CN215601216U - Control circuit of low-voltage frequency converter - Google Patents
Control circuit of low-voltage frequency converter Download PDFInfo
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- CN215601216U CN215601216U CN202121200961.9U CN202121200961U CN215601216U CN 215601216 U CN215601216 U CN 215601216U CN 202121200961 U CN202121200961 U CN 202121200961U CN 215601216 U CN215601216 U CN 215601216U
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Abstract
The application discloses control circuit of low-voltage inverter includes: the starting and stopping control circuit, the main contactor and the delay switch circuit; the delay switch circuit is connected with the start-stop control circuit, a coil and a normally open auxiliary contact of the main contactor and the low-voltage frequency converter, and the normally open main contact of the main contactor is connected between the low-voltage frequency converter and the three-phase alternating current; the start-stop control circuit is used for controlling the time delay switch circuit to be powered on or powered off; the time delay switch circuit is used for controlling the coil of the main contactor to be electrified when the coil of the main contactor is electrified and triggering the low-voltage frequency converter to start to operate after a first preset time after the coil of the main contactor is controlled to be electrified; when the power is lost, the low-voltage frequency converter is triggered to stop running, and after the second preset time after the low-voltage frequency converter is triggered to stop running, the coil of the main contactor is controlled to lose power. The control circuit can not only realize that the starting and stopping of the main contactor and the frequency converter can be controlled by giving the starting and stopping signals all the way, but also ensure the safety and the reliable operation of the frequency converter.
Description
Technical Field
The application relates to the technical field of frequency converter control, in particular to a control circuit of a low-voltage frequency converter.
Background
The low-voltage frequency converter is widely applied to various fields, such as metallurgy, chemical engineering, papermaking, machinery and the like. The primary main loop element of the low-voltage frequency converter mainly comprises a protection element and a control element. In general, incoming line isolation repair tools and circuit breaker protection switches on the input side of the frequency converter are configured consistently, and filters and alternating current reactors on the input side or the output side of the frequency converter are configured correspondingly according to the condition of a field power grid and the condition of a motor. For the control elements in the primary main loop, the frequency converter manufacturer recommends, for safety reasons, the addition of a main contactor between the power supply and the input of the frequency converter. The main contactor is additionally arranged on the input side, so that the power supply can be protected and the fault expansion can be prevented, when the system has a fault, the main contactor is disconnected, and the input power supply of the frequency converter can be effectively cut off, so that the safety is ensured. But does not allow the use of the main contactor to control the start and stop of the frequency converter. Therefore, in a low-voltage frequency converter control loop with a main contactor on the input side, the main contactor needs to be closed firstly, then the main loop of the frequency converter is electrified, and the frequency converter is started after self-checking is completed. When the frequency converter is stopped, and when the frequency converter has no output and the loop is not frequently started, the main contactor is disconnected.
If the main contactor and the frequency converter are independently and respectively started and stopped, more control loops, more fault points and complicated operation are caused, and errors are easy to occur. Therefore, providing a control circuit that can realize start-stop control of the main contactor and the frequency converter by giving a single path of start-stop signal and ensure safety and reliable operation of the frequency converter has become a technical problem to be solved by those skilled in the art.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing a control circuit of low-voltage inverter, the setting is stopped the signal and just can be realized opening the control of opening to opening of main contactor and converter all the way, ensures converter safety and reliable operation.
In order to solve the above technical problem, the present application provides a control circuit of a low voltage frequency converter, including:
the starting and stopping control circuit, the main contactor and the delay switch circuit; the time delay switch circuit is respectively connected with the start-stop control circuit, the coil of the main contactor, the normally open auxiliary contact of the main contactor and the low-voltage frequency converter, and the normally open main contact of the main contactor is connected between the low-voltage frequency converter and the three-phase alternating current;
the start-stop control circuit is used for controlling the time delay switch circuit to be powered on or powered off;
the time delay switch circuit is used for controlling the coil of the main contactor to be electrified when the time delay switch circuit is electrified, and triggering the low-voltage frequency converter to start operation after a first preset time after the coil of the main contactor is controlled to be electrified; when the time delay switch circuit loses power, the low-voltage frequency converter is triggered to stop running, and after the low-voltage frequency converter is triggered to stop running for a second preset time, the coil of the main contactor is controlled to lose power.
