CN2152331Y - Thermal-sensitive over-temperature breaker for motor - Google Patents

Abstract

The utility model relates to a protector for the power cut with over temperature of an electric motor. A temperature measuring thermosensitive resistor is arranged in the electric motor. A current limiting resistor, a thermosensitive resistor and a potentiometer are connected in series in a circuit. A relay coil is connected with one-way controlled silicon in series, and the slide end of the potentiometer is connected with the control pole of the one-waycontrolled silicon. A pair of normally closed contacts of a relay are connected to in series the loop of a contactor coil by which the electric motor is controlled. When the temperature of the electric motor exceed the self safe temperature of the electric motor during running, the resistance value of the thermosensitive resistor suddenly drops, the one-way controlled silicon is triggered and switched on, electric current flows in the relay coil, and the normally closed contacts are switched off. The contactor coil losses electricity, contacts of the contactor coil are opened, and the electric motor is switched off.

Description

Thermal-sensitive over-temperature breaker for motor

The utility model relates to a kind of motor protecting device, can cut off motor power immediately automatically when motor temperature in service surpasses the inherently safe temperature, sends sound and light alarm simultaneously.

At present; known motor protecting device thermal relay; use the thermosensitive bimetal thermometric; promote guide plate by thermosensitive bimetal because of the overcurrent heated bending; and mend by temperature and to taste bimetal leaf and guide rod with movable contact and break disjunction, make the contactor coil of controlling motor its contact that cuts off the power supply open motor power is excised.Motor in service all is equipped with thermal relay, has emitted opium to burn the accident that thermal relay does not still cut off the power supply but motor still often occurs in producing, long term production proof thermal relay poor reliability.

The purpose of this utility model provides a kind of reliability height; need not to regulate, electron temperature-control formula motor protecting device simple in structure; when motor temperature in service surpasses the inherently safe temperature, can cut off motor power immediately automatically, send sound and light alarm simultaneously.

Motor temperature in service is violent suddenly to raise, and out of control is the immediate cause that motor burns.Therefore motor is moved in the inherently safe temperature, raise and cut off motor power when surpassing the inherently safe temperature immediately automatically when motor temperature is violent suddenly, the blocking-up thermal source is the effective measures that guarantee motor safety in service.

The purpose of this utility model is achieved in that the thermometric negative tempperature coefficient thermistor is contained in the motor stator winding overhang and closely contacts or be installed in the aperture of motor casing top with enamelled wire and closely contact with the motor casing metal.Negative tempperature coefficient thermistor two ends lead-in wires with cause the utility model after two long insulated conductors are electrically connected, in the pile crown that is electrically connected inside and outside two negative tempperature coefficient thermistors on the utility model support introducing circuit board.The utility model casing is overall plastic material, is made of two parts about support and the guard shield.Support is a rectangle, and respectively there is the inside and outside wiring pile crown that is electrically connected of four confessions front and back, and support the right and left respectively has a hole to be used for fixing complete machine.Respectively have a square projection circuit board to fix on it about inboard wall of base, guard shield is overall plastic rectangle.

In the circuit board in insulation case, the elementary pile crown that is electrically connected inside and outside two power supplys on the support of power transformer is connected on protected motor power fuse upper end.The secondary bridge rectifier input that connects of power transformer has reset button in the secondary loop, the bridge rectifier output also connects an electrochemical capacitor, after the electrochemical capacitor and connect a voltage stabilizing didoe and constitute DC power supply of the present utility model.By negative tempperature coefficient thermistor two end lines that motor is introduced, a termination current-limiting resistance R ₁, R ₁Another termination positive source, another termination multi-turn trimmer potentiometer resistive element one end of negative tempperature coefficient thermistor, another termination power cathode of multi-turn trimmer potentiometer resistive element, the order of multi-turn trimmer potentiometer sliding end is to the SCR control utmost point.The one-way SCR negative electrode connects power cathode, one-way SCR anode connection small general-purpose relay coil one end, another termination positive source of midget universal relay coil.Being electrically connected pile crown inside and outside two normally-closed contacts of a pair of normally-closed contact in first group of contact of midget universal relay on support seals in the contactor coil loop of control motor.A pair of normally opened contact in second group of contact of midget universal relay is electrically connected pile crown inside and outside two normally opened contacts on the support, seal in the ring coil loop, and the moving contact in the 3rd group of contact of midget universal relay meets current-limiting resistance R ₂An end, current-limiting resistance R ₂Another termination positive source, normally closed fixed contact connects green light-emitting diode positive pole, green light-emitting diode negative pole connects power cathode, often opens fixed contact and connects the Red LED1 positive pole, the Red LED1 negative pole connects power cathode.

