Motor over-temperature and over-current alarm protection circuit

Abstract

The utility model provides a motor over-temperature and over-current alarm protection circuit which has over-temperature and over-current protection functions and an alarm function and can cut off power supply of a motor and protect the motor from being damaged when the motor is over-temperature or over-current. An alarm function can be provided when the motor is over-temperature or over-current; the current temperature interval of the motor shell can be prompted when the motor runs. The circuit comprises an over-temperature protection circuit, a non-contact over-current protection circuit, a motor alarm circuit and an alarm signal latch circuit. The over-temperature protection circuit and the non-contact over-current protection circuit are connected with the motor alarm circuit; the output of the over-temperature protection circuit and the non-contact over-current protection circuit controls the on-off of the motor alarm circuit so as to protect the motor and give an alarm; wherein the non-contact over-current protection circuit can measure the current of the motor without directly connecting an output line of the motor to the circuit by utilizing a Hall effect when collecting the current of the motor; the over-temperature protection circuit controls an LED lamp in the over-temperature protection circuit to be turned on or off so as to prompt the current motor shell temperature interval. An LED lamp in the alarm signal latch circuit is turned on or off to prompt that the circuit gives an alarm.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of protection circuit, specifically provide a motor overtemperature and overcurrent alarm protection circuit. BACKGROUND

[0002] At present, in some high temperature operation scene, motor needs to keep high load work, this easily leads to overcurrent fault, and the severe operation environment aggravates the heating degree of motor, and the motor is easily faced with the risk of serious overtemperature damage. Therefore, when the motor overtemperature or overcurrent fault occurs, the protection of motor is particularly important. The motor overtemperature and overcurrent protection circuit can identify whether the motor is in overheat or overcurrent state, and take measures to make the motor stop running in time, effectively prevent the motor from being damaged and even burned, which is very important for the safe operation of the motor in high temperature complex environment.

[0003] The existing motor overtemperature and overcurrent protection circuit is mostly connected to the inside of the motor to collect current, which increases the external interference of the motor, and also brings the inconvenience of measuring current. In view of the phenomenon that the motor is easily disturbed during operation, leading to the decline of operation stability, and in order to simplify the way of measuring motor current, therefore, it is very important to design a protection circuit which can ensure the safe operation of motor, does not interfere with its normal work, and is easy to measure motor current. Under this background, the motor overtemperature and overcurrent alarm protection circuit is proposed, which can measure the current of the motor without directly contacting the inside of the motor, greatly simplifying the way of measuring motor current, and reducing the external interference of the motor during operation. At the same time, when the motor overtemperature or overcurrent, the circuit disconnects the motor power supply, ensures the safe operation of the motor, in addition, the overtemperature protection circuit also provides the light and off of LED when the motor runs in different temperature intervals, which is convenient for prompting the current motor running temperature interval of staff, and the alarm signal latch circuit is designed in the circuit, which latches the overtemperature alarm information after the overtemperature alarm occurs, so that the staff can know whether the overtemperature or overcurrent alarm occurs in the subsequent motor. It is suitable for the safe operation protection of various motors in the environment which is complex and inconvenient for personnel to pay attention to at all times. SUMMARY

[0004] The utility model discloses to the above -mentioned problem provides a kind of motor over-temperature and over-current alarm protection circuit, and the circuit includes: over-temperature protection circuit, non-contact over-current protection circuit, motor alarm circuit, alarm signal latch circuit. By thermistor close motor shell surface, measure motor shell temperature, by the light-off of different LED lamp inside circuit, the current motor temperature interval, when motor operating temperature exceeds over-temperature protection circuit temperature protection threshold, over-temperature protection circuit control motor alarm circuit relay disconnect, make motor stop running, while LED lamp in motor alarm circuit flashes, buzzer emits sound, to reach protection and alarm effect;Motor output line passes annular Hall device WCS1500, annular Hall device WCS1500 passes through Hall induction principle, without accessing motor interior can measure the current of motor output line, when motor output line flows non-contact over-current protection circuit current protection threshold, non-contact over-current protection circuit control motor alarm circuit relay disconnect, make motor stop running, while LED lamp in motor alarm circuit flashes, buzzer emits sound, to reach protection and alarm effect;After over-temperature protection circuit alarm generation, alarm signal latch circuit LED lamp is always bright, prompt over-temperature alarm occurs, need manually press alarm signal latch circuit switch to make alarm signal latch circuit LED lamp extinguish, play alarm signal latch and signal clearing function.

[0005] In order to achieve the above object, the utility model provides the following technical scheme:

[0006] A kind of motor over-temperature and over-current alarm protection circuit includes:

[0007] Over-temperature protection circuit, temperature measuring thermistor RT1 is connected to input end, thermistor RT1 is close to motor shell surface, thermistor RT1 measures motor shell temperature variation, converts into corresponding electrical signal variation as the input signal of over-temperature protection circuit, over-temperature protection circuit output end is connected with the upper port of relay RL1 control end in the described motor alarm circuit and the input end of alarm signal latch circuit, ensure that the on-off of control motor alarm circuit when motor over-temperature, control the operation and issue alarm of motor, while control the light-off of alarm signal latch circuit LED lamp L5;

[0008] Non-contact over-current protection circuit, annular Hall device WCS1500 is connected to input end to measure current, annular Hall device WCS1500 measures the current of motor output line by Hall induction, without accessing motor interior, upper port of relay RL1 control end in the described motor alarm circuit is connected to output end, ensure that the on-off of control motor alarm circuit when motor over-current, control the operation and issue alarm of motor;

[0009] The motor alarm circuit is connected with the output end of the over-temperature protection circuit and the output end of the non-contact over-current protection circuit at the input end, and is connected with the motor and the buzzer BUZ1 and the LED lamp L4 at the output end. The motor is connected with the buzzer BUZ1 and the LED lamp L4 through different output ends of the relay. When the circuit alarms, the motor can be controlled to be disconnected, the buzzer BUZ1 can be controlled to emit sound, and the LED lamp L4 can be controlled to flash, so that the motor protection and alarm functions are achieved.

