A kind of control circuit of geothermal utilization
Technical field
The present invention relates to a kind of electronic circuit, be related specifically to temperature-control circuit and open-phase protection circuit.
Background technology
In places such as agricultural greenhouse, floriculture greenhouse, textile manufacturing workshops, need to keep constant temperature, winter need provide heating installation, and summer need provide cold air, to build the greenhouse being conducive to greenhouse crops, flower growth, or the production environment of favourable raising quality of textile products and output.
Agricultural greenhouse is a kind of framework structure of film with heat-insulating property, and its appearance makes people can have vegetables in improper season and fruit.General agricultural greenhouse uses the skeleton of bamboo structure or steel construction, is covered with one or more layers thermal insulation plastic film above, material is thus formed a greenhouse space.The loss of the carbon dioxide that adventitia stops inner vegetable growth to produce well, makes to have good heat insulation effect in canopy.When night or the rainy weather in winter, the temperature in agricultural greenhouse is too low, and unfavorable fruits and vegetables growth, affects fruit-vegetable quality and output.
Utilize underground heat to heat to agricultural greenhouse, floriculture greenhouse or textile manufacturing workshop and there is the important meaning of energy-conservation and GHG emissions mitigation, in the winter time, when the temperature in above-mentioned place is too low, draw up with pump handle geothermal water, heat release is carried out in above-mentioned place in a looping fashion again, to keep constant temperature by heating radiator; In summer, when the temperature in above-mentioned place is too high, underground cold water is drawn up and is absorbed heat in above-mentioned place by heating radiator, to keep constant temperature.In order to make the place such as agricultural greenhouse, floriculture greenhouse, textile manufacturing workshop keep constant temperature and save the energy, need a kind of thermostatic control switch being applicable to the application of above-mentioned place.
Summary of the invention
The object of the invention is the control circuit that a kind of geothermal utilization will be provided, be adapted at applying in agricultural greenhouse, floriculture greenhouse or textile manufacturing workshop, realize automatically controlling, terrestrial heat utilization system is rationally run, for the environment of favourable production is built in agricultural greenhouse, floriculture greenhouse or textile manufacturing workshop, save manpower and avoid waste of energy.
The control circuit of a kind of geothermal utilization of the present invention, it is characterized in that control circuit is by power circuit, information-processing circuit, control output circuit composition and open-phase protection circuit composition, in power circuit: the primary coil of rectifier transformer (TC) is connected to the phase line input end (2) of power supply and the zero line input end (1) of power supply, the secondary coil of rectifier transformer (TC) is connected to two input ends of single phase bridge type rectifier circu (VD), the positive pole of single phase bridge type rectifier circu (VD) is connected to filter capacitor a(C1) positive pole and the input end of integrated package of pressure-stabilizing (IC1), output terminal and the filter capacitor b(C2 of integrated package of pressure-stabilizing (IC1)) positive pole be connected after form DC supply (V+), the negative pole of single phase bridge type rectifier circu (VD), filter capacitor a(C1) negative pole, filter capacitor b(C2) negative pole be connected with the earth terminal of integrated package of pressure-stabilizing (IC1) after form ground wire, in information-processing circuit: feed end (5) is connected to DC supply (V+), lower limit temperature signal end (3) is connected to isolating diode a(V2) anode, ceiling temperature signal end (4) is connected to isolating diode b(V3) anode, isolating diode b(V3) negative electrode be connected to not gate b(IC3) input end, not gate b(IC3) output terminal be connected to isolating diode d(V5) anode, isolating diode d(V5) negative electrode and isolating diode a(V2) negative electrode be connected to not gate a(IC2) input end, not gate a(IC2) output terminal be connected to isolating diode c(V4) anode, isolating diode c(V4) negative electrode be connected to not gate b(IC3) input end, control in output circuit: drive resistance a(R3) the first pin be connected to isolating diode a(V2) negative electrode and isolating diode d(V5) negative electrode, drive resistance a(R3) crus secunda be connected to triode a(VT1) base stage, triode a(VT1) emitter be connected to ground wire, triode a(VT1) collector be connected to clamp diode a(V6) anode and the second end of the first relay coil (K1), clamp diode a(V6) negative electrode and the first end of the first relay coil (K1) be connected to DC supply (V+), the first end of the first relay normally open contact (K3) is connected to control end a(9), second end of the first relay normally open