Motor stalling protection circuit and device for ultraviolet cleaning mechanism

Abstract

The utility model relates to the field of motor stalling protection of an ultraviolet cleaning mechanism, in particular to a motor stalling protection circuit and device of an ultraviolet cleaning mechanism, which comprises a thermomagnetic motor protection switch electrically connected with a motor and used for protecting the motor; the two ends of the motor forward rotation circuit are electrically connected with the thermomagnetic motor protection switch and the motor respectively, and the motor forward rotation circuit is located between the thermomagnetic motor protection switch and the motor and used for controlling forward rotation of the motor; the forward rotation switch is arranged on the motor forward rotation circuit; the two ends of the motor reverse rotation circuit are electrically connected with the thermomagnetic motor protection switch and the motor respectively, and the motor reverse rotation circuit is located between the thermomagnetic motor protection switch and the motor, connected with the motor forward rotation circuit in parallel and used for controlling reverse rotation of the motor; and the reverse switch is arranged on the motor reverse circuit. When the ultraviolet cleaning mechanism driven by the motor is locked, the motor locked-rotor protection circuit can perform quick tripping protection, so that a motor winding is prevented from being overheated, and a quartz sleeve is prevented from being damaged due to continuous rotation or lateral torque.

Description

Technical Field

[0001] The present application relates to the field of motor stall protection for ultraviolet cleaning mechanisms, and in particular to a motor stall protection circuit and device for ultraviolet cleaning mechanisms. Background Art

[0002] The flow-through or open channel UV device has one or more quartz tubes, which contain UV lamps. The quartz tubes have the function of isolating liquid (usually water) to protect the UV lamps and transmit UV rays. When sewage or water with high calcium and magnesium ion content, or water with high temperature and high organic matter flows through the UV device, it is easy to precipitate, adhere or even scale on the quartz tubes, which makes it impossible for the UV rays to be fully transmitted, greatly reducing the UV treatment effect.

[0003] In order to ensure the transmission of ultraviolet rays and extend the service life of the equipment, there are two main types of automatic cleaning solutions for ultraviolet equipment: one is pneumatic or hydraulic drive; the other is motor drive. For example, Chinese utility model patent 201120066975.6 discloses a pneumatic cleaning device for a flow-through ultraviolet disinfector, including a cylinder, a barrel, a cleaning disc, etc. In actual use, an air source needs to be provided and the stroke of the cylinder piston rod will exceed the length of the barrel, increasing the equipment footprint. The invention only involves the structure but not the protection mechanism. In contrast, Chinese utility model patent 201620367907.6 discloses an automatic cleaning ultraviolet filter device for cleaning the surface of a quartz sleeve. Mechanical automatic cleaning driven by a motor is a commonly used online cleaning method for quartz sleeves in flow-through or open channel ultraviolet devices. Mechanical automatic cleaning driven by a motor usually consists of a motor, a coupling, a bearing, a seal, a transmission screw or screw, a transmission nut, a cleaning disc, a cleaning ring or (brush), a power supply device, and a limit sensor. However, the wall thickness of the quartz sleeve is 1.5mm or 2mm, and the length ranges from 100mm to 2000mm or even longer, so the quartz sleeve can withstand less force. During cleaning, there is a rotational or lateral torque acting on the quartz sleeve. In particular, the ultraviolet equipment with one lamp tube has an unbalanced unilateral distance between the quartz sleeve and the drive screw, which will aggravate the effect of the torque. When, for example, the limit sensor fails, the cleaning exceeds the stroke and hits the machine, or the quartz sleeve is thickly scaled, the motor torque is insufficient to drive the cleaning mechanism, or there are foreign objects (such as quartz sand and filter sand that leak into the device from the front end) inside the device, causing the cleaning mechanism to get stuck, etc., the motor is in a stalled state. There is a risk of the motor heating up rapidly and the windings burning out, and the quartz sleeve is constantly subject to the action of rotation or lateral torque and is broken.

[0004] To address this problem, domestic and foreign ultraviolet peers have selected motors with 120℃ thermal protection. The motors with thermal protection are equipped with a temperature control switch. The temperature control switch is a bimetallic sensor composed of two pieces of metal with different expansion coefficients stuck together. It will be disconnected or attracted as the temperature changes. When the motor is blocked and the winding temperature reaches 120℃, the power supply will be automatically disconnected, and the power supply will be automatically connected when the temperature is lower than 120℃.

