Anti-interference motor protector

Abstract

The anti-interference motor protector comprises a housing, three magnetic rings and a PCB, the three magnetic rings respectively comprise pins, the three magnetic rings are respectively formed through the three pins and are welded on the PCB, the PCB comprises three wiring lines with the same wiring length, and the three wiring lines with the same wiring length are welded on the PCB through the three wiring lines with the same wiring length. The three magnetic rings of the motor protector are ensured to be the same in wavelength when the radio frequency equipment approaches, so that the phenomenon that as the design of an internal circuit of an existing motor protector is unreliable, the wavelength input into the motor protector enters and exits when the radio frequency equipment senses signals due to the fact that the three magnetic rings sense the signals, and the motor protector is not reliable in design is avoided. Therefore, the motor protector is interfered, and the alarm signal jumps at random such as overload, phase loss, locked-rotor or underload.

Description

Technical Field

[0001] The utility model relates to the technical field of motor protectors, in particular to an anti-interference motor protector. Background Art

[0002] A motor protector is a protector device used to provide alarm or protection control for a motor when it encounters situations such as overload, open phase, locked rotor, or underload. Most existing motor protectors are used by connecting them between an AC contactor and a motor. That is, the three-phase live wires A, B, and C led out from a three-phase circuit breaker are connected to the AC contactor first, and then before being connected to the motor, they are first connected to the motor protector and then to the motor, so as to achieve the protection of the motor.

[0003] For some motor protectors that have been used, due to different usage conditions or environments, in some cases, the motor protector may come into contact with radio frequency devices such as pagers. That is, when a radio frequency device appears within about 1 meter of the motor protector, the motor protector may be interfered by signals because the two are in the same frequency band, resulting in chaotic situations, such as overload, open phase, locked rotor, or underload alarm phenomena on the motor protector, and arbitrary jumping, which greatly affects the use and reliability of the motor protector. Summary of the Invention

[0004] In view of the above deficiencies, the utility model provides a motor protector that can prevent being affected by radio frequency devices such as pagers during use.

[0005] To achieve the above objectives, the utility model adopts an anti-interference motor protector, which includes a housing, three magnetic rings arranged in the housing for the external A, B, and C three-phase live wires to pass through respectively, and a PCB board arranged in the housing. Each of the three magnetic rings includes pins, and the three magnetic rings are respectively formed by the three pins and welded to the PCB board. The PCB board includes three wiring lines correspondingly connected to the three magnetic rings, and the wiring lengths of the three wiring lines are the same. Through the three wiring lines with the same wiring length, the internal part of the PCB board can be connected to the three magnetic rings through standard differential signals, and the standard differential signal output of the PCB board is stable.

[0006] The utility model is further arranged such that the three wiring lines include two outer lines distributed on both sides and an intermediate line distributed between the two outer lines. The two outer lines are in an oblique structure, and the intermediate line is in a curved distribution.

[0007] The utility model is further configured such that the PCB board includes a control circuit, and the control circuit includes a current sampling circuit and a single-phase metering chip U1. The single-phase metering chip U1 includes pins V1P, V1N, V2P, V2N, V3P, and V3N for inputting the sampled current into the chip. The current sampling circuit includes a phase A current sampling circuit, a phase B current sampling circuit, and a phase C current sampling circuit;

[0008] The phase A current sampling circuit includes a terminal block CN1, resistors R1, R2, R5, R6, capacitors C1, C7. The pin 2 of the terminal block CN1 is respectively connected to one end of the resistor R1 and one end of the resistor R2. The other end of the resistor R1 is respectively connected to one end of the capacitor C1 and the pin V3N of the single-phase metering chip U1. The pin 1 of the terminal block CN1 is respectively connected to one end of the resistor R5 and one end of the resistor R6. The other end of the resistor R6 is respectively connected to one end of the capacitor C7 and the pin V3P of the single-phase metering chip U1. The other end of the resistor R2 and the other end of the resistor R5 are commonly grounded. The other end of the capacitor C1 and the other end of the capacitor C7 are commonly grounded. And the wiring length from the resistor R2 to the pin V3N of the single-phase metering chip U1 in the phase A current sampling circuit is equal to the wiring length from the resistor R5 to the pin V3P of the single-phase metering chip U1;