Optionally, the delay switch circuit includes:
the circuit comprises an intermediate switch circuit, a first delay switch circuit and a second delay switch circuit; the intermediate switch circuit is respectively connected with the start-stop control circuit and the first delay switch circuit, the first delay switch circuit is also connected with a normally-open auxiliary contact of the main contactor and the low-voltage frequency converter, and the second delay switch circuit is respectively connected with the start-stop control circuit and a coil of the main contactor;
the intermediate switch circuit is used for controlling the first time delay switch circuit to be powered on or powered off;
the second time delay switch circuit is used for controlling the coil of the main contactor to be immediately powered on when the second time delay switch circuit is powered on, and controlling the coil of the main contactor to be powered off after delaying the second preset time when the second time delay switch circuit is powered off;
the first time delay switch circuit is used for triggering the low-voltage frequency converter to start and operate after the first preset time when the first time delay switch circuit is electrified, and immediately triggering the low-voltage frequency converter to stop operating when the first time delay switch circuit is electrified.
Optionally, the intermediate switching circuit includes:
a first intermediate relay; the coil of the first intermediate relay is connected in series with the start-stop control circuit and then is connected between the live wire and the zero line; and the normally open auxiliary contact of the first intermediate relay is connected with the first time delay switch circuit.
Optionally, the first delay switch circuit includes:
a power-on time delay relay;
after being connected in series with the normally open auxiliary contact of the first intermediate relay and the normally open auxiliary contact of the main contactor, the coil of the power-on time delay relay is connected between the live wire and the zero line; and a normally open auxiliary contact of the power-on time delay relay is connected between a start-stop control terminal and a power supply terminal of the low-voltage frequency converter.
Optionally, the second delay switch circuit includes:
a power-off delay relay;
a coil of the power-off delay relay is connected in series with the start-stop control circuit and then is connected between the live wire and the zero line; and a normally open auxiliary contact of the power-off delay relay is connected in series with a coil of the main contactor and then is connected between the live wire and the zero line.
Optionally, the start-stop control circuit includes a first start button, a second start button, a first stop button, a second stop button, a third gear selector switch, and a remote control switch;
the first starting button and the first stopping button are connected in series and then connected with a first gear of the three-gear selector switch; the second starting button and the second stopping button are connected in series and then connected with a second gear of the three-gear selector switch; the remote control switch is connected with a third gear of the three-gear selector switch; the first starting button and the second starting button are connected with the normally open auxiliary contact of the first intermediate relay in parallel.
Optionally, the method further includes:
the cabinet contactor runs the pilot lamp; the cabinet contactor operation indicator lamp is connected in series with the normally open auxiliary contact of the main contactor and then connected between the live wire and the zero line.
Optionally, the method further includes:
the second intermediate relay and the frequency conversion operation indicator lamp of the cabinet; a coil of the second intermediate relay is connected in series with an operating contact of the low-voltage frequency converter and then connected between the live wire and the zero line, and a normally open auxiliary contact of the second intermediate relay is connected in series with the cabinet variable-frequency operating indicator lamp and then connected between the live wire and the zero line;
the third intermediate relay and the frequency conversion fault indicator lamp of the cabinet; third auxiliary relay's coil with connect after the trouble contact of low-voltage inverter establishes ties the live wire with between the zero line, third auxiliary relay's normally closed auxiliary contact with first auxiliary relay's coil and open stop after the control circuit establishes ties connect in the live wire with between the zero line, third auxiliary relay's normally open auxiliary contact with connect after this cabinet frequency conversion fault indication lamp establishes ties in the live wire with between the zero line.