[0010] The alarm signal latching circuit is connected with the output end of the over-temperature protection circuit at the input end. When the high-level output of the over-temperature protection circuit is received, the LED lamp L5 is kept flashing. When the high-level output changes to low level, the LED lamp L5 can be kept flashing, so that the alarm is prompted to be over-temperature alarm. The LED lamp L5 can be turned off only by manually pressing the switch S1, so that the alarm signal latching and alarm signal clearing functions are achieved.

[0011] The over-temperature protection circuit (20) comprises: a direct current power supply VCC, a diode D1, amplifiers U1 and U2, an NPN type transistor Q1, a PNP type transistor Q2, LED lamps L1, L2 and L3, a 555 timer U5, a thermistor RT1, resistors R1, R2, R3, R4, R5, R6 and R7, and a capacitor C1. In the over-temperature protection circuit (20), one end of the resistor R1 is connected to the power supply, and the other end is connected to the thermistor RT1 and the non-inverting terminal of the amplifier U2; one end of the resistor R2 is connected to the power supply, and the other end is connected to the resistors R3 and the inverting terminal of the amplifier U2; one end of the thermistor RT1 is connected to the resistor R1 and the inverting terminal of the amplifier U2, and the other end is connected to the ground; the inverting terminal of the amplifier U2 is connected to the resistor R2 and the resistor R3, and the resistors R2, R3 and R4 form a voltage acquisition circuit; the non-inverting terminal of the amplifier U2 is connected to the resistor R1 and the thermistor RT1, and the thermistor RT1 and the resistor R1 form a voltage acquisition circuit; the output terminal of the amplifier U2 is connected to the diode D1, the resistor R6 and the emitter of the NPN type transistor, the diode D1 is connected to one end of the LED lamp L2, the other end of the LED lamp L2 is connected to the power supply, and the other end of the resistor R6 is connected to the LED lamp L3; the LED lamp L3 is controlled to be bright or dark by the signal output by the amplifier U2, the diode D1 is controlled to be conductive, and thus the LED lamp L2 is controlled to be bright or dark; the inverting terminal of the amplifier U1 is connected to the resistor R1 and the thermistor RT1, and the non-inverting terminal of the amplifier U1 is connected to the resistors R3 and R4; the output terminal of the amplifier U1 is connected to the resistor R5 and the input terminal of the 555 timer U5, one end of the resistor R5 is connected to the base of the NPN type transistor Q1 and one end of the LED lamp L1, and the LED lamp L1 is controlled to be bright or dark by the signal output by the amplifier U1, and the NPN type transistor Q1 is controlled to be conductive or not, so as to control the LED lamp L2 to be bright or dark; the output of the amplifier U1 is connected to the input of the timer U5, the output of the timer U5 is connected to the base of the PNP type transistor Q2, the resistor R7 and the inverting input terminal of the amplifier U4 in the alarm signal latch circuit (50) and the LED lamp L6, the collector of the PNP type transistor Q2 is connected to the control terminal of the relay RL1 in the motor alarm circuit (40), the PNP type transistor Q2 is controlled to be conductive by the signal output by the timer U5, and thus the signal T-OUT controls the motor alarm circuit (40).

[0012] Further, the over-temperature protection circuit (20) amplifies the voltage output of the same-phase input and the opposite-phase input to control the brightness of the LED lamps L2 and L3; the amplifier U1 amplifies the voltage output of the same-phase input and the opposite-phase input to control the brightness of the LED lamp L1 and the on-off of the NPN transistor Q1, the on-off of the NPN transistor Q1 controls the brightness of the LED lamp L2; the output end of the amplifier U1 is connected to the input end of the timer U5, the output signal of the amplifier U1 controls the output signal of the timer U5, the output end of the timer U5 is connected to the opposite-phase input end of the amplifier U4 in the alarm signal latching circuit (50) and the LED lamp L6, the output control signal V-OUT of the output end of the timer U5 controls the brightness of the LED lamp L6 and the output of the amplifier U4 in the alarm signal latching circuit (50).

[0013] The non-contact over-current protection circuit (30) comprises a direct-current power supply VCC, slide resistors RV1 and RV2, a ring-shaped Hall component U6, an NPN transistor Q3 and an amplifier U3; the slide resistor RV1 and the direct-current power supply VCC are connected to simulate the motor current, the resistance of the slide resistor RV1 is adjusted to generate different current values, the input end of the ring-shaped Hall component U6 is connected to the slide resistor RV1, the current of the motor output line passes through the ring-shaped Hall component U6, the current generated by the slide resistor RV1, i.e. the current of the motor output line, is directly converted into an output voltage by the Hall effect, so that the motor current can be measured without connecting the motor output line into the motor over-temperature and over-current alarm protection circuit, and the ring-shaped Hall component U6 is connected to the same-phase end of the amplifier U3; the opposite-phase end of the amplifier U3 is connected to the slide resistor RV3, and the output end of the amplifier U3 is connected to the base of the NPN transistor Q3; the emitter of the NPN transistor Q3 is connected to the motor alarm circuit (40), and the collector of the NPN transistor Q3 is connected to the direct-current power supply VCC; the ring-shaped Hall component U6 converts the input current into an output voltage and is connected to the same-phase end of the amplifier U3, the amplifier U3 compares the voltage of the same-phase input and the opposite-phase input and outputs a high or low level, the output signal of the amplifier U3 controls the conduction of the NPN transistor Q3, the NPN transistor Q3 outputs a control signal E-OUT, thereby controlling the motor alarm circuit (40).

