A method for protecting an electric motor

Abstract

This application provides a method for protecting an electric motor. A three-phase AC power supply, a forward contactor, circuit breaker A, and motor A are sequentially connected. Circuit breaker A, circuit breaker auxiliary contact A, and a reverse contactor are sequentially connected. A three-phase AC power supply, a reverse contactor, circuit breaker B, and motor B are sequentially connected. Circuit breaker B, circuit breaker auxiliary contact B, and the forward contactor are sequentially connected. When the forward contactor malfunctions, circuit breaker A is tripped. When the reverse contactor malfunctions, circuit breaker B is tripped. When circuit breaker A malfunctions, circuit breaker auxiliary contact A is tripped. When circuit breaker B malfunctions, circuit breaker auxiliary contact B is tripped. This, in turn, causes the remaining circuit components and the motor to trip and shut down. This method ensures that when the output voltage of the circuit breaker or contactor is insufficient or the current is excessive, the motor will not operate, thus protecting the motor.

Description

Technical Field

[0001] This invention relates to the field of electrical equipment protection technology, and in particular to a method for protecting electric motors. Background Technology

[0002] A circuit breaker is a control device capable of closing and opening the main control circuit and carrying load current. It automatically disconnects the circuit in the event of severe overload, short circuit, or undervoltage faults. Circuit breakers are classified into high-voltage and low-voltage circuit breakers according to their application. The most common type of circuit breaker is the low-voltage circuit breaker, whose function is to disconnect and connect load circuits, as well as to disconnect faulty circuits, preventing the escalation of accidents and ensuring the safe operation of equipment.

[0003] A contactor is a device that can quickly disconnect AC and DC main circuits and frequently connect and disconnect high-current control (up to 800A) circuits. Therefore, it is frequently used to control electric motors, and can also be used to control factory equipment, electric heaters, machine tools, and various power units and other electrical loads. Contactors not only connect and disconnect circuits, but also have low-voltage release protection. They have a large control capacity and are suitable for frequent operation and remote control. Automatic control system One of the important components in it.

[0004] Currently, in heavy industrial enterprises, circuit breakers are prone to poor contact due to prolonged use, resulting in insufficient output voltage. When the voltage is input to the motor through the contactor, the motor overheats and burns out due to severe voltage imbalance during operation. Moreover, a single motor in a large enterprise typically costs around 10,000 yuan, making it very expensive.

[0005] When the output voltage of the circuit breaker is insufficient, or the contacts of the contactor wear and become poor due to prolonged engagement and disengagement, the input voltage of the motor becomes unstable, leading to a motor burnout accident. Insufficient output voltage of the circuit breaker or contactor will cause the equipment to operate with a single phase. Large enterprises typically have equipment costing over 10,000 yuan, making it expensive. At the same time, replacing the motor is time-consuming and labor-intensive, requiring at least two people and taking two hours or even longer. Summary of the Invention

[0006] The purpose of this invention is to provide a method for protecting electric motors.

[0007] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows:

[0008] A method for protecting an electric motor, wherein the power supply line of a three-phase AC power supply is electrically connected to the input terminal of a forward contactor, the output terminal of the forward contactor is electrically connected to the input terminal of a circuit breaker A via a conductive wire, and the output terminal of the circuit breaker A is electrically connected to the input terminal of an electric motor A via a conductive wire.

[0009] The circuit breaker A is provided with a circuit breaker auxiliary contact A. The handle of the circuit breaker A and the handle of the circuit breaker auxiliary contact A move in unison. The circuit breaker A and the circuit breaker auxiliary contact A disconnect at the same time, or the circuit breaker A and the circuit breaker auxiliary contact A connect at the same time. The other output terminal of the circuit breaker A is electrically connected to the input terminal of the circuit breaker auxiliary contact A through a conductive wire. The output terminal of the circuit breaker auxiliary contact A is electrically connected to the input terminal of the reversing contactor through a conductive wire.

[0010] The power supply line of the three-phase AC power supply is electrically connected to the input terminal of the reverse contactor. The output terminal of the reverse contactor is electrically connected to the input terminal of circuit breaker B through a conductive wire. The output terminal of circuit breaker B is electrically connected to the input terminal of motor B through a conductive wire.