Optionally, the normally open auxiliary contact of the second intermediate relay and the normally open auxiliary contact of the third intermediate relay are further connected to a remote control terminal.
Optionally, the method further includes:
the on-site contactor comprises an on-site contactor operation indicator lamp, an on-site frequency conversion operation indicator lamp and an on-site frequency conversion fault indicator lamp;
the on-site contactor operation indicator lamp is connected with the local contactor operation indicator lamp in parallel; the local variable frequency operation indicator lamp is connected with the local variable frequency operation indicator lamp in parallel; the local frequency conversion fault indicator lamp is connected with the local frequency conversion fault indicator lamp in parallel.
The application provides a control circuit of low-voltage inverter includes: the starting and stopping control circuit, the main contactor and the delay switch circuit; the time delay switch circuit is respectively connected with the start-stop control circuit, the coil of the main contactor, the normally open auxiliary contact of the main contactor and the low-voltage frequency converter, and the normally open main contact of the main contactor is connected between the low-voltage frequency converter and the three-phase alternating current; the start-stop control circuit is used for controlling the time delay switch circuit to be powered on or powered off; the time delay switch circuit is used for controlling the coil of the main contactor to be electrified when the time delay switch circuit is electrified, and triggering the low-voltage frequency converter to start operation after a first preset time after the coil of the main contactor is controlled to be electrified; when the time delay switch circuit loses power, the low-voltage frequency converter is triggered to stop running, and after the low-voltage frequency converter is triggered to stop running for a second preset time, the coil of the main contactor is controlled to lose power.
It is thus clear that the control circuit that this application provided, with the help of delay switch circuit's time delay function, when starting the low-voltage inverter operation, open through all the way open stop signal alright with realize that main contactor is closed earlier, main contactor is closed the back, the electricity self-checking on the low-voltage inverter to after a period, the low-voltage inverter starts the operation. When the low-voltage frequency converter stops running, the low-voltage frequency converter can be shut down firstly through one path of start-stop signals, and the main contactor is disconnected again after a period of time. The control circuit can realize that the starting and stopping of the main contactor and the frequency converter can be controlled by giving the starting and stopping signals all the way, can ensure the safety and the reliable operation of the frequency converter, and has simple circuit and fewer circuits. In addition, when the internal resistor of the frequency converter is overheated, the chopper breaks down or the starting control circuit is turned off, the coil of the main contactor loses power, the normally open main contact of the main contactor is disconnected, and the low-voltage frequency converter is powered off once. For the frequency converter loop which is not frequently started, when the starting control circuit is turned off, the main contact of the main contactor is disconnected, the frequency converter is not electrified once, the energy consumption can be reduced, and the energy is saved.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the prior art and the embodiments are briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
Fig. 1 is a schematic diagram of a control circuit of a low voltage inverter according to an embodiment of the present disclosure;
fig. 2 is a schematic diagram of a first part of a control circuit of a low-voltage inverter according to an embodiment of the present application;
fig. 3 is a schematic diagram of a second part of a control circuit of a low-voltage inverter according to an embodiment of the present application;
fig. 4 is a schematic diagram of a third part of a control circuit of a low-voltage inverter according to an embodiment of the present application.
Detailed Description
The core of this application is to provide a control circuit of low-voltage inverter, gives all the way and opens the start-stop signal and just can realize opening the start-stop control to main contactor and converter, ensures converter safety and reliable operation.