[0014] The motor alarm circuit (40) comprises: a direct current motor power supply VC, a relay RL1, a buzzer BUZ1, a direct current motor M, an LED lamp L4, and a resistor R8; the direct current motor power supply is connected to the normally closed input end of the relay RL1, the normally closed output end of the relay RL1 is connected to the motor M, the motor M is connected to the resistor R8 and grounded; the other output end of the relay RL1 is connected to the buzzer BUZ1, the buzzer BUZ1 is connected to the LED lamp L4, and the LED lamp L4 is finally connected to the resistor R8 and grounded; the upper port KT of the relay control end is connected to the collector of the PNP type triode Q2 in the over-temperature protection circuit (20) and the emitter of the NPN type triode Q3 in the non-contact over-current protection circuit (30); when the relay RL1 receives a signal from the triode Q1 or Q2, the relay RL1 switch operates, thereby controlling the operation and stop of the motor M, controlling the on-off of the buzzer BUZ1 and the LED lamp L4, and achieving the protection and alarm effects.

[0015] The alarm signal latch circuit (50) comprises: a direct current power supply VCC, an amplifier U4, a relay RL2, a diode D2, LED lamps L5 and L6, NPN type triodes Q4 and Q6, a PNP type triode Q5, a switch S1, resistors R9, R10, R11, R12, R13, R14, R15 and R16; the relay RL2 is connected to the power supply at a normally open input end, and the upper port KT of the control end is connected to the emitter of the NPN type triode Q4; one end of the normally open output end of the relay RL2 is connected to one end of the resistors R13, R14 and R15, the resistor R14 is connected to the base of the NPN type triode Q6, one end of the resistor R15 is connected to the ground, one end of the resistor R13 is connected to the collector of the PNP type triode Q5 and one end of the resistor R12, the emitter of the NPN type triode Q6 is connected to the resistor R16 connected to the ground, the collector of the NPN type triode Q6 is connected to the switch S1, the resistor R11 and the base of the PNP type triode Q5, the emitter of the PNP type triode Q5 is connected to the direct current power supply VCC and the resistor R11, the collector of the PNP type triode Q5 is connected to the resistors R12 and R13, the other end of the switch S1 is connected to the direct current power supply VCC, and the resistor R12 is connected to the LED lamp L5 connected to the ground; the non-inverting terminal of the amplifier U4 is connected to the resistors R9 and R10, the resistor R9 is connected to the ground, and the resistor R10 is connected to the direct current power supply VCC and the collector of the NPN type triode Q4; the resistors R9 and R10 form a voltage measurement circuit, and the non-inverting terminal of the amplifier U4 measures the voltage of the resistor R9; the inverting terminal of the amplifier U4 is connected to the LED lamp L6 and the output end of the over-temperature protection circuit; when the control signal V-OUT output by the timer U5 in the over-temperature protection circuit (20) is input to the inverting output end of the amplifier U4, the amplifier U4 outputs a high level signal to the base of the NPN type triode Q4, the NPN type triode Q4 is turned on, the relay RL2 is switched, the relay power supply is connected to the alarm signal latch circuit (50), the voltage on the resistor R14 connected to the base of the NPN type triode Q6 is obtained, the NPN type triode Q6 is turned on, the collector of the NPN type triode Q6 is connected to the base of the PNP type triode Q5, and thus the PNP type triode Q5 is turned on, the LED lamp L5 is brightened, after the PNP type triode Q5 is turned on, the collector thereof is connected to the base of the NPN type triode Q6 through the resistor R13, the NPN type triode Q6 is continuously turned on, the NPN type triode Q6 is turned on, the PNP type triode Q5 is continuously turned on, the LED lamp L5 is continuously brightened, and the motor is prompted to have an over-temperature alarm; only when the switch S1 is pressed, the LED lamp L5 is extinguished, and the over-temperature alarm signal latch and the over-temperature alarm signal clearing functions are achieved.

[0016] The effective gain effect brought by the utility model is as follows:

[0017] The utility model discloses a motor alarm protection circuit, with overtemperature, overcurrent protection function and alarm function, can cut off motor power supply when overtemperature or overcurrent fault occurs, protect motor from being damaged, can make the alarm of the sound of buzzer and the bright of LED lamp when overtemperature and overcurrent fault occur, the utility model discloses a circuit is provided to the overcurrent protection motor current measurement of motor, need not direct contact motor interior to measure its current, greatly facilitate the measurement of motor current, reduce external interference when motor operation simultaneously, overtemperature protection circuit provides the bright of LED to prompt the temperature interval of motor operation, and the utility model discloses overtemperature alarm latching function, after overtemperature alarm occurs, alarm signal latching circuit LED lamp keeps constant brightness, so that staff consults overtemperature alarm information, only manual closing switch can make alarm signal latching circuit clear alarm signal, restores the original state.