[0009] The phase B current sampling circuit includes a terminal block CN2, resistors R7, R8, R11, R13, capacitors C16, C17. The pin 2 of the terminal block CN2 is respectively connected to one end of the resistor R7 and one end of the resistor R8. The other end of the resistor R7 is respectively connected to one end of the capacitor C16 and the pin V1N of the single-phase metering chip U1. The pin 1 of the terminal block CN2 is respectively connected to one end of the resistor R11 and one end of the resistor R13. The other end of the resistor R13 is respectively connected to one end of the capacitor C13 and the pin V1P of the single-phase metering chip U1. The other end of the resistor R8 and the other end of the resistor R11 are commonly grounded. The other end of the capacitor C16 and the other end of the capacitor C17 are commonly grounded. And the wiring length from the resistor R8 to the pin V1N of the single-phase metering chip U1 in the phase B current sampling circuit is equal to the wiring length from the resistor R11 to the pin V1P of the single-phase metering chip U1;

[0010] The described C-phase current sampling circuit includes a wiring terminal CN3, resistors R14 - R17, capacitors C18, C23. The pin 2 of the wiring terminal CN3 is respectively connected to one end of the resistor R14 and one end of the resistor R15. The other end of the resistor R14 is respectively connected to one end of the capacitor C18 and the pin V2N of the single-phase metering chip U1. The pin 1 of the wiring terminal CN2 is respectively connected to one end of the resistor R16 and one end of the resistor R17. The other end of the resistor R17 is respectively connected to one end of the capacitor C23 and the pin V2P of the single-phase metering chip U1. The other end of the resistor R15 and the other end of the resistor R16 are commonly connected to the ground terminal. The other end of the capacitor C18 and the other end of the capacitor C23 are commonly connected to the ground terminal. And in the C-phase current sampling circuit, the wiring length from the resistor R15 to the pin V2N of the single-phase metering chip U1 is equal to the wiring length from the resistor R15 to the pin V2P of the single-phase metering chip U1.

[0011] Compared with the prior art, the beneficial effects of the present utility model are as follows: When designing the wiring circuits of the three magnetic rings respectively penetrated by the A, B, and C-phase live wires on the internal PCB board of the motor protector, for the three wiring circuits that respectively connect the three magnetic rings to the inside of the PCB, and at the same time, these three wiring lengths are the same. Thus, when the motor protector works, through the action of the standard differential signal inside the PCB board, it can be ensured that when a radio frequency device approaches, the wavelengths induced by the three magnetic rings are the same. This avoids the situation similar to the existing one where due to the unreliable internal circuit design of the motor protector (that is, generally in the prior art, the specific layout of the circuit is not considered, and mostly as long as the circuit can be made to work), when the radio frequency device senses signals through the three magnetic rings, there are differences in the wavelengths input into the motor protector, which further causes interference to the motor protector and results in random jumping of alarm signals such as overload, open phase, locked rotor, or underload.

[0012] At the same time, through the improvement of the control circuit on the PCB board, that is, on the three wiring circuits connected to the three magnetic rings, the number of resistors in parallel with the wiring terminal is increased from one in the traditional way to two. In this way, during each wiring process, the resistors can be respectively connected to the positive and negative input positions corresponding to the input of the single-phase metering chip. Thus, through the action of the resistors on the control circuit of the PCB board, a standard differential signal can be formed on the control circuit, avoiding the situation similar to the existing one where due to only one resistor, when the signal is output, asymmetry occurs, and then the differential signal on the control circuit is not standard. Although the existing one can also be used on the motor protector, its interference resistance is poor. Description of the Drawings

[0013] Figure 1It is a three-dimensional schematic diagram of the motor protector in the specific embodiment of the present utility model;

[0014] Figure 2 It is a schematic structural diagram of the PCB board in the specific embodiment of the present utility model;

[0015] Figure 3 It is Figure 2 an enlarged schematic diagram of;

[0016] Figure 4 It is a circuit schematic diagram of the current sampling circuit in the specific embodiment of the present utility model;

[0017] Figure 5 It is a circuit schematic diagram of the single-phase metering chip U1 in the specific embodiment of the present utility model. Specific implementation manner

[0018] As Figures 1-3 shown, the specific embodiment of the present utility model is an anti-interference motor protector, which includes a housing 1, three magnetic rings 2 arranged in the housing 1 for the external A, B, and C three-phase live wires to pass through respectively, and a PCB board 3 arranged in the housing 1. Each of the three magnetic rings 2 includes pins, and through the three pins, the three magnetic rings 2 are respectively welded to the PCB board 3. The PCB board 3 includes three wiring lines corresponding to and communicating with the three magnetic rings 2, and the wiring lengths of the three wiring lines are the same. Through the three wiring lines with the same wiring length, the inside of the PCB board 3 can be connected to the three magnetic rings 2 through standard differential signals, and the standard differential signal output of the PCB board 3 is stable.