[0005] Existing motor stall protection technology, such as China Invention Patent 202110645382.3, discloses a motor stall protection method using current and speed dual criteria. A speed feedback module and a current feedback module are installed on the motor, and the data information collected by the speed feedback module and the current feedback module are compared with the preset standard information, and the running status of the motor is determined according to the comparison result and sent to the computer monitoring system.

[0006] Chinese invention patent 202210618783.4 discloses a motor stall detection method and detection device, which obtains the current speed of the motor and the current value of the motor's output power, torque or q-axis current; matches the current speed with the current value, and determines whether the motor is stalled based on the matching result.

[0007] Chinese invention patent 202210456036.5 discloses a motor stall protection circuit, a motor control system and a method, wherein a switch module is used to receive a first level signal outputted by an enable end of a microcontroller unit, and is also used to receive voltage signals from two output ends of a motor position sensor. When the first level signal is a high level signal or the voltage signal is an AC signal, the enable module is controlled to turn on the motor for operation. When the first level signal is a low level signal and the voltage signal is a DC signal, the enable module is controlled to turn off the motor for operation.

[0008] Chinese invention patent 202310992665.4 discloses a motor stall protection control method, device, motor controller and storage medium. The method detects the current speed regulation signal voltage of the motor in real time, and compares the current speed regulation signal voltage with the preset current limiting voltage; when the current speed regulation signal voltage is lower than the preset current limiting voltage, the current flux value of the motor is obtained; the current flux value is compared with the preset real flux value, and whether the stall protection is triggered is determined according to the comparison result; when the current speed regulation signal voltage is higher than or equal to the preset current limiting voltage, the current voltage synthesis vector of the motor is obtained; the current voltage synthesis vector is compared with the preset voltage synthesis vector, and whether the stall protection is triggered is determined according to the comparison result.

[0009] Chinese utility model patent 201821519669.1 discloses a three-phase motor stall protection circuit, which involves a three-phase motor stall protection circuit, including a speed relay KS, a contactor KM, a time relay KT, a stop button SB1, and a start button SB2. The speed relay KS is selected to monitor the stall state of the three-phase motor rotor, and the rotor of KS is coaxially connected with the rotor of the three-phase motor, and the two forward and reverse normally open switches of KS are connected in parallel at both ends of the KT delayed disconnect switch. If the motor is stalled, the contactor KM is controlled to reset by the combined action of the speed relay KS and the time relay KT, and the three-phase power supply of the main circuit is cut off, and the motor is also powered off and stopped to prevent the motor from burning.

[0010] In the prior art, when there is no one on duty or the inspection fails to find the motor with thermal protection, the motor repeatedly connects and disconnects the power supply, and the bimetallic contacts are prone to sparks for strong inductive loads, so after multiple switches, the contacts are prone to sticking or resistance increases. In addition, through testing, it was found that: taking a 40W 220V 50Hz motor as an example, the room temperature is 24.6℃, and the time required for the simulated loading to the motor stalling moment when the motor winding temperature is 71.5℃ is 3 hours and 3 minutes. After stalling, it takes 42 minutes for the temperature to rise to 120℃, and the protection time is relatively long. It does not fundamentally solve the risks of motor winding heating and quartz sleeve damage due to stress, and the price of motors with thermal protection is relatively high.

[0011] Other methods to prevent stalling are to monitor the motor current, speed, position signal or speed control voltage signal, flux value and compare them with pre-set values ​​through controller and program. Corresponding detection sensors and controllers must be installed on the equipment, and writing corresponding programs, structures and logic is not only complex but also costly.