[0018] Compared with traditional motor overtemperature or overcurrent protection measures, the protection measures provided by the utility model are aimed at overtemperature and overcurrent protection simultaneously, and the motor current collected by the overcurrent protection circuit utilizes Hall effect to measure the current by the method of non-direct contact with the motor interior, facilitating motor current measurement, the overtemperature protection circuit also provides the bright of LED under the operation of different temperature intervals of motor, facilitating the acquisition of current motor operation temperature interval, the utility model discloses alarm signal latching circuit, aimed at overtemperature alarm, latches alarm information, so that staff understands the alarm situation. It is suitable for the safe operation protection of various motors in the environment that is complex and inconvenient for personnel to pay attention to at all times. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is the motor overtemperature and overcurrent alarm protection circuit working flow chart provided by the utility model.

[0020] Figure 2 It is the overtemperature protection circuit principle diagram of the motor overtemperature and overcurrent alarm protection circuit provided by the utility model.

[0021] Figure 3 It is the non-contact overcurrent protection circuit principle diagram of the motor overtemperature and overcurrent alarm protection circuit provided by the utility model.

[0022] Figure 4 It is the motor alarm circuit principle diagram of the motor overtemperature and overcurrent alarm protection circuit provided by the utility model.

[0023] Figure 5 It is the alarm signal latching circuit principle diagram of the motor overtemperature and overcurrent alarm protection circuit provided by the utility model.

[0024] Figure 6 It is the overall principle diagram of a motor over-temperature and over-current alarm protection circuit. Specific embodiments

[0025] In order to clearly describe the technical scheme, advantages and working principle of the utility model, the utility model will be more complete and clear in the following with the help of the drawings.

[0026] As Figure 1 shown, a motor over-temperature and over-current alarm protection circuit comprises:

[0027] The over-temperature protection circuit has a temperature measuring thermistor connected to the input end, and the output end is connected to the upper port of the relay control end in the motor alarm circuit and the input end of the alarm signal latch circuit; the thermistor is close to the surface of the motor shell, measures the shell temperature when the motor is running, and prompts the current shell temperature interval of the motor through different LED lights in the circuit; when the motor shell temperature exceeds the threshold value allowed for the motor operation, the over-temperature protection circuit sends a control signal to control the motor on-off of the motor alarm circuit, the on-off of the alarm LED light and the continuous sound of the buzzer, thereby controlling the operation of the motor and sending an alarm, and at the same time, the control signal sent by the over-temperature protection circuit controls the LED light of the alarm signal latch circuit to be always on, thereby indicating that the over-temperature alarm has occurred;

[0028] The non-contact over-current protection circuit has a ring-shaped Hall element WCS1500 connected to the input end, which is used to measure the current of the motor output line; the ring-shaped Hall element WCS1500 converts the current of the motor output line passing through it into voltage through the Hall effect, measures the size of the motor current, and measures the current of the motor output line without accessing the motor interior, thereby reducing the external interference during the operation of the motor and simplifying the process of measuring the motor current; the output end is connected to the upper port of the relay control end in the motor alarm circuit; when the current flowing through the motor exceeds the threshold value allowed for normal operation, the non-contact over-current protection circuit sends a control signal to control the on-off of the motor alarm circuit, the on-off of the alarm LED light and the continuous sound of the buzzer, thereby controlling the operation of the motor and sending an alarm;

[0029] The motor alarm circuit has an input end connected to the output end of the over-temperature protection circuit and the output end of the non-contact over-current protection circuit, and an output end connected to the motor, the buzzer and the LED light; whether it is over-temperature alarm or over-current alarm, the relay in the motor alarm circuit can be disconnected in time, thereby disconnecting the motor operation; the relay is connected to the buzzer in the motor alarm circuit, continuously sends sound and the LED light flashes, and achieves the motor protection and alarm effect;

[0030] The alarm signal latching circuit is connected with the output end of the over-temperature protection circuit, and is used for keeping the LED lamp in the alarm signal latching circuit shining when receiving the high level output of the over-temperature protection circuit, and keeping the LED lamp shining when receiving any signal of the output end of the over-temperature protection circuit thereafter, so as to prompt that the over-temperature alarm has occurred, and the LED lamp can be turned off only by manually pressing the switch, thereby realizing the functions of latching and clearing the alarm signal.

[0031] As shown in Figure 2 The over-temperature protection circuit (20) comprises: a direct current power supply VCC, a thermistor RT1, resistors R1, R2, R3 and R4, a voltage measurement and comparison module (201) composed of amplifiers U1 and U2, a temperature prompting circuit module (202) composed of resistors R5 and R6, LED lamps L1, L2 and L3, a diode D1 and an NPN type transistor Q1, an over-temperature alarm signal output module (203) composed of a PNP type transistor Q2, a 555 timer U5, a resistor R7 and a capacitor C1.