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Referring to fig. 1, fig. 1 is a schematic diagram of a control circuit of a low voltage inverter according to an embodiment of the present application, and referring to fig. 1, the control circuit mainly includes:
the system comprises a start-stop control circuit 10, a main contactor 20 and a delay switch circuit 30; the delay switch circuit 30 is respectively connected with the start-stop control circuit 10, the coil of the main contactor 20, the normally open auxiliary contact of the main contactor 20 and the low-voltage frequency converter, and the normally open main contact of the main contactor 20 is connected between the low-voltage frequency converter and the three-phase alternating current;
the start-stop control circuit 10 is used for controlling the delay switch circuit 30 to be powered on or powered off;
the delay switch circuit 30 is used for controlling the coil of the main contactor 20 to be electrified when the delay switch circuit 30 is electrified, and triggering the low-voltage frequency converter to start running after a first preset time after the coil of the main contactor 20 is controlled to be electrified; when the time delay switch circuit 30 loses power, the low-voltage frequency converter is triggered to stop running, and after a second preset time after the low-voltage frequency converter is triggered to stop running, the coil of the main contactor 20 is controlled to lose power.
The delay switch circuit 30 may include:
the circuit comprises an intermediate switch circuit, a first delay switch circuit and a second delay switch circuit; the intermediate switch circuit is respectively connected with the start-stop control circuit and the first delay switch circuit, the first delay switch circuit is also connected with a normally open auxiliary contact of the main contactor and the low-voltage frequency converter, and the second delay switch circuit is respectively connected with the start-stop control circuit and a coil of the main contactor;
the intermediate switch circuit is used for controlling the first time delay switch circuit to be powered on or powered off;
the second time delay switch circuit is used for controlling the coil of the main contactor to be immediately electrified when the second time delay switch circuit is electrified, and controlling the coil of the main contactor to be electrified after delaying for second preset time when the second time delay switch circuit is electrified;
the first time delay switch circuit is used for triggering the low-voltage frequency converter to start operation after delaying for first preset time when the first time delay switch circuit is powered on, and immediately triggering the low-voltage frequency converter to stop operation when the first time delay switch circuit is powered off.
Thus, when the low-voltage inverter is started to operate, the operation start-stop control circuit 10 is turned on. After the start-stop control circuit 10 is switched on, the intermediate switch circuit and the second delay switch circuit are powered on, and then after the second delay switch circuit is powered on, the coil KM of the main contactor is powered on immediately. After the coil KM of the main contactor is obtained, the normally open main contact 2KM of the main contactor is closed, and the low-voltage frequency converter is electrified once, so that self-checking can be carried out. After the coil of the main contactor is electrified, the normally open auxiliary contact of the main contactor is closed, and the first delay switch circuit is electrified at the moment because the middle switch circuit is electrified before. And the first time delay switch circuit triggers the low-voltage frequency converter to start operation after obtaining the first preset time. Therefore, when the low-voltage inverter is started, the main contactor is firstly closed, and the low-voltage inverter is started to operate.
When the low-voltage frequency converter stops running, the operation start-stop control circuit 10 is turned off. After the start-stop control circuit 10 is turned off, the intermediate switch circuit is powered off, and further, after the intermediate switch circuit is powered off, the first delay switch circuit is powered off. The first time delay switch circuit triggers the low-voltage frequency converter to stop running immediately after power failure. After the start-stop control circuit 10 is turned off, the second time delay switch circuit also loses power, and then after a second preset time after the second time delay switch circuit loses power, the coil KM of the main contactor loses power, and the low-voltage frequency converter loses power for one time. Therefore, when the low-voltage frequency converter is shut down, the low-voltage frequency converter stops running first and the main contactor is disconnected later.
Referring to fig. 2 to 4, in a specific embodiment, the intermediate switching circuit may include: a first intermediate relay; the first delay switch circuit may include: a power-on time delay relay; the second delay switch circuit may include: a power-off delay relay;
a coil KA1 of the first intermediate relay is connected in series with the start-stop control circuit 10 and then is connected between a live wire and a zero wire; a normally open auxiliary contact 1KA1 of the first intermediate relay is connected in series with a normally open auxiliary contact 1KM of the main contactor and a coil KT1 of the electrified time delay relay and then is connected between a live wire and a zero wire; the normally open auxiliary contact 1KT1 of circular telegram time delay relay connects between the start-stop control terminal and the power supply terminal of low-voltage inverter. A coil KT2 of the power-off delay relay is connected with a coil KA1 of the first intermediate relay in parallel; and a normally open auxiliary contact 1KT2 of the power-off delay relay is connected in series with a coil KM of the main contactor and then is connected between a live wire and a zero wire.