[0019] As Figures 2-3 shown, the three wiring lines include two outer lines 311 distributed on both sides and an intermediate line 312 distributed between the two outer lines 311. The two outer lines 311 are in a diagonal structure, and the intermediate line 312 is in a curved distribution.

[0020] As Figures 2-5 shown, the PCB board 3 includes a control circuit. The control circuit includes a current sampling circuit and a single-phase metering chip U1. The single-phase metering chip U1 includes pins V1P, V1N, V2P, V2N, V3P, and V3N for inputting the collected current into the chip. The current sampling circuit includes an A-phase current sampling circuit, a B-phase current sampling circuit, and a C-phase current sampling circuit;

[0021] The A-phase current sampling circuit includes a terminal block CN1, resistors R1, R2, R5, R6, capacitors C1, C7. The pin 2 of the terminal block CN1 is respectively connected to one end of the resistor R1 and one end of the resistor R2. The other end of the resistor R1 is respectively connected to one end of the capacitor C1 and the pin V3N of the single-phase metering chip U1. The pin 1 of the terminal block CN1 is respectively connected to one end of the resistor R5 and one end of the resistor R6. The other end of the resistor R6 is respectively connected to one end of the capacitor C7 and the pin V3P of the single-phase metering chip U1. The other end of the resistor R2 and the other end of the resistor R5 are commonly connected to the ground terminal. The other end of the capacitor C1 and the other end of the capacitor C7 are commonly connected to the ground terminal. And the wiring length from the resistor R2 to the pin V3N of the single-phase metering chip U1 in the A-phase current sampling circuit is equal to the wiring length from the resistor R5 to the pin V3P of the single-phase metering chip U1;

[0022] The B-phase current sampling circuit includes a terminal block CN2, resistors R7, R8, R11, R13, capacitors C16, C17. The pin 2 of the terminal block CN2 is respectively connected to one end of the resistor R7 and one end of the resistor R8. The other end of the resistor R7 is respectively connected to one end of the capacitor C16 and the pin V1N of the single-phase metering chip U1. The pin 1 of the terminal block CN2 is respectively connected to one end of the resistor R11 and one end of the resistor R13. The other end of the resistor R13 is respectively connected to one end of the capacitor C13 and the pin V1P of the single-phase metering chip U1. The other end of the resistor R8 and the other end of the resistor R11 are commonly connected to the ground terminal. The other end of the capacitor C16 and the other end of the capacitor C17 are commonly connected to the ground terminal. And the wiring length from the resistor R8 to the pin V1N of the single-phase metering chip U1 in the B-phase current sampling circuit is equal to the wiring length from the resistor R11 to the pin V1P of the single-phase metering chip U1;

[0023] The C-phase current sampling circuit includes a terminal block CN3, resistors R14 - R17, capacitors C18, C23. The pin 2 of the terminal block CN3 is respectively connected to one end of the resistor R14 and one end of the resistor R15. The other end of the resistor R14 is respectively connected to one end of the capacitor C18 and the pin V2N of the single-phase metering chip U1. The pin 1 of the terminal block CN2 is respectively connected to one end of the resistor R16 and one end of the resistor R17. The other end of the resistor R17 is respectively connected to one end of the capacitor C23 and the pin V2P of the single-phase metering chip U1. The other end of the resistor R15 and the other end of the resistor R16 are commonly connected to the ground terminal. The other end of the capacitor C18 and the other end of the capacitor C23 are commonly connected to the ground terminal. And the wiring length from the resistor R15 to the pin V2N of the single-phase metering chip U1 in the C-phase current sampling circuit is equal to the wiring length from the resistor R15 to the pin V2P of the single-phase metering chip U1.

[0024] When wiring the three magnetic rings 2 through which the corresponding A, B, and C phase live wires on the internal PCB board 3 of the motor protector, the three wiring lines for respectively connecting the three magnetic rings 2 to the inside of the PCB are involved. At the same time, the lengths of these three wiring lines are the same. Thus, when the motor protector works, the inside of the PCB board 3 can ensure, through the action of standard differential signals, that the wavelengths induced by the three magnetic rings 2 of the motor protector are the same when a radio frequency device approaches. This avoids the situation similar to the existing one where, due to the unreliable internal circuit design of the motor protector (i.e., in the existing design, the specific layout of the circuit is generally not considered, and mostly as long as the circuit can be made to work), when the radio frequency device senses signals through the three magnetic rings 2, there are differences in the wavelengths input into the motor protector, resulting in interference to the motor protector and the chaotic jumping of alarm signals such as overload, open phase, locked rotor, or underload.