[0032] Further, in the voltage measurement and comparison module (201), the thermistor RT1 is close to the motor shell, the resistance of the thermistor RT1 decreases with the increase of the temperature of the motor shell, the change of the temperature of the motor is converted into the change of the electric signal, the upper end of the resistor R1 is connected with the direct current power supply VCC, and the lower end is connected with the thermistor RT1; the upper end of the resistor R2 is connected with the direct current power supply VCC, and the lower end is connected with the resistor R3 and the reverse end of the amplifier U2; the upper end of the thermistor RT1 is connected with the same phase end of the amplifier U2, and the lower end is grounded; the same phase end of the amplifier U2 is connected with the upper end of the thermistor RT1 and the lower end of the resistor R1; the thermistor RT1 and the resistor R1 constitute a voltage acquisition circuit, and the voltage on the same phase end of the amplifier U2 is the voltage on the thermistor RT1; the reverse end of the amplifier U2 is connected with the lower end of the resistor R2 and the upper end of the resistor R3; the lower end of the resistor R3 is connected with the upper end of the resistor R4, and the lower end of the resistor R4 is grounded; the resistors R2, R3 and R4 constitute a voltage acquisition circuit, and the voltage on the reverse end of the amplifier U2 is the sum of the voltages on the resistors R3 and R4; the upper end of the resistor R4 is connected with the same phase end of the amplifier U1, the resistors R2, R3 and R4 constitute a voltage acquisition circuit, and the voltage on the same phase end of the amplifier U1 is the voltage on the resistor R4; the reverse end of the amplifier U1 is connected with the lower end of the resistor R1, the upper end of the thermistor RT1 and the same phase end of the amplifier U2; the reverse end of the amplifier U1 is the voltage on the thermistor RT1; and the amplifiers U1 and U2 output high and low levels by comparing the voltages on the same phase end and the reverse end.

[0033] Further, in the temperature prompting circuit module (202), the output end of the amplifier U2 is connected to the lower end of the diode D1, the upper end of the resistor R6 and the emitter of the NPN transistor Q1, the upper end of the LED lamp L2 is connected to the lower end of the diode D1, the upper end of the LED lamp L2 is connected to the power supply and the collector of the NPN transistor, the lower end of the LED lamp L3 is connected to the upper end of the resistor R6, and the ground is connected to the lower end of the LED lamp L3. The on-off of the LED lamp L3 is controlled by the signal output by the amplifier U2. The output end of the amplifier U1 is connected to the upper end of the resistor R5, the lower end of the resistor R5 is connected to the base of the NPN transistor Q1 and the upper end of the LED lamp L1, and the ground is connected to the lower end of the LED lamp L1. The on-off of the LED lamp L1 and the conduction of the NPN transistor Q1 are controlled by the output end of the amplifier U1.

[0034] Further, the working principle of the temperature prompting circuit module (202) is as follows: when the temperature of the thermistor RT1 is low, the in-phase voltage of the amplifier U1 is less than the reverse voltage, the output of the amplifier U1 is low, the in-phase voltage of the amplifier U2 is greater than the reverse voltage, the output of the amplifier U2 is high, and the LED lamp L3 is on. At this time, the LED lamps L1 and L2 remain off. When the temperature of the thermistor RT1 is higher than 85 degrees Celsius, the in-phase voltage of the amplifier U2 is less than the reverse voltage, the output of the amplifier U2 is low, the diode D1 is turned on, the LED lamp L2 is on, the in-phase voltage of the amplifier U1 is less than the reverse voltage, the output of the amplifier U1 is low, and the LED lamp L1 remains off. At this time, the LED lamp L3 is off because the voltage of the LED lamp L3 is insufficient to light up due to the voltage drop of the diode D1. When the temperature of the thermistor RT1 is higher than 121 degrees Celsius, the in-phase voltage of the amplifier U1 is greater than the reverse voltage, the output of the amplifier U1 is high, the LED lamp L1 is on, the NPN transistor Q1 is turned on, the LED lamp L2 is off, the in-phase voltage of the amplifier U1 is less than the reverse voltage, the output of the amplifier U1 is low, and the LED lamp L3 remains off. Thus, the on-off of the LED lamps L1, L2 and L3 prompts the temperature range of the motor shell. When the temperature of the motor shell measured by the thermistor is lower than 85 degrees Celsius, the LED lamp L3 is on. When the measured temperature is higher than 85 degrees Celsius, the LED lamp L2 is on. When the temperature is higher than 121 degrees Celsius, the LED lamp L1 is on. The circuit can change the voltage of the in-phase input end of the amplifier U1 and the voltage of the reverse end of the amplifier U2 by replacing the values of the resistors R3 and R4 to adjust the temperature threshold of the thermistor when the LED lamps L1, L2 and L3 are on.

[0035] Further, in the over-temperature alarm signal output module (203), the output end of the amplifier U1 is connected with the input end TR and TH of the 555 timer U5, the output end Q of the 555 timer U5 is connected with the base of the PNP triode Q2, the upper end of the resistor R7, the inverting input end of the amplifier U4 in the alarm signal latch circuit (50) and the lower end of the LED lamp L6, the lower end of the resistor R7 is grounded, the CV port of the 555 timer U5 is connected with the upper end of the capacitor C1, the lower end of the capacitor C1 is grounded, the collector of the PNP triode Q2 is connected with the collector of the NPN triode Q3 in the non-contact over-current protection circuit (30) and the upper end of the control end of the relay RL1 in the motor alarm circuit (40), and the emitter of the PNP triode Q2 is connected with the DC power supply VCC.

[0036] Further, the working principle of the over-temperature alarm signal output module (203) is as follows: when the input end TR and TH of the 555 timer U5 receives the output signal from the amplifier U1, the output end Q of the 555 timer U5 is low when the output signal of the amplifier U1 is high, and the output end Q of the 555 timer U5 is high when the output signal of the amplifier U1 is low, and the on-off of the PNP triode Q2 is controlled by the output signal of the 555 timer U5; when the output signal of the 555 timer U5 is low, the PNP triode Q2 is turned on, the output signal T-OUT controls the relay RL1 in the motor alarm circuit (40), and when the output signal of the 555 timer U5 is low, the output control signal V-OUT controls the brightness of the LED lamp L6 and the output of the amplifier U4 in the alarm signal latch circuit (50); when the temperature of the thermistor RT1 is high, the resistance value is reduced, at this time, the voltage at the same phase end of the amplifier U1 is greater than the voltage at the reverse end, the amplifier U1 outputs high level, the LED lamp L1 is bright, the 555 timer U5 outputs low level, the PNP triode Q2 is turned on, the collector of the PNP triode Q2 is connected with the control end of the relay RL1 in the motor alarm circuit (40), the output signal T-OUT controls the motor alarm circuit (40), and the relay RL1 is switched to act, the motor is disconnected and alarms.