Motor stator winding enamelled wire the end of a thread all welds with scolding tin.The scolding tin fusing point is 110 ℃.A class F insulation motor stator winding maximum safety temperature is 95 ℃.Determine that according to above 2 the utility model motor stator winding maximum safety temperature is 85 ℃ in the running, the motor casing maximum safety temperature is 65 ℃ in the running.

Be contained on the motor stator winding overhang enamelled wire for the thermometric negative tempperature coefficient thermistor.When making, the outage temperature of temperature-sensitive motor over-temperature circuit breaker sets up at 85 ℃.Be contained in the motor casing top metal aperture for the thermometric negative tempperature coefficient thermistor.When making, the outage temperature of temperature-sensitive motor over-temperature circuit breaker sets up at 65 ℃.

When motor in service because of power failure, during the own fault of electromotor overload or motor, the motor winding current sharply rises suddenly, electromotor winding temperature and motor casing temperature also sharply rise suddenly.The negative tempperature coefficient thermistor resistance that is contained in motor stator winding and the motor casing sharply descends suddenly.When motor temperature rises to the motor maximum safety temperature.Be added in electric current, voltage breakthrough one-way SCR triggering and conducting critical value that one-way SCR control is extremely gone up, the one-way SCR triggering and conducting.Midget universal relay coil midstream overcurrent, the normally-closed contact that seals in the midget universal relay in the contactor coil loop of controlling motor disconnects, its contact disjunction of contactor coil dead electricity, motor power cuts off, the blocking-up of motor thermal source.Seal in the normally opened contact closure of the midget universal relay in the ring coil loop, ring coil gets electric, and electric bell sends motor over-temperature power alarm sound.Normally-closed contact in the 3rd group of contact of midget universal relay disconnects green light-emitting diode and goes out, and the closed Red LED1 of normally opened contact is bright, shows to look motor overtemperature outage.So far realized the purpose that motor over-temperature outage in service, sound, light are reported to the police.

Because adopt such scheme, no matter which kind of fault takes place in motor in service, makes motor temperature surpass the inherently safe temperature.Temperature-sensitive motor over-temperature circuit breaker all can cut off motor power immediately automatically and send sound, light warning.Measure the motor temperature good reliability with the subzero temperature temperature coefficient thermistor, highly sensitive, safe temperature fixedly need not to regulate, and easy to use, used element is few, and is simple in structure.

Below in conjunction with drawings and Examples the utility model is further specified:

Figure (1) is circuit theory diagrams of the present utility model.

Figure (2) is a winding diagram of the present utility model.

Figure (3) is safe temperature mensuration figure of the present utility model.

In figure (1), B small power transformer, FWA reset button, D ₁-D ₄Rectifier diode, C electrochemical capacitor, D _WVoltage stabilizing didoe, R ₁Current-limiting resistance, R _tNegative tempperature coefficient thermistor, R _WThe multi-turn trimmer potentiometer, SCR one-way SCR, JTX midget universal relay, JTX ₁First group of contact of midget universal relay, JTX ₂Second group of contact of midget universal relay, JTX ₃The 3rd group of contact of midget universal relay, R ₂Current-limiting resistance, HED Red LED1, the green light-emitting diode of LED, the contactor coil of JC control motor, JC ₁The contactor self-locking contact of control motor.QA motor starting button, TA motor stop button, DL electric bell.

In Fig. 2, CWDDQ temperature-sensitive motor over-temperature circuit breaker, the inside and outside electrical connection pile crown of 1,2 AC power, the inside and outside pile crown that is electrically connected of 3,4 normally-closed contacts, the inside and outside pile crown that is electrically connected of 5,6 thermistors, inside and outside pile crown, the FWA reset button R of being electrically connected of 7,8 normally opened contacts _{T °}Negative tempperature coefficient thermistor, the contactor coil of JC control motor, JC ₁The contactor self-locking contact of control motor, JC ₂The main noddle on contactor of control motor, QA motor starting button, TA motor stop button, the D motor, RD fuse, DL electric bell, in Fig. 3,1 temperature-sensitive motor over-temperature circuit breaker, 2 radiator valves, 3 radiator valve thermistors, 4 temperature-sensitive motor over-temperature circuit breaker thermistors, 5 thermometric digital watch thermosensitive probes, 6 electric cups, 7 thermometric digital watch, 8 transformer oil, R _WThe multi-turn trimmer potentiometer, the green light-emitting diode of LED, HED Red LED1.