contact (K3) is connected to control end b(10 by the normally closed contact (K5) of the second relay), in open-phase protection circuit: by commutation diode a(V7), commutation diode b(V8), commutation diode c(V9), commutation diode d(V10), commutation diode e(V11) and commutation diode f(V12) form three-phase bridge rectifier circuit, phase line test side a(6) be connected to commutation diode a(V7) anode and commutation diode b(V8) negative electrode, phase line test side b(7) be connected to commutation diode c(V9) anode and commutation diode d(V10) negative electrode, phase line test side c(8) be connected to commutation diode e(V11) anode and commutation diode f(V12) negative electrode, commutation diode b(V8) anode, commutation diode d(V10) anode and commutation diode f(V12) anode be connected to ground wire, commutation diode a(V7) negative electrode, commutation diode c(V9) negative electrode and commutation diode e(V11) negative electrode be connected to divider resistance a(R4) the first pin, divider resistance a(R4) crus secunda be connected to divider resistance b(R5) the first pin and sampling diode (V13) negative electrode, divider resistance b(R5) crus secunda be connected to ground wire, the anode of sampling diode (V13) is connected to triode b(VT2 by biasing resistor (R6)) base stage, first pin of time delay resistance (R7) is connected to DC supply (V+), the crus secunda of time delay resistance (R7) is connected to triode b(VT2) collector, the positive pole of delay capacitor (C3), not gate c(IC4) input end and the first end of the first relay normally closed contact (K2), triode b(VT2) emitter, the negative pole of delay capacitor (C3) and the second end of the first relay normally closed contact (K2) are connected to ground wire, not gate c(IC4) output terminal be connected to not gate d(IC5) input end, not gate d(IC5) output terminal be connected to drive resistance b(R8) the first pin, drive resistance b(R8) crus secunda be connected to triode c(VT3) base stage, triode c(VT3) emitter be connected to ground wire, triode c(VT3) collector be connected to clamp diode b(V14) anode and the second end of the second relay coil (K4), clamp diode b(V14) negative electrode and the first end of the second relay coil (K4) be connected to DC supply (V+), the first end of the second relay normally closed contact (K5) is connected to the second end of the first relay normally open contact (K3), second end of the second relay normally closed contact (K5) is connected to control end b(10).
In the present invention, at not gate b(IC3) input end and ground wire between You Bang road resistance (R2), current limiting resistance (R1), pilot lamp diode (V1) and buzzer (Y) in control circuit, second relay comprises normally opened contact (K6), first pin of current-limiting resistance (R1) and the input end of buzzer (Y) are connected to DC supply (V+), current-limiting resistance (R1) crus secunda is connected to the anode of pilot lamp diode (V1), the negative electrode of pilot lamp diode (V1) and the output terminal of buzzer (Y) are connected to the first end of the second relay normally open contact (K6), and the second end of the second relay normally open contact (K6) is connected to ground wire, not gate a(IC2), not gate b(IC3), not gate c(IC4), not gate d(IC5) share a not gate digital integrated circuit, the power end of digital integrated circuit is connected to DC supply (V+), and the earth terminal of digital integrated circuit is connected to ground wire, the outer of control circuit is with electric contact thermometer (TK), the indicator Electrode connection of electric contact thermometer (TK) is to feed end (5), the lower limit Electrode connection of electric contact thermometer (TK) is to lower limit temperature signal end (3), and the upper limit Electrode connection of electric contact thermometer (TK) is to ceiling temperature signal end (4), the outer of control circuit is with contactor, electrothermal relay (FR), three-phase and four-line supply line and water circulating pump, contactor comprises coil (KM) and three groups of main contacts switches, three-phase and four-line supply line comprises wire a(U), wire b(V), wire c(W) and zero line (N), the zero line input end (1) of control circuit is connected on the zero line (N) of supply line, the phase line input end (2) of control circuit is connected to wire a(U) on, the first end of contactor coil (KM) is connected to wire c(W) on, second end of contactor coil (KM) is connected on the switch first end of electrothermal relay (FR), switch second end of electrothermal relay (FR) is connected to the control end a(9 of control circuit), the control end b(10 of control circuit) be connected to wire b(V) on, the phase line test side a(6 of control circuit), phase line test side b(7) and phase line test side c(8) be connected respectively on the three phase electric machine terminals of water circulating pump, the upper end of three groups of main contacts switches of contactor is connected respectively to wire a(U), wire b(V) and wire c(W) on, the lower end of three groups of main contacts switches of contactor is connected on the three phase electric machine terminals of water circulating pump by the leading body of electrothermal relay (FR).