[0037] As shown in Figure 3 The non-contact over-current protection circuit (30) comprises: a DC power supply VCC, a sliding resistor RV1, a non-contact motor current measurement module (301) composed of a ring-shaped Hall element U6; a DC power supply VCC, an NPN triode Q3, an amplifier U3 and a sliding resistor RV2, a voltage comparison and alarm signal output module (302);

[0038] Further, in the non-contact motor current measurement module (301), the lower port of the slide rheostat RV1 is connected with the DC power supply VCC, the resistance of the slide rheostat RV1 is adjusted to generate the size of the analog motor current, the input end +IP of the ring-shaped Hall component U6 is connected with the upper port and the slide end of the slide rheostat RV1, the current of the analog motor output line flows through the ring-shaped Hall component U6, the output end VOUT of the ring-shaped Hall component U6 is connected with the in-phase end of the amplifier U3, the output end -IP of the ring-shaped Hall component U6 is connected with the port GND and is commonly grounded, and the port VCC of the ring-shaped Hall component is connected with the DC voltage.

[0039] Further, in the voltage comparison and alarm signal output module (302), the reverse end of the amplifier U3 is connected with the slide end of the slide rheostat RV3, the upper port of the slide rheostat RV3 is connected with the DC power supply VCC, the lower port of the slide rheostat RV3 is grounded, and the output end of the amplifier U3 is connected with the base of the NPN triode Q3; the emitter of the NPN triode Q3 is connected with the upper port of the relay RL1 control end in the motor alarm circuit (40) and the collector of the PNP triode Q2, and the collector of the NPN triode Q3 is connected with the DC power supply VCC.

[0040] Further, the non-contact overcurrent protection circuit (30) alarm principle: in the simulation experiment using the sliding rheostat RV1 and DC power supply VCC connection, adjust the sliding rheostat RV1 resistance to produce analog motor current size, ring-shaped Hall device U6 input +IP connection sliding rheostat RV1, through the Hall effect, the current of ring-shaped Hall device U6 input port +IP is converted into voltage through port VOUT output to the amplifier U3 in-phase end, in practice, the current of motor output line through the ring-shaped Hall device U6, ring-shaped Hall device U6 is not directly connected to the motor inside; amplifier U3 compares the voltage of the in-phase input and the anti-phase input, outputs high and low level signals, by adjusting the resistance of the sliding rheostat RV1, the current flowing into the input port +IP of the ring-shaped Hall device U6 is changed, the change of the motor current value is simulated; when the motor overcurrent, the current increases, that is, the current value of the input port +IP of the ring-shaped Hall device U6 becomes larger, the voltage of the output end VOUT increases, the voltage of the in-phase end of the amplifier U3 is greater than the anti-phase end, the amplifier U3 outputs high level signal to control the conduction of the NPN triode Q3, the NPN triode Q3 outputs control signal E-OUT, thereby controlling the relay RL1 control end upper port of the motor alarm circuit (40), so that the relay RL1 switch action, the motor is disconnected alarm. By adjusting the resistance of the sliding rheostat RV2, the voltage of the reverse end of the amplifier U3 is increased, at this time, the in-phase end of the amplifier U3 needs a larger voltage to make the amplifier U3 output high level to make the motor alarm, so the voltage of the output end VOUT of the ring-shaped Hall device U6 needs to be larger, the current of the input end +IP of the ring-shaped Hall device U6 needs to be larger, that is, the current value of the motor needs to be larger, so that the current threshold is larger when overcurrent protection occurs, therefore, the resistance of the sliding rheostat RV2 is adjusted to set different current thresholds for different motor overcurrent protection.

[0041] As Figure 4As shown, the motor alarm circuit (40) comprises: DC motor power supply VC, relay RL1, buzzer BUZ1, DC motor M, LED lamp L4, resistor R8; the utility model simulates the experiment in simulation experiment, and adopts DC motor M to carry out experiment, because the overtemperature and overcurrent protection of the utility model is realized by controlling the relay RL1 connected with motor power to realize the overtemperature and overcurrent alarm protection of motor, therefore, DC motor can also be replaced by various other types of motor to carry out experiment, and overtemperature and overcurrent alarm protection can be normally carried out;DC motor power supply connects the normally closed input end of relay RL1, the positive pole of motor M is connected with the normally closed output end of relay RL1, and the negative pole of motor M is connected with the upper end port of resistor R8 and the lower end port of LED lamp L4;the upper end port of buzzer BUZ1 is connected with the other output end of relay RL1, the lower end port of buzzer BUZ1 is connected with the upper end port of LED lamp L4, the lower end port of LED lamp L4 is connected with the negative pole of motor and the upper end port of resistor R8, and the lower end port of resistor R8 is grounded;the upper end port KT of control end of relay RL1 is connected with the collector of PNP type triode Q2 in the overtemperature protection circuit (20) and the emitter of NPN type triode Q3 in the non-contact overcurrent protection circuit (30), and the lower end port of control end of relay RL1 is grounded.

