CN102664388A - Overheat protection circuit for asynchronous motor - Google Patents
Overheat protection circuit for asynchronous motor Download PDFInfo
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- CN102664388A CN102664388A CN2012101480740A CN201210148074A CN102664388A CN 102664388 A CN102664388 A CN 102664388A CN 2012101480740 A CN2012101480740 A CN 2012101480740A CN 201210148074 A CN201210148074 A CN 201210148074A CN 102664388 A CN102664388 A CN 102664388A
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- main motor
- stator winding
- protection circuit
- motor stator
- thermistor
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Abstract
The invention discloses an overheat protection circuit for an asynchronous motor. The overheat protection circuit comprises a main motor stator winding, wherein a heat-sensitive resistor switch is embedded into the main motor stator winding, and is connected with a power supply after being connected in series with an intermediate relay coil; the contact of the intermediate relay coil is connected with the power supply after being connected in series with another fan; the heat-sensitive resistor switch is a PTC (Positive Temperature Coefficient) heat-sensitive resistor; an intermediate relay is a normally-closed contact relay; the main motor stator winding is a three-phase winding; a heat-sensitive resistor switch is embedded into each phase of main motor stator winding; and the heat-sensitive resistor switch in each main motor stator winding is connected in series. Other fans can be started and shut down according to the temperature rise of a main motor, so that safe and reliable running of the main motor is ensured; and the overheat protection circuit has the advantage of saving electricity resource, and is widely applied to various motors.
Description
Technical field
The present invention relates to a kind of overheating protection circuit of asynchronous motor, relate in particular to the overheated air-cooled protective circuit of asynchronous motor.
Background technology
Asynchronous motor has in industrial and agricultural production extremely widely to be used; The loss that it time is produced in operation all changes heat energy into and makes that the motor feels hot; In order to guarantee that motor reliably working steady in a long-term must discharge heat; Otherwise it is aging to quicken insulating material, reduces its insulation property, energy conversion efficiency and useful life.
The most frequently used heat radiation type of cooling of asynchronous motor is utilize to ventilate to cooling off, and mainly comprises self cool, fans cold type certainly and he fans modes such as cooled.Be under the working conditions such as continuous running frequent starting, ambient temperature and ventilated environment be bad; Motor also adopts from the fan cooling and fans the type of cooling that cooling combines with him; Like motor application when Digit Control Machine Tool, the electrical control cubicles; All adopt aerofoil fan or ac fan to fan cooling fan, so that motor temperature and hottest spot temperature are controlled in the permissible value scope as him.
But existing he fan cooling or certainly fan combine him to fan in the cooling system; Supply with his Fan of main motor cooling air, no matter temperature rise, temperature and the ambient temperature of main motor, always continuously running continuously; And under most of environment; Temperature and the temperature rise that can guarantee main motor from Fan even self cooling mode are in the permissible value scope, and this moment is the in fact unwanted losses done of the fan electromotor of operation continuously, must cause the waste of power resource; Also bring the raising of whole system operating cost, it is also very uneconomical both to have wasted energy.
Summary of the invention
To the above-mentioned deficiency of existing in prior technology, technical problem to be solved by this invention provide a kind of can according to main motor temperature temperature rise automatic start-stop he the fan the asynchronous motor overheating protection circuit.
In order to solve the problems of the technologies described above; Asynchronous motor overheating protection circuit of the present invention; Comprise the main motor stator winding; Said main motor stator winding is embedded with thermistor switch, and said thermistor switch is connected with power supply with auxiliary relay coil series connection back, and said auxiliary relay contact is fanned motor series connection back with him and is connected with power supply.
In above-mentioned overheating protection circuit; Because the circuit design that adopts thermistor switch to connect with the auxiliary relay coil; And be embedded in temperature and the temperature rise that thermistor switch in the main motor stator winding can perception main motor stator winding, when temperature raise and when causing resistance to rise to the auxiliary relay coil losing electricity or electric and its contact is connected because the auxiliary relay contact is fanned motor with him and is connected; He fans motor must establish the beginning startup by cable; And the blast forced air of utilizing fan to produce is quickened to flow, and brushes heat-delivery surface, increases the heat-sinking capability of main motor greatly.Otherwise the auxiliary relay contact breaks off, and he fans the motor dead electricity and closes, and he quits work by Fan.In this structure; Through the temperature of the direct perception main motor stator of thermistor switch winding, and the disconnection or the connection of decision auxiliary relay contact, realize that then he fans the unlatching of motor or closes; Make it to determine him to fan the keying of motor according to main electric machine temperature rise; Not only guaranteed main motor can long-term work in the temperature range that allows, thoroughly avoided the overheated operation of main motor, even burnt out; And practiced thrift electric energy greatly, have and use advantage efficient, the saves energy resource.The characteristics that this overheating protection circuit is reasonable in design, circuit is simple, functional reliability is high are convenient to implement, and are practical.
Preferred implementation of the present invention, said thermistor switch are thermistor.The thermistor switch that adopts this semiconductor ceramic material to form, temperature coefficient is big, highly sensitive, reliable operation.
Further execution mode of the present invention, said main motor stator winding is three phase windings, all is embedded with thermistor switch in every phase main motor stator winding, the thermistor switch in each main motor stator winding is connected each other.This structure is applicable to threephase asynchronous, and thermistor switch can determine him to fan the motor operation according to the temperature of arbitrary stator winding, confirmed the reliability service of main motor.