When the low-voltage frequency converter is started to operate, the operation start-stop control circuit 10 is conducted. After the start-stop control circuit 10 is turned on, the coil KA1 of the first intermediate relay is powered. Meanwhile, since the coil KT2 of the power-off delay relay is connected in parallel with the coil KA1 of the first intermediate relay, when the start-stop control circuit 10 is turned on, the coil KT2 of the power-off delay relay is also powered on. The coil KM of main contactor and normally open auxiliary contact 1KT2 of outage time delay relay connect between live wire and zero line after establishing ties, so when opening and stopping control circuit 10 and switch on, the coil KT2 of outage time delay relay gets into the electricity, normally open auxiliary contact 1KT2 of outage time delay relay is closed immediately, and then the coil KM of main contactor gets into the electricity, the normally open main contact 2KM of main contactor is closed, three-phase alternating current and low-voltage inverter switch-on, can carry out the self-checking on the low-voltage inverter. Simultaneously the coil KM of main contactor gets after the electricity, the normally open auxiliary contact 1KM of main contactor also can be closed, the circular telegram time delay relay's coil KT1 who establishes ties with the normally open auxiliary contact 1KM of main contactor and the normally open auxiliary contact 1KA1 of first auxiliary relay gets the electricity, after the time of delay settlement, the normally open auxiliary contact 1 1 of circular telegram time delay relay is closed, with the low-voltage KT frequency converter open the potential of opening the control terminal and draw high, make the low-voltage frequency converter start-up operation.
When the low-voltage frequency converter stops running, the operation start-stop control circuit 10 is turned off. Open and stop control circuit 10 and close the back, first auxiliary relay's coil KA1 loses electricity, and then the normally open auxiliary contact 1KA1 disconnection of first auxiliary relay, and the coil KT1 of circular telegram time delay relay loses electricity, and the normally open auxiliary contact 1KT1 of circular telegram time delay relay breaks off immediately, pulls down the potential of opening of low-voltage inverter and stopping control terminal, makes the low-voltage inverter stop immediately. Meanwhile, after the start-stop control circuit 10 is turned off, the coil KT2 of the power-off delay relay is also powered off, after the coil KT2 of the power-off delay relay is powered off, when the time delay is reached, the normally-open auxiliary contact 1KT2 of the power-off delay relay is disconnected, then the coil KM of the main contactor is powered off, the normally-open main contact 2KM of the main contactor is disconnected, and the low-voltage frequency converter is powered off once.
The normally open main contact 2KM of the main contactor can be connected between a low-voltage frequency converter and three-phase alternating current after being connected with an isolating knife switch and a breaker in series.
Referring to fig. 2 to 4 (in the drawings, 1BP represents a low voltage inverter), in a specific embodiment, the start-stop control circuit 10 includes a first start button SF1, a second start button SF2, a first stop button SS1, a second stop button SS2, a three-gear switch and a remote switch K; the first start button SF1 is connected with the first stop button SS1 in series and then is connected with the first gear of the three-gear selector switch; the second start button SF2 is connected with the second stop button SS2 in series and then is connected with the second gear of the three-gear selector switch; the remote control switch K is connected with a third gear of the three-gear selector switch; the first start button SF1 and the second start button SF2 are connected in parallel with the normally open auxiliary contact 1KA1 of the first intermediate relay.
Specifically, in the present embodiment, the start/stop control circuit 10 is provided with two sets of start buttons, stop buttons, a remote switch K, and a three-gear switch, so as to satisfy three control requirements of local, and remote automatic control. The three gears of the three-gear change-over switch can be local gears, cabinet gears and automatic gears respectively.