[0042] Further, the alarm protection principle of the motor alarm circuit (40) is as follows: when the signal from triode Q2 or Q3 makes relay RL1 switch action, thereby controlling the power supply of motor M to be disconnected or turned on to control the operation and stop of motor M, buzzer BUZ1 emits sound and LED lamp L4 is bright or dark, so that the motor is protected and alarm is realized.

[0043] As Figure 5As shown, the alarm signal latch circuit (50) comprises: a DC power supply VCC, an amplifier U4, a relay RL2, a diode D2, LED lamps L5, L6, NPN transistors Q4, Q6, a PNP transistor Q5, a switch S1, resistors R9, R10, R11, R12, R13, R14, R15, R16; wherein the relay RL2 has a normally open input end connected to the power supply, the upper port of the control end of the relay RL2 is connected to the emitter of the NPN transistor Q4, the lower port of the control end of the relay RL2 is connected to the ground, the normally open output end of the relay RL2 is connected to the lower port of the resistor R13, the upper port of the resistor R14 and the upper port of the resistor R15, the lower port of the resistor R14 is connected to the base of the NPN transistor Q6, the lower port of the resistor R15 is connected to the ground, the upper port of the resistor R13 is connected to the collector of the PNP transistor Q5 and the upper port of the resistor R12, the emitter of the NPN transistor Q6 is connected to the upper port of the resistor R16, the lower port of the resistor R16 is connected to the ground, the collector of the NPN transistor Q6 is connected to the lower port of the switch S1, the lower port of the resistor R11 and the base of the PNP transistor Q5, the upper port of the switch S1 is connected to the power supply, the switch S1 is in an open state, the upper port of the resistor R11 is connected to the power supply and the emitter of the PNP transistor Q5, the emitter of the PNP transistor Q5 is connected to the DC power supply VCC and the upper port of the resistor R11, the collector of the PNP transistor Q5 is connected to the upper port of the resistor R12 and the upper port of the resistor R13, the lower port of the resistor R12 is connected to the upper port of the LED lamp L5, the lower port of the LED lamp L5 is connected to the ground, the non-inverting terminal of the amplifier U4 is connected to the upper port of the resistor R9 and the lower port of the resistor R10, the resistor R9 is connected to the ground, the upper port of the resistor R10 is connected to the DC power supply VCC and the collector of the NPN transistor Q4, the resistors R9 and R10 form a voltage measurement circuit, the voltage at the upper port of the resistor R9 is the non-inverting terminal of the amplifier U4, the inverting terminal of the amplifier U4 is connected to the lower port of the LED lamp L6 and the output end of the over-temperature protection circuit, the upper port of the LED lamp L6 is connected to the lower port of the diode D2, and the lower port of the diode D2 is connected to the power supply.

[0044] Further, the alarm signal latch circuit (50) alarm signal latch principle: when the over-temperature protection circuit (20) occurs over-temperature alarm, at this time the timer U5 output control signal V-OUT to the amplifier U4 inverter output end is low, so that the amplifier U4 reverse end voltage is less than the same phase end voltage, the amplifier U4 output high level signal to the base of NPN transistor Q4, make NPN transistor Q4 conduction, power through NPN transistor Q4 to the relay RL2 control end, the relay RL2 switch action, so that the relay RL2 power access alarm signal latch circuit (50), at this time the R14 resistance connected to the base of NPN transistor Q6 get voltage, make NPN transistor Q6 conduction, NPN transistor Q6 collector connected to the base of PNP transistor Q5, thus causing PNP transistor Q5 conduction, power flow through PNP transistor Q5 make LED lamp L5 bright, PNP transistor Q5 conduction, its collector through the resistance R13 connected to R14 and R15, resistance R14 get voltage, further keep NPN transistor Q6 conduction, therefore alarm occurs, no matter how the output signal V-OUT in the over-temperature protection circuit (20) changes, NPN transistor Q6 in the alarm signal latch circuit (50) continues to conduct, NPN transistor Q6 conduction causes PNP transistor Q5 conduction, LED lamp L5 keep bright, achieve alarm signal latch function, only when the press switch S1 can make LED lamp L5 extinguish, eliminate alarm signal latch.

[0045] As Figure 6 shown, an overall schematic diagram of a motor over-temperature and over-current alarm protection circuit, including over-temperature protection circuit (20), non-contact over-current protection circuit (30), motor alarm circuit (40), alarm signal latch circuit (50).

Claims

1. An over-temperature and over-current alarm protection circuit for an electric machine, characterized in that, The application relates to a motor protection circuit, which comprises an over-temperature protection circuit (20), a non-contact over-current protection circuit (30), a motor alarm circuit (40) and an alarm signal latch circuit (50). The input signal of the over-temperature protection circuit (20) is an electric signal generated by a thermistor RT1 with temperature change, the thermistor RT1 measures the temperature change of a motor shell and converts the temperature change into a corresponding electric signal change, the output end of the over-temperature protection circuit (20) is connected with the input end of the motor alarm circuit (40) and the alarm signal latch circuit (50). The input end of the non-contact over-current protection circuit (30) is composed of a ring-shaped Hall element WCS1500, the current of a motor output line passes through the ring-shaped Hall element WCS1500, the current change of the motor output line is converted into a corresponding voltage signal change through the Hall effect of the ring-shaped Hall element WCS1500, and the output end of the non-contact over-current protection circuit (30) is connected with the input end of the motor alarm circuit (40). The input end of the motor alarm circuit (40) is connected with the output end of the over-temperature protection circuit (20) and the non-contact over-current protection circuit (30). The input end of the alarm signal latch circuit (50) is connected with the output end of the over-temperature protection circuit (20).

