CN1230816A

CN1230816A - Motor protector apparatus

Info

Publication number: CN1230816A
Application number: CN99104902A
Authority: CN
Inventors: 海野美津留; 佐藤竜彦
Original assignee: Texas Instruments Inc
Current assignee: Texas Instruments Inc
Priority date: 1998-03-31
Filing date: 1999-03-31
Publication date: 1999-10-06
Anticipated expiration: 2019-03-31
Also published as: CN1178359C; MY133443A; KR19990078374A; JPH11288649A

Abstract

A motor protector (1, 1a) includes a bimetal disc 8 having a movable contact 10 for opening and closing a circuit in a hermetic case (2). A second switch (23, 23A) with a fuse part (23c, 232) connects to the bimetal disc 8 in series to cut off the circuit by fusing the fuse part (23c, 232), when a predetermined excess current is generated. A connecting sheet part (23a, 230) of the second switch (23, 23A) is welded to the side face 5a of a header (5), and a connecting terminal pin (23b, 231) connects to a wire (25). An insulating case (26, 26A) covers the second switch (23, 23A) and an end pin (4).

Description

Motor protecting device

The present invention relates generally to the motor protecting device that uses in compressor of air conditioner, for example, be specifically related to be suitable for being placed on the motor protecting device of air compressor motor inside to be protected.

Fig. 4 (a) comprises a constant temperature dish strutting piece 103 to the motor protector 101 of the such prior art shown in 4 (c), and this strutting piece comprises just like the heater 103a within the body 102a shown in Fig. 4 (a) and 4 (b), that be arranged on a steel shell 102.Be fixed in strutting piece 103 an end one connect the end plate 105 that end pin 104 extend past outside the shell is arranged on the open end of shell 102.These pin 104 usefulness glass 106 also further seal with an epoxy pellet 107 with the body part electric insulation of the end plate of conduction.The constant temperature dish 108 that is formed by bimetallic and so on has and utilizes a material 109 to be fixed in the end of constant temperature dish strutting piece 103, and be provided with a movable contact 110 that is contained in opposed free ends, with the inwall that is installed in shell 1 02 on fixed contact 111 engagements and throw off.

For such motor protector is installed in the motor compressor (after this take as and be motor compressor) 100 of a sealing, the electric wire 112 of all freon resistant insulation is connected in and connects end pin 104 and shell 102.Motor protector 101 is placed in the insulating case 113, and is connected in all windings 114 (main winding 114a and auxiliary winding 114b) (shown in Fig. 4 (c)) in the rotor (not shown in FIG.) in the motor compressor 100.Its result, motor protector 101 is connected with the driving loop 130 of the motor compressor 100 that is connected in an AC power 115.

Owing to cause self heating of bi-metal plate 108 because of the epitrochanterian overload situation of motor compressor 100, at an overload of self heating that comprises heater 103a and bi-metal plate 108 or the ambient temperature abnormal high electric current in raising, make bi-metal plate 108 from being folded into male structure outside (not shown) just like the concave inward structure shown in Fig. 4 (b), disconnecting the electric current of motor, thereby prevented the possible loss of motor compressor 100.But there are following all restrictions in such motor protector of prior art.Under any above-mentioned abnormal conditions, motor protector 101 will repeatedly be connected and close, in case motor compressor 100 is compromised because of overheated.Unless the reason of the problem of searching, for example, to its place under repair, motor protector 101 will continue this motor compressor of protection under the situation of the period that surpasses the motor protector of assuring 101.In this case, motor protector will be above its life of product, finally make the fixed contact 111 of bi-metal plate 108 and movable contact 110 fusings and by seam together in make position, thereby produce a kind of state of electric current without interruption.Consequently, the winding 114 in the motor compressor 100 is overheated, and the insulating resin of winding 114 will finally melt, thereby make all windings 114 be in short-circuit condition, finally causes the burning out of winding 114 of motor compressor 100.Final produce for the cigarette ash of carbide can be attached to self the glass part of fulcrum post (3 is not shown among the figure), thereby destroyed the insulation between all fulcrum posts.In addition, in the worst case, on the surface of the glass of destroyed insulation, produced the conduction trace, and because the heating of electric current makes the softening and thawing of the glass part of all fulcrum posts, and may finally burn out all fulcrum posts, no longer can bear the internal pressure of motor compressor 100 to cause them.

This class motor protector ties up to the rotor that is connected in motor compressor 100 on the winding 114 by utilizing a rope; according to traditional technology; stress concentrates on the insulating sleeve in all wiring petiolareas; the special outside at end plate 105; its possible consequence is breaking of insulating sleeve 113, thus the generation problem.Occur in insulating sleeve 113 if break, just can between motor protector 101 and winding 114, produce a short circuit, thereby can not measure the abnormal state of motor compressor 100, and in the normal operation that can hinder motor compressor 100 in some cases.