[0011] The circuit breaker B is equipped with an auxiliary contact B. The handle of the circuit breaker B and the handle of the auxiliary contact B move in unison. The circuit breaker B and the auxiliary contact B can simultaneously disconnect or simultaneously close. The other output terminal of the circuit breaker B is electrically connected to the input terminal of the auxiliary contact B via a conductive wire. The output terminal of the auxiliary contact B is electrically connected to the input terminal of the forward contactor via a conductive wire.

[0012] Preferably, circuit breaker A has over-voltage, under-voltage and over-current protection functions. When the forward contactor malfunctions, causing under-voltage, over-voltage or over-current in the output voltage, circuit breaker A will trip. When circuit breaker A trips, the forward contactor, circuit breaker auxiliary contact A, motor A, reverse contactor, circuit breaker B, circuit breaker auxiliary contact B and motor B will all trip, lose power and stop.

[0013] Circuit breaker B has over-voltage, under-voltage, and over-current protection functions. When the reverse contactor malfunctions, causing under-voltage, over-voltage, or over-current in the output voltage, circuit breaker B will trip. When circuit breaker B trips, the forward contactor, circuit breaker A, circuit breaker auxiliary contact A, motor A, reverse contactor, circuit breaker auxiliary contact B, and motor B will all trip, lose power, and stop.

[0014] Preferably, the circuit breaker auxiliary contact A has over-voltage, under-voltage and over-current protection functions. When the circuit breaker A malfunctions, causing under-voltage, over-voltage or over-current in the output voltage, the circuit breaker auxiliary contact A will open. When the circuit breaker auxiliary contact A opens, the forward contactor, circuit breaker A, motor A, reverse contactor, circuit breaker B, circuit breaker auxiliary contact B and motor B will all be disconnected, de-energized and shut down.

[0015] The circuit breaker auxiliary contact B has over-voltage, under-voltage, and over-current protection functions. When the circuit breaker B malfunctions, causing under-voltage, over-voltage, or over-current in the output voltage, the circuit breaker auxiliary contact B will open. When the circuit breaker auxiliary contact B opens, the forward contactor, circuit breaker A, circuit breaker auxiliary contact A, motor A, reverse contactor, circuit breaker B, and motor B will all be disconnected, de-energized, and shut down.

[0016] This application provides a method for protecting an electric motor. When the forward contactor malfunctions, causing undervoltage, overvoltage, or overcurrent in the output voltage, circuit breaker A is tripped. When circuit breaker A trips, the forward contactor, circuit breaker auxiliary contact A, motor A, reverse contactor, circuit breaker B, circuit breaker auxiliary contact B, and motor B are all tripped, de-energized, and shut down.

[0017] When the reverse contactor malfunctions, causing undervoltage, overvoltage, or overcurrent in the output voltage, circuit breaker B will trip. When circuit breaker B trips, the forward contactor, circuit breaker A, circuit breaker auxiliary contact A, motor A, reverse contactor, circuit breaker auxiliary contact B, and motor B will all trip, lose power, and stop.

[0018] When circuit breaker A malfunctions, causing undervoltage, overvoltage, or overcurrent in the output voltage, the auxiliary contact A of the circuit breaker will open. When the auxiliary contact A of the circuit breaker opens, the forward contactor, circuit breaker A, motor A, reverse contactor, circuit breaker B, auxiliary contact B of the circuit breaker, and motor B will all be disconnected, de-energized, and shut down.

[0019] When circuit breaker B malfunctions, causing undervoltage, overvoltage, or overcurrent in the output voltage, the auxiliary contact B of the circuit breaker will open. When the auxiliary contact B of the circuit breaker opens, the forward contactor, circuit breaker A, auxiliary contact A of the circuit breaker, motor A, reverse contactor, circuit breaker B, and motor B will all be disconnected, de-energized, and shut down.

[0020] This ensures that when the output voltage of the circuit breaker or contactor is insufficient or the current is excessive, the motor can be prevented from operating, thus protecting the motor, effectively preventing faults, greatly improving the safety of motors and other equipment, and reducing the occurrence of faults. Attached Figure Description

[0021] Figure 1 A schematic diagram illustrating the working principle of a method for protecting an electric motor provided in an embodiment of this application ( Figure 1 The arrows in the diagram indicate the direction of the current. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] This application provides a method for protecting an electric motor, wherein the power supply line of a three-phase AC power supply is electrically connected to the input terminal of a forward contactor, the output terminal of the forward contactor is electrically connected to the input terminal of a circuit breaker A through a conductive wire, and the output terminal of the circuit breaker A is electrically connected to the input terminal of an electric motor A through a conductive wire.