[0025] At the same time, through the improvement of the control circuit on the PCB board 3, that is, on the three wiring lines connected to the three magnetic rings 2, the number of resistors in parallel with the terminal block is increased from one in the traditional design to two. In this way, during each wiring process, the resistors can be respectively connected to the positive and negative input positions corresponding to the single-phase metering chip. Thus, the control circuit on the PCB board 3 can also form standard differential signals through the action of the resistors, avoiding the situation similar to the existing one where, due to only one resistor, asymmetry occurs during signal output, resulting in non-standard differential signals on the control circuit. Although the existing design can also be used in the motor protector, its interference resistance is poor.

Claims

1. An anti-interference motor protector, comprising a housing, three magnetic rings arranged in the housing for the external A, B, and C three-phase live wires to pass through respectively, and a PCB board arranged in the housing. Each of the three magnetic rings includes pins, and the three magnetic rings are respectively formed with the three pins and welded to the PCB board. It is characterized in that: The PCB board includes three wiring lines respectively and correspondingly connected to three magnetic rings, and the wiring lengths of the three wiring lines are the same. Through the three wiring lines with the same wiring length, the internal part of the PCB board can be connected to the three magnetic rings through standard differential signals, and the standard differential signal output of the PCB board is stable.

2. The anti-interference motor protector according to claim 1, wherein: The three wiring lines include two outer lines distributed on both sides and an intermediate line distributed between the two outer lines. The two outer lines are in an inclined line structure, and the intermediate line is in a curved distribution.

3. The anti-interference motor protector according to claim 1 or 2, characterized in that: The PCB board includes a control circuit, and the control circuit includes a current sampling circuit and a single-phase metering chip U1. The single-phase metering chip U1 includes pins V1P, V1N, V2P, V2N, V3P, and V3N for inputting the collected current into the chip. The current sampling circuit includes a phase A current sampling circuit, a phase B current sampling circuit, and a phase C current sampling circuit; The phase A current sampling circuit includes a terminal block CN1, resistors R1, R2, R5, R6, capacitors C1, C7. The pin 2 of the terminal block CN1 is respectively connected to one end of the resistor R1 and one end of the resistor R2. The other end of the resistor R1 is respectively connected to one end of the capacitor C1 and the pin V3N of the single-phase metering chip U1. The pin 1 of the terminal block CN1 is respectively connected to one end of the resistor R5 and one end of the resistor R6. The other end of the resistor R6 is respectively connected to one end of the capacitor C7 and the pin V3P of the single-phase metering chip U1. The other end of the resistor R2 and the other end of the resistor R5 are commonly grounded. The other end of the capacitor C1 and the other end of the capacitor C7 are commonly grounded. And the wiring length from the resistor R2 to the pin V3N of the single-phase metering chip U1 in the phase A current sampling circuit is equal to the wiring length from the resistor R5 to the pin V3P of the single-phase metering chip U1; The phase B current sampling circuit includes a terminal block CN2, resistors R7, R8, R11, R13, capacitors C16, C17. The pin 2 of the terminal block CN2 is respectively connected to one end of the resistor R7 and one end of the resistor R8. The other end of the resistor R7 is respectively connected to one end of the capacitor C16 and the pin V1N of the single-phase metering chip U1. The pin 1 of the terminal block CN2 is respectively connected to one end of the resistor R11 and one end of the resistor R13. The other end of the resistor R13 is respectively connected to one end of the capacitor C13 and the pin V1P of the single-phase metering chip U1. The other end of the resistor R8 and the other end of the resistor R11 are commonly grounded. The other end of the capacitor C16 and the other end of the capacitor C17 are commonly grounded. And the wiring length from the resistor R8 to the pin V1N of the single-phase metering chip U1 in the phase B current sampling circuit is equal to the wiring length from the resistor R11 to the pin V1P of the single-phase metering chip U1; The described C-phase current sampling circuit includes a wiring terminal CN3, resistors R14 - R17, and capacitors C18, C23. The pin 2 of the wiring terminal CN3 is respectively connected to one end of the resistor R14 and one end of the resistor R15. The other end of the resistor R14 is respectively connected to one end of the capacitor C18 and the pin V2N of the single-phase metering chip U1. The pin 1 of the wiring terminal CN2 is respectively connected to one end of the resistor R16 and one end of the resistor R17. The other end of the resistor R17 is respectively connected to one end of the capacitor C23 and the pin V2P of the single-phase metering chip U1. The other end of the resistor R15 and the other end of the resistor R16 are commonly grounded. The other end of the capacitor C18 and the other end of the capacitor C23 are commonly grounded. And in the C-phase current sampling circuit, the wiring length from the resistor R15 to the pin V2N of the single-phase metering chip U1 is equal to the wiring length from the resistor R15 to the pin V2P of the single-phase metering chip U1.

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