An object of the present invention is: overcome the defective of above-mentioned prior art, and a motor protector is provided,, also can prevent to form a final dangerous situation even this motor protector is welded in together at all contacts.Another object of the present invention is: a motor protector is provided; this motor protector can not cause in the insulating case barrier part related with this motor producing any phenomenon of breaking and so on, thereby possible short circuit takes place all windings that prevent motor to be protected.A further object of the present invention is: a motor protector with a reliable switch is provided.

In brief, according to the present invention, one first switch contains a movable contact that connects in a circuit, be used for opening or closed this circuit when a dish is made action for response flow through the temperature of the value of the electric current of this circuit and the air in an aeroseal shell.One second switch is connected in series with first switch, is used for for good and all being disconnected this circuit by one by the overcurrent fusing of a regulation and the fuse part that is provided at outside the above-mentioned shell by whole shape.Under the situation of all contacts fusing of first switch, then the coil short owing to motor produces a bigger electric current.But, according to the present invention, the fuse partial melting of second switch, the driving loop of motor has for good and all been disconnected, thereby has stopped the startup of motor.Therefore, just can prevent that the hermetic motor compressor from may burn out or any may be to the damage of sealed wiring end.Consequently, just prevented carbide itself be attached to the sealed wiring end near, and can prevent because breaking of causing of the reduction of the insulating effect of glass capsulation.During normal running, the heating of second switch is little to the influence of the primary characteristic of motor protector, thereby owing to being located at second switch outside the shell and being away from first switch, so can obtain a high-precision motor protector.In addition, because second switch is away from first switch, even the required magnitude of current of fusing fuse part has changed, its heating is little to the influence of the characteristic of first switch.Just therefore, enable to proofread and correct the fusion current of second switch with the value of any selection.

According to another characteristics of the present invention; a guard shield part made from a kind of electrical insulating material has covered the fuse part of second switch at least; like this, under the situation of the winding that this motor protector is lain in motor to be protected with a rope, can not make second switch distortion or short circuit yet.Even under the situation that the fuse of second switch partly is melted,, also can keep this circuit to be cut off because this melt portions is covered by a screen.

According to characteristics more of the present invention, shielding part has covered the connection end pin that stretches out shell, makes under the situation of the winding that this motor protector is lain in motor to be protected with a rope, also can not make to connect end pin distortion or short circuit.The external diameter of this shielding part is substantially equal to the external diameter of the shell with maximum outside diameter, thereby does not have some shapes space jumpy to prevent producing the possibility that stress is concentrated at some non-support sections of insulating sleeve.So, be installed in this insulating sleeve and restrict at this motor protector and lie under the situation of motor winding, make the possibility minimum of crack growth with one.

According to another characteristics of the present invention, the available low electrical resistant material of fuse part of second switch is made, this fuse part is configuration like this, promptly, do lessly in a position of selecting its cross section, make the heat that during its normal running, sends less, the possibility of not having the heating of " red-Re " point takes place, consequently, for example, even the cooling agent at sealing type motor compressor directly touches under the situation of second switch, though cooling agent may damage its quality, it can not produce adverse influence to cooling agent yet.

To propose other purposes of the present invention, characteristics and advantage in the specification below, and all accompanying drawings below engaging will become more obvious after seeing this description.

Be comprised in all accompanying drawings interior and that consist of the part of specification and represented all embodiment of the present invention.All accompanying drawings are:

Fig. 1 (a) is the cutaway view of an expression according to the internal structure of a motor protector of one embodiment of the invention, expresses the radome that an insulating sleeve and usefulness hacures are represented among the figure;

Fig. 1 (b) is the elevational cross-sectional view of protector and the sleeve pipe of Fig. 1;

Fig. 1 (c) is a schematic circuit diagram, has represented the scheme in motor driven loop of the motor protector of employing Fig. 1 (a) and 1 (b);

Fig. 2 (a) is a front view, has represented the appearance of the motor protector made according to Fig. 1 (a) and 1 (b) and the radome that part is analysed and observe;

Fig. 2 (b) is a vertical view, has represented Fig. 1 (a) and the motor protector of 1 (b) and the appearance of radome;

Fig. 2 (c) is a left view, has represented the appearance of the motor protector of Fig. 2 (b);

Fig. 2 (d) is identical with Fig. 2 (b), but has cut radome;

Fig. 3 (a) is a vertical view, and part has been analysed and observe another embodiment of motor protector made in accordance with the present invention, and protector has wherein rotated 180 ° with respect to all accompanying drawings of first embodiment;

The front view of the motor protector of Fig. 3 (a) that Fig. 3 (b) is partly analysed and observe;

Fig. 4 (a) is a cutaway view, has represented the internal structure according to a motor protector of the prior art manufacturing that an insulating sleeve is arranged;

Fig. 4 (b) is the front view of the motor protector of Fig. 4 (a) of representing in cutaway view;

Fig. 4 (c) is a circuit diagram, has represented the scheme in a motor driven loop, and a motor protector according to prior art has been adopted in this loop.