When the three-gear selector switch is in the local gear, the inverter is turned on or off by connecting the first start button SF1 and the first stop button SS1 of the local gear, i.e., the first gear. That is, after the first start button SF1 is pressed, the three-position switch, the first start button SF1 and the first stop button SS1 form a passage, and the coil KA1 of the first intermediate relay and the coil KT2 of the power-off delay relay are energized. When the first stop button SS1 is pressed, the first stop button SS1 is turned off, and the coil KA1 of the first intermediate relay and the coil KT2 of the power-off delay relay are powered off.
When the three-gear change-over switch is located at the gear of the cabinet, the frequency converter is started and stopped by a second start button SF2 and a second stop button SS2 which are connected with the gear of the cabinet, namely a second gear. That is, when the second start button SF2 is pressed, the three-position switch, the second start button SF2 and the second stop button SS2 form a passage, and the coil KA1 of the first intermediate relay and the coil KT2 of the power-off delay relay are energized. When the second stop button SS2 is pressed, the three-gear switch, the second start button SS2 and the second stop button SS2 are turned off, and the coil KA1 of the first intermediate relay and the coil KT2 of the power-off delay relay are powered off.
When the three-gear change-over switch is positioned at the automatic gear, the frequency converter is started and stopped by the remote control switch K which is connected with the automatic gear, namely the third gear. When the remote control switch K is controlled to be closed by the operation distance, the three-gear change-over switch and the remote control switch K form a passage, and the coil KA1 of the first intermediate relay and the coil KT2 of the power-off delay relay are powered on. When the remote control switch K is controlled to be switched off by the operation distance, the three-gear change-over switch is switched off from the remote control switch K, and the coil KA1 of the first intermediate relay and the coil KT2 of the power-off delay relay are powered off.
Normally, when the start button is pressed, the start button is closed, and when the start button is released, the start button is restored to an open state, so that the first start button SF1 and the second start button SF2 are connected in parallel with the normally open auxiliary contact 1KA1 of the first intermediate relay in order to ensure that the start-stop control is effective. From this, after pressing the start button and making the start button closed, coil KA1 of first auxiliary relay gets electric, and normally open auxiliary contact 1KA1 of first auxiliary relay is closed, to the start button auto-lock, makes coil KA1 of first auxiliary relay and coil KT2 of outage delay relay continuously get electric, and can not lead to coil KA1 of first auxiliary relay and coil KT2 of outage delay relay to lose the electricity owing to the start button disconnection after loosening the start button.
The first start button SF1 and the first stop button SS1 can be disposed in the button box, and local control of the low voltage inverter can be realized by operating the first start button SF1 and the first stop button SS1 in the button box. In addition, the control circuit may further include: an emergency stop button SBE; the scram button SBE is connected between the live wire and the zero wire after being connected in series with the start-stop control circuit 10 and the coil KA1 of the first intermediate relay. In an emergency, the emergency stop button SBE can be pressed to power down the coil KA1 of the first intermediate relay and the coil KT2 of the power-off delay relay, thereby emergently stopping the low-voltage inverter. The emergency stop button SBE may also be provided in the button box.
Further, in a specific embodiment, the control circuit further includes:
the cabinet contactor runs the pilot lamp HW 1; the cabinet contactor operation indicator light HW1 is connected between the live wire and the zero wire after being connected in series with the normally open auxiliary contact 1KM of the main contactor.
When the coil KM of the main contactor is electrified, the normally open auxiliary contact 1KM of the main contactor is closed, and the HW1 is lightened by the operation indicator lamp of the contactor of the cabinet. On the contrary, when the coil KM of the main contactor loses power, the normally open auxiliary contact 1KM of the main contactor is disconnected, and the operation indicator lamp HW1 of the cabinet contactor is turned off.
Further, in a specific embodiment, the control circuit further includes:
the second intermediate relay and the frequency conversion operation indicator lamp HR1 of the cabinet; a coil KA2 of the second intermediate relay is connected between the live wire and the zero wire after being connected in series with an operation contact BP1 of the low-voltage frequency converter, and a normally-open auxiliary contact 1KA2 of the second intermediate relay is connected between the live wire and the zero wire after being connected in series with a frequency conversion operation indicator lamp HR1 of the cabinet.