When the present invention applies, wire a(U), wire b(V) and wire c(W) be connected to the phase line a(L1 of power supply by QS. automatic cut-off switch), the phase line b(L2 of power supply) and the phase line c(L3 of power supply) on, the temperature-sensitive bag of electric contact thermometer (TK) is arranged in agricultural greenhouse, indicator electrode, lower limit electrode and upper limit electrode is had in electric contact thermometer (TK), in the winter time, the lower limit temperature of electric contact thermometer (TK) is arranged between 12 °-15 °, the ceiling temperature of electric contact thermometer (TK) is arranged between 18 °-20 °; In summer, the lower limit electrode of electric contact thermometer (TK) is changed into and is connected to ceiling temperature signal end (4), the upper limit electrode of electric contact thermometer (TK) changes into and is connected to lower limit temperature signal end (3), the lower limit temperature of electric contact thermometer (TK) is arranged on 25 °, the ceiling temperature of electric contact thermometer (TK) is arranged on 28 °.For the thermostatic control in winter of agricultural greenhouse, during work, when temperature in agricultural greenhouse drops to the lower limit temperature of setting, the indicator of electric contact thermometer (TK) touches lower limit electrode, high level is by lower limit temperature signal end (3) and isolating diode a(V2) enter into triode a(VT1) base stage and not gate a(IC2) input end, make triode a(VT1) conducting and make not gate a(IC2) output terminal be low level, make not gate b(IC3) input end be low level, not gate b(IC3) output terminal be high level, triode a(VT1) after conducting, first relay coil (K1) is energized, first relay normally open contact (K3) adhesive is energized, start cycles water pump operation, pumping underground hot water is heated to agricultural greenhouse by heating radiator in a looping fashion, temperature in agricultural greenhouse raises along with the operation of water circulating pump, the indicator electrode of electric contact thermometer (TK) leaves lower limit electrode, make isolating diode a(V2) anode tap be low level, but at this moment not gate b(IC3) output terminal be high level, high level is by isolating diode d(V5) be input to triode a(VT1) base stage and not gate a(IC2) input end, make triode a(VT1) keep conducting, maintain water circulating pump and run, subsequently, temperature in agricultural greenhouse continues to rise, when the temperature in agricultural greenhouse rises to the temperature of setting, the indicator of electric contact thermometer (TK) touches upper limit electrode, high level is by ceiling temperature signal end (4) and isolating diode b(V3) enter into not gate b(IC3) input end, make not gate b(IC3) output terminal be reversed to low level, triode a(VT1) cut-off, first relay coil (K1) power-off, first relay normally open contact (K3) is discharged disconnect, water circulating pump stops, at this moment, not gate a(IC2) input end be low level, make not gate a(IC2) output terminal be reversed to high level, high level is by isolating diode c(V4) enter into not gate b(IC3) input end, when the temperature in agricultural greenhouse declines a little and makes the indicator electrode of electric contact thermometer (TK) leave upper limit electrode, not gate b(IC3) output terminal be still low level, maintain water circulating pump halted state, until the temperature in agricultural greenhouse drops to the lower limit temperature of setting, water circulating pump is starting operation again.
