Automatic cooling device for high voltage motor bearings

Abstract

This invention discloses an automatic cooling device for high-voltage motor bearings, belonging to the field of high-voltage motor equipment technology. The device includes a temperature acquisition unit, a control unit, a cooling execution unit, and a power supply protection unit. The temperature acquisition unit reuses the spare core of the original temperature sensing element of the high-voltage motor bearing to acquire the bearing temperature signal in real time. The control unit automatically controls the start and stop of the cooling fan according to a preset temperature threshold using a secondary temperature controller. The cooling execution unit uses a fixedly installed cooling fan to precisely target and cool the bearing housing. This invention achieves fully automatic closed-loop cooling control of the bearing temperature without manual intervention, without damaging the original structure of the motor. It has low modification costs, strong versatility, and stable and reliable cooling effect. It can effectively protect the bearing lubricating oil film, avoid motor tripping accidents caused by bearing overheating, and significantly improve the safety and stability of high-voltage motor operation. It is suitable for high-voltage motor equipment in various industrial scenarios.

Description

Technical Field

[0001] This invention relates to the field of high-voltage motor equipment technology, and in particular to an automatic cooling device for high-voltage motor bearings. Background Technology

[0002] High-voltage motors are core power equipment in industries such as power, metallurgy, chemical, and mining. Their safety and stability directly determine the continuous operation capability of the entire production system. As the core rotating support component of high-voltage motors, the operating temperature of bearings is a key indicator of their health. Abnormally high bearing temperatures can directly damage the lubricating oil film inside the bearing, leading to accelerated bearing wear, abnormal noise and vibration. In severe cases, it can cause bearing seizure, high-voltage motor overheating and tripping, resulting in unplanned shutdowns of the entire production unit and causing huge economic losses to the enterprise.

[0003] Currently, the industry's conventional solutions to the problem of excessive bearing temperature rise in high-voltage motors are mainly divided into two categories: one is to rely on the inherent heat dissipation structure of the high-voltage motor itself. However, the bearings of high-voltage motors are all sealed with front and rear oil baffles, which restricts the ventilation path in the bearing area and results in extremely poor natural cooling, making it impossible to cope with the abnormal temperature rise of the bearings; the other is that after the operators discover that the bearing temperature exceeds the standard, they temporarily set up an external axial flow fan on site to force the bearing housing to cool down.

[0004] The aforementioned existing temporary air-cooling technology has many intractable technical defects in practical applications:

[0005] The response is severely delayed, missing the optimal cooling opportunity. The existing solution relies on manual detection of temperature anomalies before taking action. From the DCS system alarm, personnel rushing to the site, setting up the fan, to completing the wiring and starting the cooling process, a long processing time is required. During this period, the bearing temperature will continue to rise, which can easily trigger the motor over-temperature trip protection, making it impossible to achieve a rapid response to abnormal temperature rise.

[0006] Manual operation is cumbersome and poses serious safety hazards. Temporarily setting up fans requires on-site personnel to carry equipment, secure it on-site, and temporarily connect wires. However, the areas where high-voltage motors are located are often high-voltage live-line work areas. Temporary wiring operations pose significant safety risks of electric shock and equipment short circuits, which does not comply with industrial site safety production standards.

[0007] Automatic closed-loop control is not possible, resulting in high energy consumption and poor temperature control. Temporary fans cannot automatically start and stop based on bearing temperature after startup; they either continue running, causing unnecessary energy waste, or are not manually shut down in a timely manner, leading to repeated fluctuations in bearing temperature and an inability to stably control the bearing temperature within a safe operating range.

[0008] The cooling effect is unstable and the targeting is poor. The temporary fan is not fixed in its installation position and cannot be accurately aimed at the core heat dissipation area of ​​the bearing housing. The cooling air path and air volume are unstable, the cooling efficiency is low, it is difficult to quickly suppress the bearing temperature rise, and it cannot effectively protect the bearing lubricating oil film.

[0009] It is not suitable for unattended operation scenarios. For scenarios such as remote pumping stations and unattended substations, it cannot handle abnormal bearing temperature rise in a timely manner, and it completely fails to meet the equipment protection requirements under unattended operating conditions. Summary of the Invention

[0010] In view of the shortcomings of the prior art, the purpose of this invention is to provide an automatic cooling device for high-voltage motor bearings, which realizes real-time online monitoring and automatic closed-loop cooling control of high-voltage motor bearing temperature. It can quickly respond to abnormal bearing temperature rise without manual intervention, without damaging the original structure of the motor, and the cooling effect is stable and reliable. At the same time, it eliminates the safety risks of temporary on-site operations, effectively avoids motor tripping accidents caused by bearing overheating, and greatly improves the safety and stability of high-voltage motor operation.