Shown in Fig. 1 (a) and 1 (b), one internal structure that is similar to the example of above-mentioned traditional prior art is arranged according to the motor protector 1 of first embodiment of the invention manufacturing.In other words, in vertical shell 2 that the suitable material of a usefulness such as steel are made, be provided with a vertical dish strutting piece 3 with heating element 3a that a kind of high-resistance metal of a usefulness makes.One end of this dish strutting piece 3 is fixed in an end pin 4, and to be connected with an external loop, this end pin 4 stretches out outside the end plate 5, and this end plate 5 has the conduction collar flange in the open-mouth setting of shell 2.Annular gap between this flange of end pin 4 that connects and end plate 5 is sealed with an insulating glass material seal spare 7.If necessary, coated one epoxy pellet 7 on the outer surface of this glass seal 6.In manufacture process, in shell 2, import inert gas usually.The prominent Moving plate of one constant temperature utilizes a welding block 9 to be fixed in a side (in Fig. 1 (b) at lower surface) of dish strutting piece 3 as bi-metal plate 8.This bi-metal plate is engaged and makes with a free-ended movable contact 10 that for example is fixed in its distally by the discoid plate that usefulness joint steel and copper lamina form.One fixed contact 11 is installed in the inwall of shell 2, and align with the movable contact 10 of bi-metal plate 8, movable contact 10 is by the action of bi-metal plate 8, changes to a protruding disk shape opposite, (not shown) up and with fixed contact 11 engagements with throw off from the recessed disk shape down of one shown in Fig. 1 (b).

The motor protector 1 of Zhi Zaoing is placed in the motor compressor 50 (shown in Fig. 1 (c)) according to this embodiment.Shown in Fig. 1 (a) and 1 (b), in the time of in motor protector is placed on motor compressor 50, it is placed in the electric insulation sleeve 20, and this sleeve appropriate resin is made as polyester.The insulated electric conductor 22 of a freon resistant is by the 21 connection end pins 4 that are connected in this motor protector 1 of clamping.

The second switch 23 just like fuse that will talk about below is welded on the side 5a of the end plate 5 of shell 2, and clamping by one again 24 makes the insulated electric conductor 25 of a freon resistant be connected with this second switch 23.Such structure allows bi-metal plate 8 to connect with second switch.Be noted that: second switch 23 is placed in an electric insulation shell or the shielding part 26, and this be will be described below.

Shown in Fig. 1 (c); for example bi-metal plate 8 is connected in winding 51 (main winding 51a and auxiliary winding 51b do not express in the accompanying drawings) in motor compressor to be protected 50; meanwhile; second switch is connected in an AC power 52, thereby motor protector 1 can be connected with the driving loop 30 of motor compressor 50.Numbering 53 expressions among the figure are used for the electric capacity of motor start-up.

The second switch 23 of Zhi Zaoing is by a kind of low electrical resistant material (resistance range is approximately the 1.8-9.0 ohm meter) according to this embodiment, makes as copper alloy and so on.End 23a installs thin slice as one and utilizes and is welded to connect on the cylindrical side 5a of the end 5 of shell 2.Relative end 23b is as terminals, and it has the step of a skew of radially extending or formation in the middle of both ends inwardly.Integrally formed one crooked shape between installation end 23a that the fuse part 23c that one cross-sectional area reduces is configured as at second switch 23 and the terminal portion 23b is essentially U-shaped (seeing Fig. 2 (d)) as shown.