In the specific implementation, the voltage of DC supply (V+) is 12V in the present invention, divider resistance a(R4 in open-phase protection circuit) and divider resistance b(R5) between form dividing point, by determining divider resistance a(R4) and divider resistance b(R5) resistance, make partial pressure value be 2%, sampling diode (V13) selects breakdown reverse voltage to be the voltage stabilizing diode of 7.5V, when water circulating pump works, the phase line test side a(6 of control circuit), phase line test side b(7) and phase line test side c(8) carry out voltage sampling from three input ends of water circulating pump motor winding, then sampling voltage is sent into by commutation diode a(V7), commutation diode b(V8), commutation diode c(V9), commutation diode d(V10), commutation diode e(V11) and commutation diode f(V12) three-phase bridge rectifier circuit that forms, the phase voltage of three-phase supply is 220V, line voltage is 380V, when voltage on three input ends of water circulating pump motor winding is normal, the output voltage of three-phase bridge rectifier circuit is 2.34 × 220=514.8V, after dividing potential drop, the voltage being input to sampling diode (V13) negative electrode is 10V, be greater than the breakdown reverse voltage of sampling diode (V13), just have electric current to enter triode b(VT2) base stage, make triode b(VT2) conducting, not gate c(IC4) input end be low level, cause not gate d(IC5) output terminal be low level, triode c(VT3) cut-off, second relay is failure to actuate, the normally closed contact (K5) of the second relay remains closed, water circulating pump normally runs.When lacking any phase voltage on three input ends of water circulating pump motor winding, three-phase bridge rectifier circuit just presses the work pattern of single phase bridge type rectifier circu, the output voltage of rectification circuit is 0.9 × 380=342V, after dividing potential drop, the voltage being input to sampling diode (V13) negative electrode is 6.84V, be less than the breakdown reverse voltage of sampling diode (V13), do not have electric current to enter triode b(VT2) base stage, triode b(VT2) cut-off, not gate c(IC4) input end be high level, cause not gate d(IC5) output terminal be high level, triode c(VT3) conducting, coil (K4) energising of the second relay, the normally closed contact (K5) of the second relay disconnects, water circulating pump stops, carry out open-phase protection.When carrying out open-phase protection, the second relay normally open contact (K6) adhesive, pilot lamp diode (V1) is lighted and is sent chimes of doom with buzzer (Y).
In above-mentioned invention; consider that the actuation time of contactor has delayed; in order to prevent protection by mistake; at not gate c(IC4) input end delay capacitor (C3) is set; coordinating time delay resistance (R7), make not gate c(IC4) high level of input end is greater than the retardation time of contactor action retardation time, avoids error protection action; delay capacitor (C3) also has Anti-Jamming, makes circuit working more reliable.Utilize the normally closed contact of the first relay (K2) that the positive pole of delay capacitor (C3) is shorted to ground wire when water circulating pump normally stops, making the charging of delay capacitor (C3) from during water circulating pump starting operation.
In above-mentioned invention, utilize three-phase bridge rectifier circuit to detect three input terminal voltages of motor winding, to obtain the normal voltage data different with phase shortage voltage, sampling method is simple, and facilitate late-class circuit process, sampling spot is arranged on three input ends of motor winding, makes to detect correctly reliable, avoid occurring because of the phase shortage accident that the contact of contactor main contacts is bad or electrothermal relay fault causes.
In above-mentioned invention, use cheap diode and cheap not gate digital integrated circuit to come operation or the stopping of process information and controlled circulation water pump, have the advantages that circuit structure is simple and cost is low.During concrete enforcement, not gate digital integrated circuit selects model to be the cmos digital integrated circuit of CC4069 or CC40106 hex inverter, two groups of unnecessary not gates are parallel to not gate d(IC5) on, cmos digital integrated circuit has reliable operation and non-damageable feature.