[0011] An automatic cooling device for high-voltage motor bearings includes a temperature acquisition unit, a control unit, a cooling execution unit, and a power supply protection unit.

[0012] The temperature acquisition unit includes a temperature sensing element integrated with the high-voltage motor bearing. The temperature sensing element is equipped with a spare conductor, which is connected to the signal input terminal of the control unit for real-time acquisition of the temperature signal of the high-voltage motor bearing and transmission to the control unit.

[0013] The control unit includes a secondary temperature controller and a fan start / stop control box. The signal input terminal of the secondary temperature controller is connected to the spare core wire. The secondary temperature controller has a built-in temperature setting module and a relay output contact. The relay output contact is connected to the control circuit in the fan start / stop control box and is used to control the start / stop of the cooling execution unit according to the collected bearing temperature signal.

[0014] The cooling execution unit includes at least one cooling fan, which is fixedly installed on the outside of the bearing housing of the high-voltage motor bearing. The power supply terminal of the cooling fan is connected to the power output terminal of the power supply protection unit for forced air cooling of the bearing housing.

[0015] The power supply protection unit includes power circuit protection elements and control circuit protection elements, which provide working power and electrical protection for the cooling execution unit and the control unit, respectively.

[0016] In this invention, the spare wire core of the temperature sensing element is connected to the signal input terminal of the secondary temperature control instrument using a three-wire connection method.

[0017] In this invention, the upper temperature limit start value and the lower temperature limit stop value of the secondary temperature control instrument can be set independently. The upper temperature limit start value is 65°C, and the lower temperature limit stop value is 55°C.

[0018] In this invention, the fan start / stop control box is equipped with an intermediate relay and an AC contactor; the relay output contact of the secondary temperature controller is connected to the coil control circuit of the intermediate relay, the normally open auxiliary contact of the intermediate relay is connected to the coil control circuit of the AC contactor, and the main contact of the AC contactor is connected in series in the power supply circuit of the cooling fan.

[0019] In this invention, the cooling fan is mounted on the underside or side of the bearing housing via a fixed bracket, with its air outlet facing the heat dissipation surface of the bearing housing.

[0020] In this invention, two cooling fans are provided, which are respectively located at the front bearing housing and the rear bearing housing of the high-voltage motor.

[0021] In this invention, the power circuit protection element is connected in series at the power supply circuit input terminal of the cooling fan; the control circuit protection element is connected in series at the power supply circuit input terminal of the control unit.

[0022] In this invention, the secondary temperature control instrument is also equipped with an over-temperature alarm contact, which is connected to an audible and visual alarm to issue an alarm when the bearing temperature exceeds a preset alarm threshold.

[0023] The beneficial effects of this invention are:

[0024] 1. Achieves fully automatic closed-loop temperature control and cooling without manual intervention, with extremely fast response speed. This invention uses the spare core of the original temperature sensing element of the motor bearing to collect the bearing temperature in real time. Combined with a secondary temperature controller with threshold control, it realizes closed-loop control that automatically starts the fan to cool down when the temperature exceeds the limit and automatically stops running when the temperature drops. No manual on-site handling is required. The response time from exceeding the temperature limit to starting cooling is less than 1 second, which completely solves the problems of slow response and cumbersome handling in existing technologies, and is perfectly adapted to unattended working conditions.

[0025] 2. It does not damage the original structure of the high-voltage motor, resulting in low modification costs and ease of implementation. This invention directly utilizes the temperature sensing element and its spare wire core that come with the high-voltage motor bearing to collect temperature data. There is no need to drill additional holes or install new temperature sensing elements on the motor bearing housing. It does not alter the original oil baffle sealing structure of the motor, nor does it affect the normal operation of the original temperature protection circuit. On-site modification only requires wiring and fan fixing, with minimal workload. It is compatible with the vast majority of high-voltage motor equipment in operation and has extremely high versatility.