[0024] The circuit breaker A is provided with a circuit breaker auxiliary contact A. The handle of the circuit breaker A and the handle of the circuit breaker auxiliary contact A move in unison. The circuit breaker A and the circuit breaker auxiliary contact A disconnect at the same time, or the circuit breaker A and the circuit breaker auxiliary contact A connect at the same time. The other output terminal of the circuit breaker A is electrically connected to the input terminal of the circuit breaker auxiliary contact A through a conductive wire. The output terminal of the circuit breaker auxiliary contact A is electrically connected to the input terminal of the reversing contactor through a conductive wire.

[0025] The power supply line of the three-phase AC power supply is electrically connected to the input terminal of the reverse contactor. The output terminal of the reverse contactor is electrically connected to the input terminal of circuit breaker B through a conductive wire. The output terminal of circuit breaker B is electrically connected to the input terminal of motor B through a conductive wire.

[0026] The circuit breaker B is equipped with an auxiliary contact B. The handle of the circuit breaker B and the handle of the auxiliary contact B move in unison. The circuit breaker B and the auxiliary contact B can simultaneously disconnect or simultaneously close. The other output terminal of the circuit breaker B is electrically connected to the input terminal of the auxiliary contact B via a conductive wire. The output terminal of the auxiliary contact B is electrically connected to the input terminal of the forward contactor via a conductive wire.

[0027] In one embodiment of this application, circuit breaker A has over-voltage, under-voltage and over-current protection functions. When the forward contactor malfunctions, causing under-voltage, over-voltage or over-current in the output voltage, circuit breaker A will trip. When circuit breaker A trips, the forward contactor, circuit breaker auxiliary contact A, motor A, reverse contactor, circuit breaker B, circuit breaker auxiliary contact B and motor B will all trip, lose power and stop.

[0028] Circuit breaker B has over-voltage, under-voltage, and over-current protection functions. When the reverse contactor malfunctions, causing under-voltage, over-voltage, or over-current in the output voltage, circuit breaker B will trip. When circuit breaker B trips, the forward contactor, circuit breaker A, circuit breaker auxiliary contact A, motor A, reverse contactor, circuit breaker auxiliary contact B, and motor B will all trip, lose power, and stop.

[0029] In one embodiment of this application, the circuit breaker auxiliary contact A has over-voltage, under-voltage and over-current protection functions. When the circuit breaker A malfunctions, causing under-voltage, over-voltage or over-current in the output voltage, the circuit breaker auxiliary contact A is disconnected. When the circuit breaker auxiliary contact A is disconnected, the forward contactor, circuit breaker A, motor A, reverse contactor, circuit breaker B, circuit breaker auxiliary contact B and motor B are all disconnected, de-energized and shut down.

[0030] The circuit breaker auxiliary contact B has over-voltage, under-voltage, and over-current protection functions. When the circuit breaker B malfunctions, causing under-voltage, over-voltage, or over-current in the output voltage, the circuit breaker auxiliary contact B will open. When the circuit breaker auxiliary contact B opens, the forward contactor, circuit breaker A, circuit breaker auxiliary contact A, motor A, reverse contactor, circuit breaker B, and motor B will all be disconnected, de-energized, and shut down.

[0031] The circuit breaker in this application has over / under voltage and overcurrent protection functions: Over / under voltage trip unit: The fully automatic over / under voltage delay protector is reasonably designed and can quickly and reliably switch the power supply under high voltage impact and undervoltage conditions to protect household appliances. When the voltage returns to normal, it can automatically connect the circuit and restore the power supply after a delay. It can effectively protect appliances from the impact of instantaneous power supply. All functions are fully automated and do not require special personnel to operate. It uses a dual-color LED indicator for safety and speed.

[0032] Overcurrent protection: Overcurrent protection is a trip unit that trips the switch when the current exceeds the actual predetermined value. It can be selected according to the actual power value of the motor. When the current of the motor and other electrical appliances exceeds the rated current, it can effectively trip the switch and ensure the inherent safety of the equipment.

[0033] In this application, the circuit breaker auxiliary contacts are contacts mechanically linked to the circuit breaker's main circuit opening and closing mechanism. They are primarily used to indicate the circuit breaker's open and closed status and are connected to the circuit breaker's control circuit to control or interlock related electrical components through the circuit breaker's opening and closing. In this application, the circuit breaker auxiliary contacts are linked to the circuit breaker; the circuit breaker auxiliary contacts and the circuit breaker simultaneously open the circuit, or simultaneously close the circuit.