Embodiment is in conjunction with Fig. 1. Fig. 2. Fig. 3 describes, power transformer B elementary on support 1,2 two pile crown be connected on protected motor power fuse upper end, the secondary termination reset button FWA of power transformer, another termination bridge rectifier of reset button D ₁-D ₄Import an end, secondary another termination bridge rectifier input other end of power transformer.The bridge rectifier output also meets electrochemical capacitor C, after the electrochemical capacitor and meet voltage stabilizing didoe D _W, constitute this machine DC power supply, newly make or the motor of overhaul when rolling off the production line with thermistor R _tInsert in the enamelled wire slit of motor stator winding overhang, lead-in wire adds the long coat glass fibre sleeve and is drawn by motor connecting cartridge.Earlier bore dark 10mm at the motor casing top for the motor that uses on production line, diameter 5mm hole inserts in the hole thermistor and uses the insulating varnish sealing.Thermistor 5,6 liang of wiring pile crowns on support are introduced in the circuit board.Thermistor one termination current-limiting resistance R ₁, R ₁Another termination positive source, another termination multi-turn trimmer potentiometer of thermistor R _WResistive element one end, another termination power cathode of Rw resistive element, R _WThe sliding end order is controlled the utmost point to controllable silicon SCR, and the SCR negative electrode connects power cathode, SCR anode connection small general-purpose relay JTX coil one end.Another termination positive source of midget universal relay coil, JTX ₁In a pair of normally closed on support, 3,4 two pile crowns seal in the contactor coil loop of control motor, second group of contact JTX of JTX ₂In a pair of normally opened contact 7,8 two pile crowns on support seal in the electric bell DL loop.The 3rd group of contact of JTX, JTX ₃Moving contact meet current-limiting resistance R ₂One end, R ₂Another termination positive source, normally closed fixed contact connect green LED positive pole, and the LED negative pole connects power cathode, often open fixed contact and connect Red LED1 HED positive pole, and the HED negative pole connects power cathode.The motor safe temperature is measured: connect each device according to Fig. 3, take off temperature-sensitive motor over-temperature circuit breaker guard shield, radiator valve is transferred at 85 ℃, digital temperature measuring gauge switch is placed ON.Energized is when digital temperature measuring gauge shows 85 ℃ of apparents when constant.The careful multi-turn trimmer potentiometer of regulating makes the bright oppositely adjusting again of green light-emitting diode earlier, stops immediately to transfer when the bright green light-emitting diode of Red LED1 goes out.This moment, the outage temperature of temperature-sensitive motor over-temperature circuit breaker was exactly a motor stator line group maximum safety temperature.When thermistor is contained in the aperture of motor casing top, with transformer oil constant temperature multi-turn trimmer potentiometer in 65 ℃ of regulating circuit plates, make green light-emitting diode bright, oppositely regulate again when green light-emitting diode and go out, Red LED1 is bright, the disconnected temperature of motor over-temperature circuit breaker is promptly set up at 65 ℃, just the motor casing safe temperature.With insulating varnish multi-turn trimmer potentiometer envelope is irritated, thermistor is stamped with determined machine support duplicate numbers packed in the machine box.Safe temperature be fixed on 85 ℃ with safe temperature to be fixed on 65 ℃ of motor overtemperature prote effects identical, just provide convenience for installing." R in the utility model circuit ₁, Rt °, R _W" the thermometric branch road, available " the thermistor linear modules " that satisfies the requirement of this circuit parameter made the motor temperature probe, can save safe temperature and measure, and probe can general exchange head.

Claims (1)

1, a kind of motor protector is characterized in that: the elementary AC power that connects of power transformer, and the secondary bridge rectifier input that connects, the bridge rectifier output also connects an electrochemical capacitor, after the electrochemical capacitor, and meets a voltage stabilizing didoe, current-limiting resistance R ₁, a termination power positive pole, current-limiting resistance R ₁Another termination thermistor, the thermistor other end, connect potentiometer resistance body one end, another termination power cathode of potentiometer resistance body, the order of potentiometer sliding end is to the SCR control utmost point, relay coil one end, connect positive source, other end order is to the controllable silicon anode, and the one-way SCR negative electrode connects power cathode, and a pair of normally-closed contact in first group of contact of relay seals in the wire loop of control motor, a pair of normally opened contact in second group of contact of relay seals in the ring coil loop, and the moving contact in the 3rd group of contact of relay meets current-limiting resistance R ₂One end, current-limiting resistance R ₂Fixed contact in another termination positive source, the 3rd group of contact connects green light-emitting diodes positive pole, and green light-emitting diode negative pole connects power cathode, and the fixed contact of often opening in the 3rd group of contact connects the Red LED1 positive pole, and the Red LED1 negative pole connects power cathode.

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