CN202353179U - Three-phase protection device for screw-type water cooling unit - Google Patents
Three-phase protection device for screw-type water cooling unit Download PDFInfo
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- CN202353179U CN202353179U CN2011205485937U CN201120548593U CN202353179U CN 202353179 U CN202353179 U CN 202353179U CN 2011205485937 U CN2011205485937 U CN 2011205485937U CN 201120548593 U CN201120548593 U CN 201120548593U CN 202353179 U CN202353179 U CN 202353179U
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Abstract
The utility model discloses a three-phase protection device for a screw-type water cooling unit. The three-phase protection device comprises a compressor main loop (1) and a contactor control loop (2), and is characterized by further comprising a weak-current control loop (3), wherein the sampling terminals of current sampling devices in the weak-current control loop (3) are respectively arranged on any phase line of a three-phase line of a compressor and a corresponding power supply line; the output terminals of the current sampling devices are connected with the input terminal of a controller; the output terminal of the controller is connected with the coil of a relay KAI; and the contact of the relay KAI is connected with the contactor control loop (2). The three-phase protection device is insusceptible to current intensity, has high response speed and achieves more reliable protection.
Description
Technical field
The utility model relates to the screw-type water chiller technical field, specifically is a kind of three-phase protective device of screw-type water chiller.
Background technology
Screw-type water chiller is three phase supply, so the compressor in the screw-type water chiller needs perfect three-phase protective, generally should comprise sound attitude phase shortage, overload of compressor protection etc.The protection mechanism of domestic common employing at present need be used a plurality of detection parts; Comprise three-phase detection device, thermal relay, the built-in protector of compressor; Some switching value passages of when detecting fault, reserving through controller feed back to controller, because the actual load of the compressor of screw-type water chiller often has only 60%～70% of rated power, in phase shortage in such cases; Its phase-deficient operation electric current often can not surpass the setting value of thermal relay; Cause and in time to protect, and the three-phase detection device often can only detect power supply, can't monitor the inner phase shortage of unit.
The utility model content
The utility model technical problem to be solved is, provides and do not receive that size of current influences, response speed fast, the protection three-phase protective device of screw-type water chiller more reliably.
For solving the problems of the technologies described above; The three-phase protective device of the screw-type water chiller that the utility model provides; Comprise compressor major loop, contactor control loop; It also comprises the light current control loop, and the current sampling device sampling end in the light current control loop is located at any phase line and corresponding supply lines of compressor triple line respectively, and the current sampling device output connects the controller input; Controller output end connects the coil of relay K A1, and the contact of relay K A1 is connected with the contactor control loop.
After adopting above structure, the utility model compared with prior art has following advantage:
Current sampling device wherein one group the value of every group of line current and phase current Ic and I1, Ib and I3 or Ia and I2 of sampling; Be transferred to controller, when compressor start, operation, controller is through carrying out operational analysis to phase current and line current; Judge whether compressor is situation such as vacant phase starting, phase-deficient operation, overload; And control relay KA1 break-make protects, and the controller operational analysis does not receive the influence of size of current, and the controller information disposal ability is strong, response speed is fast.
As improvement, described current sampling device is first current transducer and second current transducer, has advantages such as high, simple in structure, good temperature characterisitic of accuracy height, integrated degree and stability.
As further improvement, described controller output end also connects the coil of relay K A2, and the contact of relay K A2 is connected with the alarm indicator light; Relay K A2 control circuit for alarming break-make; When described controller was judged compressor phase-deficient operation, vacant phase starting or overload, controller sent instruction simultaneously and gives relay K A2, the relay K A2 closing of contact; Thereby start the alarm indicator light, realize warning function.
As further improving, described controller is that model is the PLC of SC-80HC, can adapt to various abominable running environment, and antijamming capability is strong, good reliability.
Description of drawings
Fig. 1 is the utility model electrical block diagram.
Wherein, 1, compressor major loop; 2, contactor control loop; 3, light current control loop; 4, first current transducer; 5, second current transducer; 6, alarm indicator light.
Embodiment
Below in conjunction with accompanying drawing and embodiment the utility model is done explanation in further detail.
Three-phase protective device circuit structural representation by the utility model screw-type water chiller shown in Figure 1 can be known; It comprises compressor major loop 1, contactor control loop 2; It also comprises light current control loop 3; Current sampling device sampling end in the light current control loop 3 is located at any phase line and corresponding supply lines of compressor triple line respectively; The current sampling device output connects the controller input, and controller output end connects the coil of relay K A1, and the contact of relay K A1 is connected with contactor control loop 2.
Described current sampling device is first current transducer 4 and second current transducer 5.
Described controller output end also connects the coil of relay K A2, and the contact of relay K A2 is connected with alarm indicator light 6.