[0034] Existing circuit breakers are typically directly connected to the contactor's upper port. The contactor is controlled to open and close by pressing a button via a control circuit. This application connects auxiliary contacts to the side of the load circuit breaker, inserting the contactor control circuit into the normally open position of the auxiliary contacts. When the circuit breaker is closed, the normally open contact of the connected auxiliary contacts is closed, allowing for immediate control of equipment operation. When the load circuit breaker experiences phase loss or tripping, its normally open contact changes from normally closed to normally open, disconnecting the main contactor control circuit. If the operator fails to detect the problem in time, regardless of their actions, other equipment controlled by this system will be unable to operate, thus ensuring the basic safety of other normal equipment and effectively preventing the escalation of damage from the fault.

[0035] The methods and apparatus not described in detail in this invention are all prior art and will not be elaborated further.

[0036] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A method for protecting an electric motor, characterized in that, The power supply line of the three-phase AC power supply is electrically connected to the input terminal of the forward contactor. The output terminal of the forward contactor is electrically connected to the input terminal of circuit breaker A through a conductive wire. The output terminal of circuit breaker A is electrically connected to the input terminal of motor A through a conductive wire. The circuit breaker A is provided with a circuit breaker auxiliary contact A. The handle of the circuit breaker A and the handle of the circuit breaker auxiliary contact A move in unison. The circuit breaker A and the circuit breaker auxiliary contact A disconnect at the same time, or the circuit breaker A and the circuit breaker auxiliary contact A connect at the same time. The other output terminal of the circuit breaker A is electrically connected to the input terminal of the circuit breaker auxiliary contact A through a conductive wire. The output terminal of the circuit breaker auxiliary contact A is electrically connected to the input terminal of the reversing contactor through a conductive wire. The power supply line of the three-phase AC power supply is electrically connected to the input terminal of the reverse contactor. The output terminal of the reverse contactor is electrically connected to the input terminal of circuit breaker B through a conductive wire. The output terminal of circuit breaker B is electrically connected to the input terminal of motor B through a conductive wire. The circuit breaker B is provided with a circuit breaker auxiliary contact B. The handle of the circuit breaker B and the handle of the circuit breaker auxiliary contact B move in unison. The circuit breaker B and the circuit breaker auxiliary contact B can simultaneously disconnect or simultaneously close. The other output terminal of the circuit breaker B is electrically connected to the input terminal of the circuit breaker auxiliary contact B through a conductive wire. The output terminal of the circuit breaker auxiliary contact B is electrically connected to the input terminal of the forward contactor through a conductive wire. Circuit breaker A has over-voltage, under-voltage and over-current protection functions. When the forward contactor operates abnormally, resulting in under-voltage, over-voltage or over-current output voltage, circuit breaker A will trip. When circuit breaker A trips, the forward contactor, circuit breaker auxiliary contact A, motor A, reverse contactor, circuit breaker B, circuit breaker auxiliary contact B and motor B will all trip, lose power and stop. Circuit breaker B has over-voltage, under-voltage and over-current protection functions. When the reverse contactor operates abnormally, resulting in under-voltage, over-voltage or over-current output voltage, circuit breaker B will trip. When circuit breaker B trips, the forward contactor, circuit breaker A, circuit breaker auxiliary contact A, motor A, reverse contactor, circuit breaker auxiliary contact B and motor B will all trip, lose power and stop. The circuit breaker auxiliary contact A has over-voltage, under-voltage and over-current protection functions. When the circuit breaker A malfunctions, resulting in under-voltage, over-voltage or over-current output voltage, the circuit breaker auxiliary contact A will open. When the circuit breaker auxiliary contact A opens, the forward contactor, circuit breaker A, motor A, reverse contactor, circuit breaker B, circuit breaker auxiliary contact B and motor B will all be disconnected, de-energized and shut down. The circuit breaker auxiliary contact B has over-voltage, under-voltage, and over-current protection functions. When the circuit breaker B malfunctions, causing under-voltage, over-voltage, or over-current in the output voltage, the circuit breaker auxiliary contact B will open. When the circuit breaker auxiliary contact B opens, the forward contactor, circuit breaker A, circuit breaker auxiliary contact A, motor A, reverse contactor, circuit breaker B, and motor B will all be disconnected, de-energized, and shut down.

Images