The invention has the beneficial effects as follows: the control circuit of a kind of geothermal utilization provided; be adapted at applying in agricultural greenhouse, floriculture greenhouse or textile manufacturing workshop; automatically run by the lower limit temperature set or ceiling temperature or stop; there is default-phase protection function; terrestrial heat utilization system is rationally run; for the environment of favourable production is built in agricultural greenhouse, floriculture greenhouse or textile manufacturing workshop, save manpower and avoid waste of energy.The present invention uses cheap diode and cheap not gate digital integrated circuit to carry out process information, makes circuit have the advantages that structure is simple and cost is low.
Accompanying drawing explanation
Accompanying drawing is the control circuit figure of a kind of geothermal utilization of the present invention.
In figure: R1. current-limiting resistance, R2. road resistance is close to, R3. resistance a is driven, R4. divider resistance a, R5. divider resistance b, R6. biasing resistor, R7. time delay resistance, R8. resistance b is driven, C1. filter capacitor a, C2. filter capacitor b, C3. delay capacitor, VD. single phase bridge type rectifier circu, V1. pilot lamp diode, V2. isolating diode a, V3. isolating diode b, V4. isolating diode c, V5. isolating diode d, V6. clamp diode a, V7. commutation diode a, V8. commutation diode b, V9. commutation diode c, V10. commutation diode d, V11. commutation diode e, V12. commutation diode f, V13. diode is sampled, V14. clamp diode b, VT1. triode a, VT2. triode b, VT3. triode c, V+. DC supply, IC1. integrated package of pressure-stabilizing, IC2. not gate a, IC3. not gate b, IC4. not gate c, IC5. not gate d, TC. rectifier transformer, K1. the first relay coil, K2. the first relay normally closed contact, K3. the first relay normally open contact, K4. the second relay coil, K5. the second relay normally closed contact, K6. the second relay normally open contact, Y. buzzer, TK. electric contact thermometer, QS. automatic cut-off switch, FU1. fuse, FU2. fuse, KM. the coil of contactor, KM-K. the main contacts switch of contactor, FR. electrothermal relay, FR-K. the switch of electrothermal relay, N. the zero line of power supply, L1. the phase line a of power supply, L2. the phase line b of power supply, L3. the phase line c of power supply, U. wire a, V. wire b, W. wire c, M. the threephase motor of water pump, 1. the zero line input end of power supply, 2. the phase line input end of power supply, 3. lower limit temperature signal end, 4. ceiling temperature signal end, 5. feed end, 6. phase line test side a, 7. phase line test side b, 8. phase line test side c, 9. control end a, 10. control end b.
Embodiment
embodimentin embodiment shown in the drawings, a kind of control circuit of geothermal utilization is by power circuit, information-processing circuit, control output circuit composition and open-phase protection circuit composition, power circuit is by rectifier transformer (TC), the zero line input end (1) of power supply, the phase line input end (2) of power supply, single phase bridge type rectifier circu (VD), filter capacitor a(C1), integrated package of pressure-stabilizing (IC1) and filter capacitor b(C2) form, the primary coil of rectifier transformer (TC) is connected to the phase line input end (2) of power supply and the zero line input end (1) of power supply, the secondary coil of rectifier transformer (TC) is connected to two input ends of single phase bridge type rectifier circu (VD), the positive pole of single phase bridge type rectifier circu (VD) is connected to filter capacitor a(C1) positive pole and the input end of integrated package of pressure-stabilizing (IC1), output terminal and the filter capacitor b(C2 of integrated package of pressure-stabilizing (IC1)) positive pole be connected after form DC supply (V+), the negative pole of single phase bridge type rectifier circu (VD), filter capacitor a(C1) negative pole, filter capacitor b(C2) negative pole be connected with the earth terminal of integrated package of pressure-stabilizing (IC1) after form ground wire, information-processing circuit is by feed end (5), lower limit temperature signal end (3), ceiling temperature signal end (4), not gate a(IC2), not gate b(IC3), isolating diode a(V2), isolating diode b(V3), isolating diode c(V4) and isolating diode d(V5) form, feed end (5) is connected to DC supply (V+), lower limit temperature signal end (3) is connected to isolating diode a(V2) anode, ceiling temperature signal end (4) is connected to isolating diode b(V3) anode, isolating diode b(V3) negative electrode be connected to not gate b(IC3) input end, at not gate b(IC3) input end and ground wire between You Bang road resistance (R2), not gate b(IC3) output