Insulation shielding spare 26 above-mentioned is by suitable material such as heat reactive resin, make as phenolic resins or unsaturated polyester resin, and for example be configured as a hollow cap, one end of this cap opens wide at the 26a place and roughly is configured as slightly than little one avette in the end 5 of shell 2, and this open section 26a contacts with the end surfaces 5b of end 5.On shielding part 26, form a conical surface 26c, cross section is roughly dwindled gradually along the direction that moves to end surfaces 26b.The fuse part 23c of second switch 23 is arranged on the cavity 27 interior (seeing Fig. 2 (a) and 2 (d)) that an end plate 5 that is insulated shielding part 26 and shell 2 surrounds, and covers or shields thereby be insulated shielding part 26.The terminal portion 23b of second switch 23 is positioned on 26 li of insulation shielding spares by a groove, and protrudes from outside the end surfaces 26b in a side relative with open end 26a.The terminal portion 23b of second switch 23 is fixed in this insulation shielding spare 26 suitably, thereby this insulation shielding spare 26 can be held with the main body 2a of shell 2.The terminal portion 23b of second switch 23 is located at a position away from insulation shielding spare 26, and making provides one for the space (seeing Fig. 2 (c) and 2 (d)) that connects freon resistant electric wire 25.Therefore, formed a hole 26d (seeing Fig. 2 (c)), be used for making freon resistant electric wire 25 (seeing Fig. 1 (b)) to pass shielding part 26 with being connected end pin 4 connections.

According to this embodiment, in case motor compressor 50 broken short circuits, thereby produce a big electric current, cause the movable contact 10 and the fixed contact 11 of bi-metal plate 8 to be welded in together, the fuse part 23c of second switch 23 is melted, with the permanent driving loop 30 that disconnects motor compressor 50, thereby prevent that motor compressor from being burnt out or damaging the terminals of sealing etc.In addition, will prevent to make carbide to arrive near terminals of sealing and follow and pass through glass seal.

Utilization is positioned second switch 23 position away from bi-metal plate 8 outside shell 2; the heating of second switch during the electric motor normal working 23 to the calibration characteristics, of motor protector (bi-metal plate 8 in the overload and the protective feature under a kind of malfunction) influence be minimum, thereby might obtain a high-precision motor protector.In addition, because second switch 23 is away from bi-metal plate 8, even the calibration value of the fusion current of fuse part 23c has been changed, heating is little to the influence of the characteristic of bi-metal plate 8, therefore, may be with the fusion current of the value calibration fuse part 23c of any selection.Be insulated shielding part 26 and cover in view of connecting end pin 4 and second switch 23, utilizing a cord motor protector to be lain under the situation of winding of motor compressor 50, can prevent second switch terminals 23 or connect the short circuit or the distortion of end pin 4.In addition, even under the situation that fuse part 23c is melted by an overcurrent,, just can make the state that the loop remains on disconnection that drives because puddle is insulated shielding part 26 and covers.Because the space that insulation shielding spare 26 is slightly smaller than end plate 5 and does not have an opening jumpy of some shapes surpasses this end plate; utilizing a cord motor protector 1 to be installed under the situation in the insulating sleeve 50; make local stress become minimum, and can prevent possible crack growth.Say that more specifically a conical surface 26c forms towards end surfaces 26b, near the angle of bend of insulating sleeve 20 outside end plate 5 becomes less, thereby has reduced the concentrated of stress, the development on more preventing from effectively to break in insulating sleeve 20.Because fuse part 23c is made up of low electrical resistant material such as copper alloy, less at the heat that in second switch 23, produces during the normal running, can not cause a kind of " red-Re " state.Even the cooling agent at motor compressor 50 directly is contacted with second switch 23, also can not produce the influence of discord to cooling agent, as degenerating of its quality etc.The characteristics of puddle 23c that form on it by replication, fuse terminals 23 make and can obtain a motor protector with so good function as mentioned above, and with compare according to the motor protector of prior art can increased in size.

Consult the embodiment shown in Fig. 3 (a) and 3 (b), by the numbering identical with the corresponding part use of above-mentioned first embodiment described the following examples.About Fig. 3 (a), 3 (b), second switch 23A through design make sheet segment 230 is installed can be identical with the situation of the thin slice 23a of first embodiment, utilize the side 5a of the end plate 5 that is fixedly welded on shell 2.Second switch 23A comprises installation sheet segment 230, a terminal portion 231 and a fuse part 232.Second switch 23A does not have the step part of first embodiment, extends longitudinally more compared with second switch 23, thereby can make its main body 2a extension along shell 2.Insulation shielding spare 26A is provided with to such an extent that make two facing surfaces that closely cover second switch 23A.On the surface of second switch 23A (upper surface among Fig. 3 (b)), a plurality of protrusions 233 are set, these protrusions are adapted to fit in the marginal portion of opening wide that insulation shell 26A goes up the engaging hole 260 that forms, giving insulation shell 26A the location, and meanwhile between the top 261 of fuse terminals 23A and insulation shielding spare 26A, provide a predetermined gap.In addition, on another surface of second switch 26A (lower surface among Fig. 3 (b)), a plurality of support protrusion things 234 are set.Since the existence of protrusion 234, an intrinsic predetermined gap between the lower part 263 of second switch 26A and insulation shielding spare 26A.Be noted that: if required, insulation shell 26A can form like this, that is, as at first embodiment, it has covered connection end pin 4, even not shown at Fig. 3 (a) and 3 (b).

