connected to the current transformers 11. A current relay 10 is connected to the secondary circuit, meaning the current transformers 11 and the current relay 10 are inductively connected. A threshold value is set for the current passing through the current relay 10. When the current passing through the current relay 10 reaches the set threshold value, the auxiliary contacts of the current relay 10 will close, and the main contacts 31 of the starting contactor will close. At this time, the current relay 10, the starting contactor coil 3, the control power fuse 5, and the motor power fuse 2 are all activated. The main contact 31 of the start contactor, the cooling device 4, the main power switch 1 and the control circuit power switch 6 form the first closed circuit. The cooling device 4 starts and begins to dissipate heat and cool the main motor 12. This allows the cooling device 4 to automatically start and stop according to the load changes, ensuring that the cooling device can be quickly and effectively put into operation under heavy load without the need for on-site operation by the operator. When the current value through the current relay 10 is less than the set threshold value, the auxiliary contact of the current relay 10 will open, causing the first closed circuit to break and the cooling device 4 to stop working, thus bringing great convenience to the operator.

[0044] In the second scenario, receiver 8 is installed in the control loop. Receiver 8 is a wireless I / O transmitter with a receiving frequency of 420MHz to 450MHz. Its output mode is a jog mode with two pairs of normally open contacts. The output contact capacity is 220VAC / 110VDC 10A, and the power supply is 220V AC, which can be taken from the control loop's AC power supply. It can be installed locally using a DIN rail mounting method. Simultaneously, a transmitter 9, a handheld wireless I / O transmitter, is installed at a remote location to match receiver 8. The transmitter's transmission frequency is 420MHz to 450MHz, matching the receiving frequency of the wireless I / O transmitter. It is powered by 12V DC, and the input mode is dry contact. The wireless transmission distance between receiver 8 and transmitter 9 is 100 meters to 500 meters. When the cooling device 4 needs to be activated, a button is used to connect to the input DI contact of the wireless I / O transmitter. When the operator... After pressing the button remotely, the transmitter 9 inputs a DI switch signal, and the local receiver 8 outputs a DO contact to remotely close the circuit. At this time, the receiver 9, the start contactor coil 3, the control power fuse 5, the motor power fuse 2, the start contactor main contact 31, the cooling device 4, the main power switch 1, and the control circuit power switch 6 form a second closed circuit. The cooling device 4 starts to dissipate heat and cool the main motor 12, realizing remote start and stop of the cooling device without the need for on-site operation. When it is necessary to disconnect the second closed circuit and stop the operation of the cooling device 4, the operation of the cooling device 4 can be stopped by performing the corresponding operation on the wireless I / O transmitter remotely.

[0045] In the third scenario, a manual start / stop button 7 is installed in the control circuit. When the operator closes the manual start / stop button 7 locally, the manual start / stop button 7, the start contactor coil 3, the control power fuse 5, the motor power fuse 2, the start contactor main contact 31, the cooling device 4, the main power switch 1, and the control circuit power switch 6 form a third closed loop. The cooling device 4 is activated to dissipate heat and cool the main motor 12. This allows the entire control circuit to retain the function of local operation via the manual start / stop button while achieving remote control and automatic start. As a temporary alternative emergency solution, this makes the function of the control circuit more complete.

[0046] Furthermore, the motor power supply fuse and the control power supply fuse are used to blow overcurrent circuits when a short circuit occurs in the cooling device 4 or the control circuit, so as to protect the safety of the equipment.

[0047] Furthermore, the DI input of the wireless I / O transmitter can be replaced by other dry contact methods, such as the DO output of a remote DCS control card.

[0048] Furthermore, the cooling device 4 in this control loop can also be a 220V or other voltage level device.

[0049] Furthermore, this control loop can be integrated into a control cabinet, facilitating on-site maintenance and management.

[0050] The above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although the utility model has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of this utility model. Any modifications or equivalent substitutions that do not depart from the spirit and scope of this utility model should be covered within the protection scope of the claims of this utility model.

Claims

1. A control circuit for an external motor cooling device, characterized in that, Including main motor (12), current transformer (11) and current relay (10), the power line of main motor (12) is connected with current transformer (11), current transformer (11) is connected with current relay (10), current relay (10) is connected with cooling device (4).

2. A control circuit for an external motor cooling device as defined in claim 1, wherein, The current relay (10) is connected with the receiver (8), and the receiver (8) is connected with the manual start-stop button (7).

3. A control circuit for an external motor cooling device as defined in claim 2, wherein The current relay (10), the receiver (8) and the manual start-stop button (7) constitute a parallel circuit.

4. A control circuit for an external motor cooling device as defined in claim 3, wherein The parallel circuit is connected with a start contactor coil (3).

5. A control circuit for an external motor cooling device as defined in claim 3, wherein, The parallel circuit is connected with a control circuit power switch (6), and the control circuit power switch (6) is connected with a power switch (1).

6. A control circuit for an external motor cooling device as defined in claim 5, wherein The control circuit power switch (6) and the power switch (1) are connected with a control power fuse (5).

7. A control circuit for an external motor cooling device as defined in claim 5, wherein The power switch (1) is connected with a cooling device (4), and the cooling device (4) is connected with the power switch (1) between the motor power fuse (2) and the start contactor main contact (31).

8. A control circuit for an external motor cooling device as defined in claim 2, wherein, The receiver (8) is wirelessly connected with a transmitter (9), and the transmission distance between the receiver (8) and the transmitter (9) is 100-500 meters.

9. A control circuit for an external motor cooling device as defined in claim 8, wherein, The receiver (8) is a wireless I / O transmission receiver, and the transmitter (9) is a wireless I / O transmission transmitter.

10. A control circuit for an external motor cooling device as defined in claim 9, wherein, The power supply of the wireless I / O transmission receiver is 220V AC, the receiving frequency of the wireless I / O transmission receiver is 420-450MHz, the output mode of the wireless I / O transmission receiver is the jog mode of two pairs of normally open contact points, the output contact capacity of the wireless I / O transmission receiver is 10A, the power supply of the wireless I / O transmission transmitter is 12V DC, the transmission frequency of the wireless I / O transmission transmitter is 420-450MHz, and the input mode of the wireless I / O transmission transmitter is a dry contact mode.

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