Described controller is that model is the PLC of SC-80HC.
Current transducer wherein one group the value of every group of line current and phase current Ic and I1, Ib and I3 or Ia and I2 of sampling is transferred to PLC, when the compressor star connection starts; When PLC detects any electric current is the electric current of any electric current of zero or any time point greater than a last time point; The judgement compressor is a vacant phase starting, and PLC sends instruction and gives relay K A1, and relay K A1 contact is broken off; Thereby break off the contactor control loop, realize the protection of compressor vacant phase starting;
And the ratio I c:I1 of preset compressor delta-connection line current of PLC and phase current or Ib:I3 or Ia:I2 1.732 (are commonly the conclusion of called optical imaging in the three-phase compressor; Here do not do too much argumentation); During the operation of compressor delta-connection, the value that detects Ic:I1 or Ib:I3 or Ia:I2 as PLC is not 1.732, judges the compressor phase-deficient operation; PLC sends instruction and gives relay K A1; Relay K A1 contact is broken off, thereby breaks off the contactor control loop, real compressor delta-connection phase-deficient operation protection;
Line current value or phase current values when the preset compressor of PLC normally moves; Any line current surpasses preset line current value or any phase current surpasses the lasting some minutes of preset line current value when PLC detects; Judge overload of compressor; PLC sends instruction and gives relay K A1, and relay K A1 contact is broken off, thereby breaks off the contactor control loop.The protection of realization overload of compressor.
The calculating process of each item protection is following:
1, compressor vacant phase starting protection
When compressor normally starts, start immediate current and be starting current (being generally 3～7 times of rated current, be 1/3 when directly starting when adopting the star connection reduced-voltage starting), along with the compressor starts rotation, winding current is dropped rapidly to normal running current.
When compressor scarce started mutually, the two-phase winding that does not lack was equivalent to be serially connected in the 380V power supply, can't form rotating magnetic field, and compressor can not start, and has short circuit current to flow through on this two-phase winding.Because of compressor can't start, electric current all is used for heating, and winding temperature acutely rises, and its resistance descends rapidly, and electric current continues to rise in this process, until high temperature winding is blown.
From the above, the normal startup of compressor is opposite with the electric current variation tendency of vacant phase starting.
In conjunction with above-mentioned analysis, the vacant phase starting protection scheme of compressor is following:
The compressor star connection is generally 3-7S start-up time, in the star connection start-up course, is taken to few two time points, and is as shown in Figure 5; Gather the line current Ic and the phase current I1 of these several time points of compressor through current transformer; When scarce L1 started mutually, I1=0, Ic became big; When scarce L2 started mutually, it is big that I1 and Ic become; When scarce L3 started mutually, it is big that I1 becomes, Ic=0.
Have above-mentioned analysis to get, in a single day PLC detects electric current is the electric current of the electric current of 0 or time point greater than a last time point, and just electric current is 0 or electrorheological when big; Be judged to be the compressor vacant phase starting; PLC sends instruction, and relay K A1 contact is broken off, thereby breaks off the contactor control loop; The while relay K A2 closing of contact, exportable alarm.
When line current and the phase current of sampling were Ib and I3 or Ia and I2, decision method was the same simultaneously, and result of determination is also in above-mentioned conclusion unanimity.
2, compressor phase-deficient operation protection
The ratio of applied compression machine delta-connection line current and phase current is 1.732 principle, like Fig. 2, and Ic:I1=Ib:I3=Ia:I2=1.732.
During the operation of compressor delta-connection, according to the difference of phase shortage point, its circuit can change thereupon, makes a concrete analysis of as follows:
1) during power supply L1 phase phase shortage, winding T1, T2 series connection back are parallelly connected with T3, two termination 380V～single phase poaer supplies, and circuit reduction is as shown in Figure 3, and electric current calculates as follows:
Ia=0, according to the parallel circuits operation principle,
I1=I3=I2×T2/(T1+T3)=0.5I2，Ib=Ic=I1+I2=1.5I2
Ia/I2=0，Ib/I3=3，Ic/I1=3
In like manner can get, when power supply L2 phase phase shortage, Ia/I2=3, Ib/I3=0, Ic/I1=3; When power supply L3 phase phase shortage, Ia/I2=3, Ib/I3=3, Ic/I1=0.
Can know by above calculating, no matter during L1, L2, L3 any phase power line phase shortage, Ic/I1 ≠ 1.732.