[0026] 3. Targeted and precise cooling, stable and reliable cooling effect, effectively protecting bearing health. The cooling fan of this invention is permanently installed with a fixed bracket, and the air outlet is directly facing the core heat dissipation area of ​​the bearing housing. The cooling air path is stable and highly directional. Compared with temporarily installed fans, the heat dissipation efficiency is improved by more than 50%, which can quickly reduce the bearing body temperature and effectively avoid the problem of high temperature damaging the lubricating oil film. It reduces bearing noise, vibration and accelerated wear from the root, and significantly extends the bearing service life.

[0027] 4. Comprehensive electrical design standards completely eliminate safety risks associated with temporary operations. This invention employs a fixed, permanent electrical circuit design, equipped with comprehensive short-circuit and overload protection components. All wiring is standardized and fixed, eliminating the need for operators to perform temporary wiring or live-line work such as installing fans when equipment malfunctions. This completely avoids the safety risks of electric shock and short circuits associated with temporary operations in high-voltage equipment areas, complying with relevant safety regulations for industrial sites.

[0028] 5. Significantly improves equipment operational reliability and avoids economic losses from unplanned downtime. This invention, through automatic and timely cooling control, can keep the bearing temperature within a safe operating range throughout the entire process, effectively preventing high-voltage motor overheating trips caused by excessive bearing temperature. This, in turn, eliminates unplanned downtime accidents of production units due to motor tripping, ensuring the continuous and stable operation of the production system and avoiding huge economic losses from production stoppages for enterprises. Attached Figure Description

[0029] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0030] Figure 1 This is a front view of the side structure of the automatic cooling device for high-voltage motor bearings in this embodiment;

[0031] Figure 2 This is a schematic diagram of the front structure of the automatic cooling device for the high-voltage motor bearing in this embodiment;

[0032] Figure 3 This is a schematic diagram of the rear structure of the automatic cooling device for the high-voltage motor bearing in this embodiment;

[0033] Figure 4 This is a system principle block diagram in this embodiment;

[0034] Figure 5 This is a schematic diagram of the electrical control circuit in this embodiment;

[0035] The attached diagram is labeled as follows: 1-High voltage motor, 2-Front bearing housing, 3-Rear bearing housing, 4-Temperature measuring element, 5-Spare wire core, 6-Secondary temperature control instrument, 7-Fan start / stop control box, 8-Cooling fan, 9-Fixed bracket, 10-Power circuit miniature circuit breaker, 11-Control circuit miniature circuit breaker, 12-Intermediate relay, 13-AC contactor, 14-Audible and visual alarm, 15-DCS system. Detailed Implementation

[0036] This invention provides an automatic cooling device for high-voltage motor bearings. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0037] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0038] Please see Figures 1 to 5 :

[0039] The high-voltage motor bearing automatic cooling device provided in this embodiment is applied to a 6kV high-voltage asynchronous motor in a power plant. The motor has a rated power of 2000kW and a rated speed of 1480r / min. Both the front and rear bearings are sliding bearings. Each bearing is equipped with a set of Pt100 platinum resistance thermometers 4. Each set of thermometers 4 is equipped with two sets of three-wire cores. One set of working cores is connected to the unit's DCS system 15 for real-time monitoring of bearing temperature and over-temperature trip protection. The other set is a spare core 5, which is idle and unused.

[0040] Specifically, the high-voltage motor bearing automatic cooling device of this embodiment includes a temperature acquisition unit, a control unit, a cooling execution unit, and a power supply protection unit.

[0041] The temperature acquisition unit uses the Pt100 platinum resistance thermometer 4 built into the front and rear bearings of the high-voltage motor 1. Two sets of spare cores 5 of the temperature sensing elements 4 are used. The spare cores 5 are three-wire leads. They are connected to the corresponding signal input terminals of the secondary temperature controller 6 through ZR-KVVP3×1.5mm² shielded control cables. The shielding layer is grounded at one end to eliminate electromagnetic interference on site and ensure the accuracy of temperature acquisition.

[0042] The control unit includes a secondary temperature controller 6 and a fan start / stop control box 7. The secondary temperature controller 6 is an XMTA-8000 intelligent digital display temperature controller, supporting two Pt100 signal inputs and equipped with two independent relay output contacts. It can monitor and control the temperature of the front and rear bearings separately. The temperature controller has a measurement accuracy of 0.2 class, meeting the temperature measurement accuracy requirements of industrial sites.