[0012] Since the installation environment of UV equipment is relatively humid and the installation space is small, usually the diameter of the pipeline does not have extra space to install other accessories except the motor. On the basis of the original program controlling the operation of the motor or the motor with thermal protection, a low-cost, small-sized, easy-to-install, and fast-response hardware protection device is sought to fundamentally solve the problem of electronic stall winding burnout or quartz sleeve damage due to stress. Summary of the invention

[0013] In order to better protect the motor of the ultraviolet cleaning mechanism, the present application provides a motor stall protection circuit and device for the ultraviolet cleaning mechanism. When the ultraviolet cleaning mechanism driven by the motor stalls, the stall protection circuit in the present application can quickly trip for protection, preventing the motor winding from overheating and avoiding the quartz sleeve from being damaged by continuous rotation or lateral torque.

[0014] In the first aspect, the present application provides a UV cleaning mechanism motor stall protection circuit, which adopts the following technical solution:

[0015] A motor stall protection circuit for an ultraviolet cleaning mechanism, comprising:

[0016] A thermal magnetic motor protection switch is electrically connected to the motor and is used to protect the motor;

[0017] The motor forward rotation circuit has two ends electrically connected to the thermal magnetic motor protection switch and the motor respectively, and is located between the thermal magnetic motor protection switch and the motor, and is used to control the motor forward rotation;

[0018] The forward switch is arranged on the forward circuit of the motor;

[0019] The motor reversing circuit has two ends electrically connected to the thermal-magnetic motor protection switch and the motor respectively, is located between the thermal-magnetic motor protection switch and the motor, and is connected in parallel with the motor forward rotation circuit to control the motor reversing;

[0020] The reverse switch is arranged on the motor reverse circuit.

[0021] Preferably, a motor protection capacitor is provided on the motor, and two ends of the motor protection capacitor are electrically connected to the motor forward rotation circuit and the motor reverse rotation circuit respectively.

[0022] Preferably, the thermal-magnetic motor protection switch comprises a circuit breaker protection switch and a variable resistor, and the circuit breaker protection switch and the variable resistor are electrically connected.

[0023] In a second aspect, the present application provides a motor stall protection device for an ultraviolet cleaning mechanism, which adopts the following technical solution:

[0024] A motor stall protection device for an ultraviolet cleaning mechanism comprises the above-mentioned motor stall protection circuit for an ultraviolet cleaning mechanism.

[0025] In summary, this application includes the following beneficial technical effects:

[0026] 1. The motor power supply in this application utilizes a thermal magnetic motor protection switch, so that the switch must be manually reset after it trips. When the ultraviolet cleaning mechanism driven by the motor is blocked, the motor blocking protection circuit in this application can quickly trip to protect against overheating of the motor winding and damage to the quartz sleeve caused by continuous rotation or lateral torque.

[0027] 2. The present invention proposes a motor stall protection device, which monitors the motor current through a thermal-magnetic motor protection switch with a set thermal protection current. When the motor stalls, the winding heats up and the motor current rises. After exceeding the set thermal protection current, the thermal-magnetic motor protection switch trips for protection in a short time (it must be reset manually after tripping), causing the motor to lose power and stop moving, thereby avoiding burning of the motor winding and preventing the quartz sleeve from being broken due to long-term rotation or lateral torque. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of a circuit according to an embodiment of the present application.

[0029] Figure 2 It is an example diagram in the embodiment of the present application.

[0030] Explanation of the reference numerals: Q2, thermal-magnetic motor protection switch; S1, motor forward rotation circuit; S2, motor reverse rotation circuit; K1, forward rotation switch; K2, reverse rotation switch; C1, motor protection capacitor; M1, motor. DETAILED DESCRIPTION

[0031] The present application is further described in detail below in conjunction with the accompanying drawings.

[0032] The embodiment of the present application discloses a motor stall protection circuit for an ultraviolet cleaning mechanism.

[0033] Reference Figure 1 The motor stall protection circuit of the ultraviolet cleaning mechanism includes a thermal magnetic motor protection switch Q2, a motor forward rotation circuit S1, a forward rotation switch K1, a motor reverse rotation circuit S2, and a reverse rotation switch K2.

[0034] The thermal-magnetic motor protection switch Q2 includes a circuit breaker and a variable resistor, wherein the resistance of the variable resistor can be manually adjusted to adjust the current flowing through the motor stall protection circuit. The variable resistor can also be a component capable of resistance adjustment, such as a micro resistor box. In this embodiment, the thermal-magnetic motor protection switch Q2 can be used for unidirectional and three-phase power supply, and its circuit breaker protection switch can be used in a button type or a knob type. At the same time, the thermal current of the thermal-magnetic motor protection switch can also be divided into several gears, such as 0.1A-0.16A, 0.16A-0.25A, 0.25A-0.4A, 0.4-0.63A, 0.63-1A, etc.