Description of drawings
Below in conjunction with accompanying drawing and embodiment asynchronous motor overheating protection circuit of the present invention is done further explain.
Fig. 1 is the circuit diagram of a kind of embodiment of asynchronous motor overheating protection circuit of the present invention.
Among the figure, 1-power-line terminal plate, 2-main motor stator winding, 3-thermistor switch, 4-auxiliary relay, 5-he fans motor.
Embodiment
In circuit diagram shown in Figure 1, main motor is a threephase asynchronous, and main motor windings has three phase windings.This main motor windings 2 is connected through power-line terminal plate 1 and three phase mains.In each phase winding, all be embedded with thermistor switch 3, promptly temperature-sensitive resistance switch 3 is fitted with the winding coil next-door neighbour or is wrapped up by winding coil, so that the directly temperature and the temperature rise of perception winding coil.After the coil series connection of three thermistor switches 3 and auxiliary relay 4; Be connected in three phase mains the C phase (but also A mutually or the B phase) and the PE earth connection on, and the contact of auxiliary relay 4 with after he fans motor 5 series connection also with the C of three phase mains mutually on (but same A phase or B phase) and the PE earth connection.He fans motor 5 and is monophase machine, in order to drive his Fan.
When main motor is overheated for some reason; Main motor stator winding 2 appearance temperature raise; This moment, thermistor switch 3 was heated and resistance value rises to, auxiliary relay 4 coil losing electricities of series connection with it, contact KA-1 closure that it is normally closed; He fan motor 5 bring into operation and make main motor be able to very soon the heat radiation, make main Electrimotor ' reduce to allowed band.This overheating protection circuit just made motor be able to cooling protection through the directly internal temperature variation of the every phase winding of monitoring before overtemperature breaks through a certain preset temperature value.Simultaneously because the restorability of thermistor, the element that needn't more renew as Thermal Cutoffs after he Fan work a period of time; Main motor temperature is reduced to normal value; Thermistor switch 3 returns to low resistance state, and auxiliary relay 4 coil KA get electric, and KA-1 breaks off; He fans motor 5 and quits work again, has so not only protected main motor but also has reached energy-conservation purpose.
In another embodiment of the present invention; Be that with the foregoing description difference thermistor switch 3 is the NTC thermistor, this negative tempperature coefficient thermistor raises and the resistance minimizing with temperature; Corresponding with this, auxiliary relay 4 adopts the auxiliary relay of normally open contacts at this moment.
Above-mentionedly only enumerated preferred implementations more of the present invention, but the present invention is not limited thereto.Its thermistor switch can also adopt copper thermistor or platinum heat etc.As long as adopted motor windings to bury bag thermistor switch and relay, all should be regarded as falling in protection scope of the present invention.
Claims (5)
1. asynchronous motor overheating protection circuit; Comprise main motor stator winding (2); It is characterized in that: said main motor stator winding (2) is embedded with thermistor switch (3); Said thermistor switch (3) is connected with power supply with auxiliary relay (4) coil series connection back, and said auxiliary relay (4) contact is fanned motor (5) series connection back with him and is connected with power supply.
2. asynchronous motor overheating protection circuit according to claim 1 is characterized in that: said thermistor switch (3) is the PTC thermistor.
3. asynchronous motor overheating protection circuit according to claim 2 is characterized in that: said auxiliary relay (4) is the normally closed interlock relay.
4. according to claim 1,2 or 3 described asynchronous motor overheating protection circuits; It is characterized in that: said main motor stator winding (2) is three phase windings; All be embedded with thermistor switch (3) in every phase main motor stator winding (2), the thermistor switch (3) in each main motor stator winding (2) is series connection each other.
5. asynchronous motor overheating protection circuit according to claim 1 is characterized in that: said thermistor switch (3) is the NTC thermistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012101480740A CN102664388A (en) | 2012-05-15 | 2012-05-15 | Overheat protection circuit for asynchronous motor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012101480740A CN102664388A (en) | 2012-05-15 | 2012-05-15 | Overheat protection circuit for asynchronous motor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN102664388A true CN102664388A (en) | 2012-09-12 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2012101480740A Pending CN102664388A (en) | 2012-05-15 | 2012-05-15 | Overheat protection circuit for asynchronous motor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN102664388A (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2081596U (en) * | 1990-12-28 | 1991-07-24 | 李士华 | Electronic thermorelay |
| CN201075783Y (en) * | 2007-07-19 | 2008-06-18 | 宝山钢铁股份有限公司 | AC gear motor |
| CN202586287U (en) * | 2012-05-15 | 2012-12-05 | 江苏利得尔电机有限公司 | Overheat protection circuit of asynchronous motor |
-
2012
- 2012-05-15 CN CN2012101480740A patent/CN102664388A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2081596U (en) * | 1990-12-28 | 1991-07-24 | 李士华 | Electronic thermorelay |
| CN201075783Y (en) * | 2007-07-19 | 2008-06-18 | 宝山钢铁股份有限公司 | AC gear motor |
| CN202586287U (en) * | 2012-05-15 | 2012-12-05 | 江苏利得尔电机有限公司 | Overheat protection circuit of asynchronous motor |
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| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20120912 |