[0043] The fan start / stop control box 7 is fixedly installed on top of the high-voltage motor 1 to reduce the length of the control line and reduce signal interference. The electrical components deployed in the fan start / stop control box 7 include: a miniature circuit breaker 11 for the control circuit, an intermediate relay 12, and an AC contactor 13. Among them, the miniature circuit breaker 11 is a Schneider C65N2PC6A miniature circuit breaker, used for short circuit and overload protection of the control circuit; the intermediate relay 12 is an Omron HH52PAC220V intermediate relay 12, used to expand the contact capacity of the temperature controller and avoid the contact burn-out problem caused by the built-in relay of the temperature controller directly driving the contactor coil; the AC contactor 13 is a Schneider CJX2-1210AC220V AC contactor 13, used to control the power supply of the cooling fan 8.

[0044] The specific wiring method of the control circuit is as follows: The AC220V control power supply is taken from the nearest low-voltage maintenance power supply box on site. After passing through the miniature circuit breaker 11 of the control circuit, one path is connected to the power supply terminal of the secondary temperature controller 6 to provide a stable working power supply for the temperature controller; the other path is connected to the common terminal of the relay output contact of the secondary temperature controller 6. The normally open terminal of the relay output contact of the temperature controller is connected to one end of the coil of the intermediate relay 12, and the other end of the coil of the intermediate relay 12 is connected to the neutral line of the control power supply; one end of the normally open auxiliary contact of the intermediate relay 12 is connected to the live wire of the control power supply, and the other end is connected to one end of the coil of the AC contactor 13. The other end of the coil of the AC contactor 13 is connected to the neutral line of the control power supply, forming a complete start-stop control circuit.

[0045] In this embodiment, control parameters are preset in the secondary temperature controller 6: the upper limit start value of the front and rear bearing temperatures is 65°C, and the lower limit stop value is 55°C; at the same time, the over-temperature alarm threshold is set to 70°C. When the bearing temperature exceeds 70°C, the over-temperature alarm contact of the temperature controller closes and triggers the alarm.

[0046] The cooling unit comprises two industrial axial flow cooling fans 8, model SF-2.5#, rated voltage AC220V, rated power 120W, air volume 1200m³ / h, and protection rating IP54, fully adaptable to the dusty and humid operating environment of industrial sites. The two cooling fans 8 are respectively positioned corresponding to the front bearing housing 2 and rear bearing housing 3 of the high-voltage motor 1, and are fixed to the motor base by 50×50mm angle steel brackets 9. The air outlets of the cooling fans 8 face the outer heat dissipation surface of the bearing housing, with a distance of 15cm between the outlets and the bearing housing, ensuring that the cooling air directly blows onto the core area of ​​the bearing housing for precise targeted cooling. To improve cooling efficiency, heat dissipation fins 16 are provided on both the front and rear bearing housings to increase the heat dissipation area and improve the heat dissipation effect. The cooling fans 8 can blow air directly onto the bearing housing or be positioned to the side of the bearing housing. When positioned on the front, the heat dissipation fins 16 on the bearing housing have a radiating structure; when positioned to the side of the bearing housing, the heat dissipation fins 16 have a parallel arrangement.

[0047] The power circuit protection element of the power supply protection unit is a Schneider C65N2PC10A miniature circuit breaker 10. Its input terminal is connected to an AC220V low-voltage power supply, and its output terminal is connected to the main contact input terminal of an AC contactor 13. The main contact output terminal of the AC contactor 13 is connected to the power supply terminals of two cooling fans 8 respectively, providing power to the fans and realizing short circuit and overload protection of the fan power circuit.

[0048] In this embodiment, an audible and visual alarm 14 is also provided. The audible and visual alarm 14 is an industrial-grade AC220V audible and visual alarm 14, which is installed in the field equipment area. Its power supply circuit is controlled by the over-temperature alarm contact of the secondary temperature controller 6. When the bearing temperature exceeds 70°C, the over-temperature alarm contact closes, the audible and visual alarm 14 is energized, and an audible and visual alarm is issued. At the same time, the alarm signal is connected to the unit's DCS system 15 through hard wiring, and an alarm window pops up in the central control room to remind the operators to take timely action.

[0049] The working process of this embodiment is as follows:

[0050] During normal operation of the high-voltage motor 1, the Pt100 temperature sensing element 4 of the front and rear bearings collects the bearing temperature signal in real time and continuously transmits it to the secondary temperature controller 6 through the spare core 5. The temperature controller displays the operating temperature of the two bearings in real time.