terminal be connected to isolating diode d(V5) anode, isolating diode d(V5) negative electrode and isolating diode a(V2) negative electrode be connected to not gate a(IC2) input end, not gate a(IC2) output terminal be connected to isolating diode c(V4) anode, isolating diode c(V4) negative electrode be connected to not gate b(IC3) input end, control output circuit by driving resistance a(R3), triode a(VT1), clamp diode a(V6), first relay, control end a(9) and control end b(10) form, first relay comprises coil (K1), normally opened contact (K3) and normally closed contact (K2), drive resistance a(R3) the first pin be connected to isolating diode a(V2) negative electrode and isolating diode d(V5) negative electrode, drive resistance a(R3) crus secunda be connected to triode a(VT1) base stage, triode a(VT1) emitter be connected to ground wire, triode a(VT1) collector be connected to clamp diode a(V6) anode and the second end of the first relay coil (K1), clamp diode a(V6) negative electrode and the first end of the first relay coil (K1) be connected to DC supply (V+), the first end of the first relay normally open contact (K3) is connected to control end a(9), second end of the first relay normally open contact (K3) is connected to control end b(10 by the normally closed contact (K5) of the second relay), open-phase protection circuit is by phase line test side a(6), phase line test side b(7), phase line test side c(8), commutation diode a(V7), commutation diode b(V8), commutation diode c(V9), commutation diode d(V10), commutation diode e(V11), commutation diode f(V12), divider resistance a(R4), divider resistance b(R5), sampling diode (V13), biasing resistor (R6), triode b(VT2), time delay resistance (R7), not gate c(IC4), not gate d(IC5), drive resistance b(R8), triode c(VT3), clamp diode b(V14) and the second relay, current-limiting resistance (R1), pilot lamp diode (V1) and buzzer (Y) are formed, second relay comprises coil (K4), normally closed contact (K5) and normally opened contact (K6), by commutation diode a(V7), commutation diode b(V8), commutation diode c(V9), commutation diode d(V10), commutation diode e(V11) and commutation diode f(V12) form three-phase bridge rectifier circuit, phase line test side a(6) be connected to commutation diode a(V7) anode and commutation diode b(V8) negative electrode, phase line test side b(7) be connected to commutation diode c(V9) anode and commutation diode d(V10) negative electrode, phase line test side c(8) be connected to commutation diode e(V11) anode and commutation diode f(V12) negative electrode, commutation diode b(V8) anode, commutation diode d(V10) anode and commutation diode f(V12) anode be connected to ground wire, commutation diode a(V7) negative electrode, commutation diode c(V9) negative electrode and commutation diode e(V11) negative electrode be connected to divider resistance a(R4) the first pin, divider resistance a(R4) crus secunda be connected to divider resistance b(R5) the first pin and sampling diode (V13) negative electrode, divider resistance b(R5) crus secunda be connected to ground wire, the anode of sampling diode (V13) is connected to triode b(VT2 by biasing resistor (R6)) base stage, first pin of time delay resistance (R7) is connected to DC supply (V+), the crus secunda of time delay resistance (R7) is connected to triode b(VT2) collector, the positive pole of delay capacitor (C3), not gate c(IC4) input end and the first end of the first relay normally closed contact (K2), triode b(VT2) emitter, the negative pole of delay capacitor (C3) and the second end of the first relay normally closed contact (K2) are connected to ground wire, not gate c(IC4) output terminal be connected to not gate d(IC5) input end, not gate d(IC5) output terminal be connected to drive resistance b(R8) the first pin, drive resistance b(R8) crus secunda be connected to triode c(VT3) base stage, triode c(VT3) emitter be connected to ground wire, triode c(VT3) collector be connected to clamp diode b(V14) anode and the second end of the second relay coil (K4), clamp diode b(V14) negative electrode and the first end of the second relay coil (K4) be connected to DC supply (V+), the first end of the second relay normally closed contact (K5) is connected to the second end of the first relay normally open contact (K3), second end of the second relay normally closed contact (K5) is connected to control end b(10), first pin of current-limiting resistance (R1) and the input end of buzzer (Y) are connected to DC supply (V+), current-limiting resistance (R1) crus secunda is connected to the anode of pilot lamp diode (V1), the negative electrode of pilot lamp diode (V1) and the output terminal of buzzer (Y) are connected to the first end of the second relay normally open contact (K6), second end of the second relay normally open contact (K6) is connected to ground wire.