2. The motor over-temperature and over-current alarm protection circuit according to claim 1, characterized in that, The over-temperature protection circuit (20) comprises a direct-current power supply VCC, a thermistor RT1, resistors R1, R2, R3 and R4, a voltage measurement and comparison module (201) composed of amplifiers U1 and U2, a temperature prompting circuit module (202) composed of resistors R5 and R6, LED lamps L1, L2 and L3, a diode D1 and an NPN triode Q1, a over-temperature alarm signal output module (203) composed of a PNP triode Q2, a 555 timer U5, a resistor R7 and a capacitor C1. In the voltage measurement and comparison module (201), the resistor R1 is connected with the direct-current power supply VCC and the thermistor RT1, the resistor R2 is connected with the power supply VCC and the resistor R3, the resistor R3 is connected with the resistor R4, the resistor R4 is grounded, the same-phase end of the amplifier U2 is connected with the thermistor RT1 and the resistor R1, the reverse end of the amplifier U2 is connected with the resistor R2 and the resistor R3, the same-phase end of the amplifier U1 is connected with the resistor R3 and the resistor R4, the reverse end of the amplifier U1 is connected with R1 and the thermistor RT1, and the output end of the amplifier U1 is connected with the resistor R5. In the temperature prompting circuit module (202), the output end of the amplifier U2 is connected with the resistor R6, the diode D1 and the emitter of the NPN triode Q1, the resistor R6 is connected with the LED lamp L3, the diode D1 is connected with the LED lamp L2, the LED lamp L2 is connected with the direct-current power supply VCC and the collector of the NPN triode Q1, and the resistor R5 is connected with the LED lamp L1 and the base of the NPN triode Q1. In the over-temperature alarm signal output module (203), the output of the amplifier U1 is connected with the 555 timer U5, the 555 timer U5 is connected with the capacitor C1, the output end of the 555 timer U5 is connected with the base of the PNP triode Q2, the resistor R7 and the input end of the alarm signal latch circuit (50).

3. The over-temperature and over-current alarm protection circuit for motor according to claim 1, characterized in that, The non-contact over-current protection circuit (30) comprises: a direct current power supply VCC, a slide rheostat RV1, a ring-shaped Hall device U6, a direct current power supply VCC, an NPN triode Q3, an amplifier U3 and a slide rheostat RV2; the ring-shaped Hall device U6 is connected with the slide rheostat RV1, an analog motor output line passes through the ring-shaped Hall device U6, the ring-shaped Hall device U6 is connected with the non-inverting terminal of the amplifier U3, the inverting terminal of the amplifier U3 is connected with the slide rheostat RV3, the slide rheostat RV3 is connected with the direct current power supply VCC, the output terminal of the amplifier U3 is connected with the base of the NPN triode Q3, and the emitter of the NPN triode Q3 is connected with the input terminal of the motor alarm circuit (40).

4. The over-temperature and over-current alarm protection circuit for motor according to claim 1, characterized in that, The motor alarm circuit (40) comprises: a direct current motor power supply VC, a relay RL1, a buzzer BUZ1, a direct current motor M, an LED lamp L4 and a resistor R8; wherein the direct current motor power supply VC is connected with the normally closed input terminal of the relay RL1, the normally closed output terminal of the relay RL1 is connected with the motor M, and the other output terminal of the relay RL1 is connected with the buzzer BUZ1 and the LED lamp L4; the upper port KT of the relay control terminal is connected with the collector of the PNP triode Q2 in the over-temperature protection circuit (20) and the emitter of the NPN triode Q3 in the non-contact over-current protection circuit (30).

5. The over-temperature and over-current alarm protection circuit for motor according to claim 1, characterized in that, The alarm signal latch circuit (50) comprises: a direct current power supply VCC, an amplifier U4, a relay RL2, a diode D2, LED lamps L5 and L6, NPN triodes Q4 and Q6, a PNP triode Q5, a switch S1 and resistors R9, R10, R11, R12, R13, R14, R15 and R16; wherein the normally open input terminal of the relay RL2 is connected with the direct current power supply VCC, the upper port of the control terminal is connected with the emitter of the NPN triode Q4, the normally open output terminal of the relay RL2 is connected with the resistors R13, R14 and R15, the resistor R14 is connected with the base of the NPN triode Q6, the resistor R13 is connected with the collector of the PNP triode Q5 and the resistor R12, the emitter of the NPN triode Q6 is connected with the resistor R16 and the ground, the collector of the NPN triode Q6 is connected with the resistor R11 and the base of the PNP triode Q5, the emitter of the PNP triode Q5 is connected with the direct current power supply VCC and the resistor R11, the collector of the PNP triode Q5 is connected with the resistors R12 and R13, the resistor R12 is connected with the LED lamp L5, and the LED lamp L5 serves as an alarm signal prompt; the non-inverting terminal of the amplifier U4 is connected with the resistors R9 and R10, the resistor R10 is connected with the direct current power supply VCC and the collector of the NPN triode Q4, the inverting terminal of the amplifier U4 is connected with the LED lamp L6 and the output terminal of the over-temperature protection circuit, the output terminal of the amplifier U4 is connected with the NPN triode Q4, the emitter of the NPN triode Q4 is connected with the upper port of the control terminal of the relay RL2, and one end of the switch S1 is connected with the direct current power supply VCC and the collector of the NPN triode Q6.

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