[0051] When the bearing temperature rises to 65℃ due to load fluctuations, lubricating oil deterioration, or increased ambient temperature, the built-in comparison module of the secondary temperature control instrument 6 is triggered, the corresponding relay output contact closes, energizing the coil of the intermediate relay 12 in the corresponding circuit. The normally open auxiliary contact of the intermediate relay 12 closes, which in turn energizes the coil of the AC contactor 13. The main contact of the AC contactor 13 closes, the power supply of the cooling fan 8 is connected, and the fan starts running to provide forced air cooling to the bearing housing, quickly suppressing the rise in bearing temperature.

[0052] When the bearing temperature continues to drop to 55°C or below under the action of the cooling fan 8, the relay output contact corresponding to the secondary temperature control instrument 6 is disconnected, the coils of the intermediate relay 12 and the AC contactor 13 are de-energized one after another, the main contact of the AC contactor 13 is disconnected, the cooling fan 8 automatically stops running, and completes one automatic cooling cycle without any manual intervention.

[0053] If the bearing experiences a continuous abnormal temperature rise, and the temperature reaches 70℃, the over-temperature alarm contact of the secondary temperature controller 6 will close, triggering the audible and visual alarm 14. At the same time, an alarm signal will be sent to the DCS system 15 to remind operators to promptly investigate the root cause of the bearing abnormality and prevent the equipment failure from escalating.

[0054] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of the present invention.

Claims

1. An automatic cooling device for high-voltage motor bearings, characterized in that, It includes a temperature acquisition unit, a control unit, a cooling execution unit, and a power supply protection unit; The temperature acquisition unit includes a temperature sensing element integrated with the high-voltage motor bearing. The temperature sensing element is equipped with a spare wire core. The spare wire core is connected to the signal input terminal of the secondary temperature control instrument through a shielded control cable using a three-wire connection method. The shielding layer is grounded at one end and is used to acquire the temperature signal of the high-voltage motor bearing in real time and transmit it to the control unit. The control unit includes a secondary temperature controller and a fan start / stop control box. The signal input terminal of the secondary temperature controller is connected to the spare core wire. The secondary temperature controller has a built-in temperature setting module and two independent relay output contacts. The relay output contacts are connected to the control circuit in the fan start / stop control box, respectively controlling the start and stop of the cooling execution units of the front bearing housing and the rear bearing housing. The cooling execution unit includes two cooling fans, which are fixedly installed on the side of the front bearing housing and the front of the rear bearing housing respectively by a fixed bracket. The power supply terminal of the cooling fan is connected to the power output terminal of the power supply protection unit. The front and rear bearing housings are respectively provided with heat dissipation ribs. The structure of the heat dissipation ribs is adapted to the installation position of the cooling fan. The rear cooling fan blows air directly onto the rear bearing housing. The heat dissipation ribs on the rear bearing housing are of the radiating type. The front cooling fan blows air onto the side of the front bearing housing. The heat dissipation ribs on the front bearing housing are arranged in a parallel type parallel to the air blowing direction. The power supply protection unit includes power circuit protection elements and control circuit protection elements, which provide working power and electrical protection for the cooling execution unit and the control unit, respectively.

2. The automatic cooling device for high-voltage motor bearings according to claim 1, characterized in that, The upper temperature limit start value and the lower temperature limit stop value of the secondary temperature controller can be set independently. The upper temperature limit start value is 65℃, and the lower temperature limit stop value is 55℃.

3. The automatic cooling device for high-voltage motor bearings according to claim 1, characterized in that, The fan start / stop control box is equipped with an intermediate relay and an AC contactor; the relay output contact of the secondary temperature controller is connected to the coil control circuit of the intermediate relay, the normally open auxiliary contact of the intermediate relay is connected to the coil control circuit of the AC contactor, and the main contact of the AC contactor is connected in series in the power supply circuit of the cooling fan.

4. The automatic cooling device for high-voltage motor bearings according to claim 1, characterized in that, The power circuit protection element is connected in series at the power supply circuit input terminal of the cooling fan; the control circuit protection element is connected in series at the power supply circuit input terminal of the control unit.

5. The automatic cooling device for high-voltage motor bearings according to claim 1, characterized in that, The secondary temperature control instrument is also equipped with an over-temperature alarm contact, which is connected to an audible and visual alarm to issue an alarm when the bearing temperature exceeds a preset alarm threshold.

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