So second embodiment is except the advantage with the damage that burns out or dock line end that can prevent motor compressor 50 and so on, an advantage that also provides is to make the length of a motor protector the shortest.Identical with in first embodiment of other parts, function and effect like this, just needn't describe in detail at this.The present invention is not limited to the mode of above-mentioned example, can revise with several different methods.For example, can revise suitably second switch fuse part shape or set the value of electric current, to meet the situation of motor to be protected etc.In addition, can use the material of the material of stanniferous (Sn) for example as the fuse part.In addition, the installation site of

second switch

23 and 23A is not limited to the side 5a of end plate, and can for example be installed on the terminals surface 5b of end plate 5.But,, as described in above-mentioned all embodiment, preferably they are installed on the side 5a of end plate 5 for fuse

second switch

23 and 23A accurately are fixed in shell.According to top the present invention who has described, a motor protector is provided, even this motor protector welds, also can prevent to form a final dangerous situation between all contacts.In addition, when the installation sleeve barrier part, can prevent possible development of crackle and so on, this motor protector is set in this sleeve member, and this motor protector is located on the motor of band protection.The present invention just, the contrast prior art, appended all claims can be done to explain as far as possible widely, and comprise these variations and modification.

Claims

1. motor protector, it comprises that one limits a cavity and the external conductive casing of an open end is arranged,

One first switch, it comprises: one is installed in the fixing electric contacts that engages with its electricity in this shell, one is placed in the conducting end plates of this open end with closed this cavity, one extend through this end plate and with the end pin of its electric insulation, one at the dish supporter that is installed in this cavity on this end pin, one temperature response dish and one is installed in the movable electrical contacts on this temperature response dish, this temperature response dish can cut off when movable contact and fixed contact are thrown off between the contact disengaged position that this circuit uses and moving to set up the contact position of engagement that a circuit uses and between movable contact and the fixed contact one

One second switch; it comprises an electric-conductor; this electric-conductor is connected in this protector and has one first link and one second terminals; between first end and second end, be the part that a cross section dwindles; this link one of is fixed in this end plate and this shell, and the part that this cross section dwindles is located at outside this shell, thereby; the partial melting that one overcurrent of selecting will make this cross section dwindle is with this circuit of permanent cut-out.

2. motor protector as claimed in claim 1 is characterized in that, also comprises the shielding part of an electrical insulating material, and it is connected in end plate and has covered the part that cross section reduces.

3. motor protector as claimed in claim 2 is characterized in that the shielding part of electrical insulating material has also covered at least a portion that extends through the end pin of end plate outside shell.

4. motor protector as claimed in claim 2; it is characterized in that; this motor protector has a length, and the external diameter of external conductive casing and end plate changes to a maximum along the length of this motor protector, and the external diameter of electric insulation shielding part is substantially equal to the maximum outside diameter of external conductive casing and end plate.

5. motor protector as claimed in claim 1 is characterized in that the electric-conductor of second switch is made by a kind of low electrical resistant material.

6. motor protector as claimed in claim 1 is characterized in that, the shape of the part that cross section reduces is a U font basically.

7. a motor protector is characterized in that,

One first switch, it comprises a movable contact in circuit, is used for opening or closing when a dish moves between a contact position of engagement and a contact disengaged position according to the temperature of current value that flows through and the air in an air impervious shell circuit; And

One second switch, its integral body are located at outside the above-mentioned shell, and it has a fuse part, and this part is connected with described first switch, with by by one the regulation overcurrent melt and this circuit of permanent cut-out.

8. motor protector as claimed in claim 7 is characterized in that, the shielding part that the connection end pin of protrusion shell is made by an insulating material covers.

9. motor protector as claimed in claim 7 is characterized in that, the shielding part that the part of fuse at least of second switch is made by an insulating material covers.

10. motor protector as claimed in claim 9 is characterized in that, the external diameter of insulating part is substantially equal to the diameter of the excircle part with maximum gauge of shell.

11. motor protector as claimed in claim 7 is characterized in that, described second switch is made by a kind of low electrical resistant material, and a fuse partly reduces cross-sectional area by part and forms.

12. motor protector as claimed in claim 7 is characterized in that, the fuse part of second switch is a U font basically.