In the present embodiment, not gate a(IC2), not gate b(IC3), not gate c(IC4), not gate d(IC5) share a not gate digital integrated circuit, not gate digital integrated circuit selects model to be the cmos digital integrated circuit of CC4069 or CC40106 hex inverter, two groups of unnecessary not gates are parallel to not gate d(IC5) on, the power end of digital integrated circuit is connected to DC supply (V+), and the earth terminal of digital integrated circuit is connected to ground wire, the voltage of DC supply (V+) is 12V, divider resistance a(R4) resistance be 500K Ω, divider resistance b(R5) resistance be 10K Ω, make the divider resistance a(R4 in open-phase protection circuit) and divider resistance b(R5) between the partial pressure value of voltage be 2%, sampling diode (V13) selects breakdown reverse voltage to be the voltage stabilizing diode of 7.5V, the outer of control circuit is with electric contact thermometer (TK), contactor, electrothermal relay (FR), three-phase and four-line supply line and water circulating pump, the indicator Electrode connection of electric contact thermometer (TK) is to feed end (5), the lower limit Electrode connection of electric contact thermometer (TK) is to lower limit temperature signal end (3), and the upper limit Electrode connection of electric contact thermometer (TK) is to ceiling temperature signal end (4), contactor comprises coil (KM) and three groups of main contacts switches, three-phase and four-line supply line comprises wire a(U), wire b(V), wire c(W) and zero line (N), the zero line input end (1) of control circuit is connected on the zero line (N) of supply line, the phase line input end (2) of control circuit is connected to wire a(U) on, the first end of contactor coil (KM) is connected to wire c(W) on, second end of contactor coil (KM) is connected on the switch first end of electrothermal relay (FR), switch second end of electrothermal relay (FR) is connected to the control end a(9 of control circuit), the control end b(10 of control circuit) be connected to wire b(V) on, the phase line test side a(6 of control circuit), phase line test side b(7) and phase line test side c(8) be connected respectively on the three phase electric machine terminals of water circulating pump, the upper end of three groups of main contacts switches of contactor is connected respectively to wire a(U), wire b(V) and wire c(W) on, the lower end of three groups of main contacts switches of contactor is connected on the three phase electric machine terminals of water circulating pump by the leading body of electrothermal relay (FR).