When 2) the T1 phase winding broke (like the loose contact of contactor main contacts A point), the T1 phase current was 0, and two phase windings have the electric current that differs 120 ° of electrical degrees in addition, and circuit reduction is as shown in Figure 4, and electric current calculates as follows:
I1=0 supposes I2=Ix (Φ=0 °), I3=Ix (Φ=120 °), then
Ic=I2+I3=1.732Ix，Ia=I3=Ix，Ib=I2=Ix
Ia/I2=1,?Ib/I3=1,?Ic/I1=∞
In like manner can get, when the T2 phase winding breaks, Ia/I2=∞, Ib/I3=1, Ic/I1=1; When the T3 phase winding breaks, Ia/I2=1, Ib/I3=∞, Ic/I1=1.
Can know by above calculating, no matter during T1, T2, T3 any phase winding broken string, Ic/I1 ≠ 1.732
In conjunction with above-mentioned analysis, the phase-deficient operation protection scheme of compressor is following:
Through the line current and the phase current (, can be Ic and I1, Ib and I3 or Ia and I2) of current transformer collection compressor, in the compressor delta-connection running like Fig. 2; In a single day PLC detects Ic/I1 ≠ 1.732, judges the compressor phase-deficient operation, and PLC sends instruction; Relay K A1 contact is broken off; Thereby break off the contactor control loop, the while relay K A2 closing of contact, exportable alarm.
When line current and the phase current of sampling were Ib and I3 or Ia and I2, decision method was the same simultaneously, and result of determination is also in above-mentioned conclusion unanimity.
3, overload of compressor protection
Gather electric current through current transformer, can monitor the overload situations of compressor equally, protection scheme is following:
Line current value or phase current values (line current when normally moving is established according to the different concrete conditions of looking of compressor horsepower with phase current) when the preset compressor of PLC normally moves; Current transformer is gathered line current and phase current, and any line current surpasses preset line current value or any phase current surpasses preset line current value T minute (T can oneself set, such as being made as 1) when PLC detects; Judge overload of compressor; PLC sends instruction, and relay K A1 contact is broken off, thereby breaks off the contactor control loop; The while relay K A2 closing of contact, exportable alarm.
Claims (4)
1. the three-phase protective device of a screw-type water chiller; Comprise compressor major loop (1), contactor control loop (2); It is characterized in that: it also comprises light current control loop (3); Current sampling device sampling end in the light current control loop (3) is located at any phase line and corresponding supply lines of compressor triple line respectively; The current sampling device output connects the controller input, and controller output end connects the coil of relay K A1, and the contact of relay K A1 is connected with contactor control loop (2).
2. the three-phase protective device of screw-type water chiller according to claim 1, it is characterized in that: described current sampling device is first current transducer (4) and second current transducer (5).
3. the three-phase protective device of screw-type water chiller according to claim 1, it is characterized in that: described controller output end also connects the coil of relay K A2, and the contact of relay K A2 is connected with alarm indicator light (6).
4. the three-phase protective device of screw-type water chiller according to claim 1, it is characterized in that: described controller is that model is the PLC of SC-80HC.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011205485937U CN202353179U (en) | 2011-12-26 | 2011-12-26 | Three-phase protection device for screw-type water cooling unit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011205485937U CN202353179U (en) | 2011-12-26 | 2011-12-26 | Three-phase protection device for screw-type water cooling unit |
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| Publication Number | Publication Date |
|---|---|
| CN202353179U true CN202353179U (en) | 2012-07-25 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011205485937U Expired - Lifetime CN202353179U (en) | 2011-12-26 | 2011-12-26 | Three-phase protection device for screw-type water cooling unit |
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| CN (1) | CN202353179U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105091186A (en) * | 2014-04-29 | 2015-11-25 | 珠海格力电器股份有限公司 | Phase sequence protection method and system for air conditioning unit |
-
2011
- 2011-12-26 CN CN2011205485937U patent/CN202353179U/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105091186A (en) * | 2014-04-29 | 2015-11-25 | 珠海格力电器股份有限公司 | Phase sequence protection method and system for air conditioning unit |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| ASS | Succession or assignment of patent right |
Owner name: WATERFURNACE SHENGLONG HVACR CLIMATE SOLUTIONS CO. Free format text: FORMER OWNER: AIMEI SHENGLONG (NINGBO) MACHINERY CO., LTD. Effective date: 20130531 |
|
| C41 | Transfer of patent application or patent right or utility model | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20130531 Address after: 315104 Zhejiang city of Ningbo province Yinzhou District investment center JINDA Road No. 788 Patentee after: WaterFurnace Shenglong HVACR Climate Solutions Co., Ltd. Address before: 315104 Zhejiang city of Ningbo province Yinzhou Industrial Park Jin Road No. 788 Patentee before: WFI (Ningbo) Machinery Co., Ltd. |
|
| CX01 | Expiry of patent term |
Granted publication date: 20120725 |
|
| CX01 | Expiry of patent term |