[0035] Reference Figure 1 The two ends of the motor forward rotation circuit S1 are electrically connected to the thermal magnetic motor protection switch Q2 and the motor M1 respectively. The forward rotation switch K1 is arranged on the motor forward rotation circuit S1. The motor forward rotation circuit S1 is used to control the forward rotation of the motor M1. The forward rotation switch K1 is used to control the on and off of the motor forward rotation circuit S1. The forward rotation switch K1 is a relay.

[0036] The two ends of the motor reversal circuit S2 are electrically connected to the thermal magnetic motor protection switch Q2 and the motor M1 respectively. The reversal switch K2 is arranged on the motor reversal circuit S2. The motor reversal circuit S2 is used to control the reversal of the motor M1. The motor reversal circuit S2 is connected to the motor forward circuit S1. The reversal switch K2 is used to control the on and off of the motor reversal circuit S2. The reversal switch K2 uses a relay.

[0037] Reference Figure 1 The ultraviolet cleaning mechanism motor stall protection circuit also includes a motor protection capacitor C1, and the two ends of the motor protection capacitor C1 are electrically connected to the motor forward circuit S1 and the motor reverse circuit S2 respectively. And the connection point between the motor protection capacitor C1 and the motor forward circuit S1 is located between the forward switch K1 and the motor M1, and the connection point between the motor protection capacitor C1 and the motor reverse circuit S2 is located between the reverse switch K2 and the motor M1.

[0038] Specifically, taking the motor protection capacitor C1 as 2.5uf 450V, the motor model as 5IK40GN-C 40W220V 50Hz motor, the motor protection switch NS2-25 (0.25), the protection current as 0.25A, the normal operation current of the motor not exceeding 0.2A, the channel 08 monitoring the motor winding temperature, and the room temperature as 25℃ as an example, the motor stall protection circuit of the ultraviolet cleaning mechanism is tested, and the test results are as follows Figure 2 The first stall protection was between 17:29 and 17:31. The thermal-magnetic motor protection switch was activated within 1 minute after the stall. The maximum stall current was 0.256A. After cooling, it was manually reset for the next stall. Effective protection was achieved for 10 consecutive stalls, and the maximum winding temperature was less than 50°C.

[0039] The embodiment of the present application further discloses a motor stall protection device for an ultraviolet cleaning mechanism, which includes a motor stall protection circuit for an ultraviolet cleaning mechanism disclosed in the above embodiment.

[0040] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A motor stall protection circuit for an ultraviolet cleaning mechanism, characterized in that: include: A thermal magnetic motor protection switch is electrically connected to the motor and is used to protect the motor; The motor forward rotation circuit has two ends electrically connected to the thermal magnetic motor protection switch and the motor respectively, and is located between the thermal magnetic motor protection switch and the motor, and is used to control the motor forward rotation; The forward switch is arranged on the forward circuit of the motor; The motor reversing circuit has two ends electrically connected to the thermal-magnetic motor protection switch and the motor respectively, is located between the thermal-magnetic motor protection switch and the motor, and is connected in parallel with the motor forward rotation circuit to control the motor reversing; The reverse switch is arranged on the motor reverse circuit.

2. The ultraviolet cleaning mechanism motor stall protection circuit according to claim 1, characterized in that: The motor is provided with a motor protection capacitor, and two ends of the motor protection capacitor are electrically connected to the motor forward rotation circuit and the motor reverse rotation circuit respectively.

3. The ultraviolet cleaning mechanism motor stall protection circuit according to claim 1, characterized in that: The thermal-magnetic motor protection switch comprises a circuit breaker protection switch and a variable resistor, and the circuit breaker protection switch and the variable resistor are electrically connected.

4. A motor stall protection device for an ultraviolet cleaning mechanism, characterized in that: The invention comprises a motor stall protection circuit for an ultraviolet cleaning mechanism as claimed in any one of claims 1 to 3.

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