During the present embodiment application, wire a(U), wire b(V) and wire c(W) be connected to the phase line a(L1 of power supply by QS. automatic cut-off switch), the phase line b(L2 of power supply) and the phase line c(L3 of power supply) on, the temperature-sensitive bag of electric contact thermometer (TK) is arranged in agricultural greenhouse, indicator electrode, lower limit electrode and upper limit electrode is had in electric contact thermometer (TK), in the winter time, the lower limit temperature of electric contact thermometer (TK) is arranged between 12 °-15 °, the ceiling temperature of electric contact thermometer (TK) is arranged between 18 °-20 °; In summer, the lower limit electrode of electric contact thermometer (TK) is changed into and is connected to ceiling temperature signal end (4), the upper limit electrode of electric contact thermometer (TK) changes into and is connected to lower limit temperature signal end (3), the lower limit temperature of electric contact thermometer (TK) is arranged on 25 °, the ceiling temperature of electric contact thermometer (TK) is arranged on 28 °.For the thermostatic control in winter of agricultural greenhouse, during work, when temperature in agricultural greenhouse drops to the lower limit temperature of setting, the indicator of electric contact thermometer (TK) touches lower limit electrode, high level is by lower limit temperature signal end (3) and isolating diode a(V2) enter into triode a(VT1) base stage and not gate a(IC2) input end, make triode a(VT1) conducting and make not gate a(IC2) output terminal be low level, make not gate b(IC3) input end be low level, not gate b(IC3) output terminal be high level, triode a(VT1) after conducting, first relay coil (K1) is energized, first relay normally open contact (K3) adhesive is energized, start cycles water pump operation, pumping underground hot water is heated to agricultural greenhouse by heating radiator in a looping fashion, temperature in agricultural greenhouse raises along with the operation of water circulating pump, the indicator electrode of electric contact thermometer (TK) leaves lower limit electrode, make isolating diode a(V2) anode tap be low level, but at this moment not gate b(IC3) output terminal be high level, high level is by isolating diode d(V5) be input to triode a(VT1) base stage and not gate a(IC2) input end, make triode a(VT1) keep conducting, maintain water circulating pump and run, subsequently, temperature in agricultural greenhouse continues to rise, when the temperature in agricultural greenhouse rises to the temperature of setting, the indicator of electric contact thermometer (TK) touches upper limit electrode, high level is by ceiling temperature signal end (4) and isolating diode b(V3) enter into not gate b(IC3) input end, make not gate b(IC3) output terminal be reversed to low level, triode a(VT1) cut-off, first relay coil (K1) power-off, first relay normally open contact (K3) is discharged disconnect, water circulating pump stops, at this moment, not gate a(IC2) input end be low level, make not gate a(IC2) output terminal be reversed to high level, high level is by isolating diode c(V4) enter into not gate b(IC3) input end, when the temperature in agricultural greenhouse declines a little and makes the indicator electrode of electric contact thermometer (TK) leave upper limit electrode, not gate b(IC3) output terminal be still low level, maintain water circulating pump halted state, until the temperature in agricultural greenhouse drops to the lower limit temperature of setting, water circulating pump again can starting operation.
The present embodiment is when water circulating pump works, the phase line test side a(6 of control circuit), phase line test side b(7) and phase line test side c(8) carry out voltage sampling from three input ends of water circulating pump motor winding, then sampling voltage is sent into by commutation diode a(V7), commutation diode b(V8), commutation diode c(V9), commutation diode d(V10), commutation diode e(V11) and commutation diode f(V12) three-phase bridge rectifier circuit that forms, the phase voltage of three-phase supply is 220V, line voltage is 380V, when voltage on three input ends of water circulating pump motor winding is normal, the output voltage of three-phase bridge rectifier circuit is 2.34 × 220=514.8V, after dividing potential drop, the voltage being input to sampling diode (V13) negative electrode is 10V, be greater than the breakdown reverse voltage of sampling diode (V13), just have electric current to enter triode b(VT2) base stage, make triode b(VT2) conducting, not gate c(IC4) input end be low level, cause not gate d(IC5) output terminal be low level, triode c(VT3) cut-off, second relay is failure to actuate, the normally closed contact (K5) of the second relay remains closed, water circulating pump normally runs.When lacking any phase voltage on three input ends of water circulating pump motor winding, three-phase bridge rectifier circuit just presses the work pattern of single phase bridge type rectifier circu, the output voltage of rectification circuit is 0.9 × 380=342V, after dividing potential drop, the voltage being input to sampling diode (V13) negative electrode is 6.84V, be less than the breakdown reverse voltage of sampling diode (V13), do not have electric current to enter triode b(VT2) base stage, triode b(VT2) cut-off, not gate c(IC4) input end be high level, cause not gate d(IC5) output terminal be high level, triode c(VT3) conducting, coil (K4) energising of the second relay, the normally closed contact (K5) of the second relay disconnects, water circulating pump stops, carry out open-phase protection.When carrying out open-phase protection, the second relay normally open contact (K6) adhesive, pilot lamp diode (V1) is lighted and is sent chimes of doom with buzzer (Y).