From this, after the low-voltage inverter started the operation, the operation contact BP1 of low-voltage inverter was closed, and then the coil KA2 of second auxiliary relay gets electric, and normally open auxiliary contact 1KA2 of second auxiliary relay is closed, and this cabinet frequency conversion operation pilot lamp HR1 is bright. After the low-voltage inverter stopped operating, the operating contact BP1 disconnection of low-voltage inverter, and then the coil KA2 of second auxiliary relay loses the electricity, and normally open auxiliary contact 1KA2 disconnection of second auxiliary relay, this cabinet frequency conversion operation pilot lamp HR1 goes out.
The normally open auxiliary contact 1KA2 of the second intermediate relay can be further connected with a remote control terminal, when the low-voltage frequency converter starts to operate, a coil KA2 of the second intermediate relay is electrified, the normally open auxiliary contact 1KA2 of the second intermediate relay is closed, and a signal of operation of the frequency converter is fed back to the remote control terminal.
In addition, the control circuit further includes:
the third intermediate relay and the frequency conversion fault indicator lamp HY1 of the cabinet; the coil KA3 of third auxiliary relay and the trouble contact BP2 of low-voltage inverter are connected between live wire and the zero line after establishing ties, and the normally closed auxiliary contact of third auxiliary relay and the coil KA1 of first auxiliary relay and open and stop control circuit 10 and connect between live wire and zero line after establishing ties, and the normally open auxiliary contact 1KA3 of third intermediate relay connects between live wire and zero line after establishing ties with this cabinet frequency conversion trouble pilot lamp HY 1.
From this, when the low-voltage inverter broke down at the operation in-process, the trouble contact BP2 of low-voltage inverter was closed, and then the coil KA3 of third auxiliary relay gets electric, and normally open auxiliary contact 1KA3 of third auxiliary relay is closed, and this cabinet frequency conversion fault indication lamp HY1 is bright, and normally closed auxiliary contact 2KA3 of third auxiliary relay breaks off simultaneously, makes first auxiliary relay's coil KA1 and outage delay relay's coil KT2 lose electricity.
The normally open auxiliary contact 1KA3 of the third intermediate relay can be also connected with a remote control terminal. When the low-voltage frequency converter has a fault, the coil KA3 of the third intermediate relay is electrified, the normally open auxiliary contact 1KA3 of the third intermediate relay is closed, and a signal of the fault of the frequency converter is fed back to the remote control terminal.
Further, in a specific embodiment, the control circuit further includes:
the system comprises a local contactor operation indicator lamp HW2, a local frequency conversion operation indicator lamp HR2 and a local frequency conversion fault indicator lamp HY 2;
the on-site contactor operation indicator light HW2 is connected in parallel with the cabinet contactor operation indicator light HW 1; the local variable frequency operation indicator light HR2 is connected in parallel with the variable frequency operation indicator light HR1 of the cabinet; the local frequency conversion fault indicator lamp HY2 is connected in parallel with the frequency conversion fault indicator lamp HY1 of the cabinet.
Therefore, when the coil KM of the main contactor is electrified, the normally open auxiliary contact 1KM of the main contactor is closed, and the local contactor operation indicator lamp HW2 is lightened. When the low-voltage frequency converter operates, the coil KA2 of the second intermediate relay is electrified, the normally open auxiliary contact 1KA2 of the second intermediate relay is closed, and the local frequency conversion operation indicator lamp HR2 is lightened. When the low-voltage frequency converter has a fault, the coil KA3 of the third intermediate relay is electrified, the normally open auxiliary contact 1KA3 of the third intermediate relay is closed, and the local frequency conversion fault indicator lamp HY2 is on.
The on-site contactor operation indicator lamp, the on-site frequency conversion operation indicator lamp and the on-site frequency conversion fault indicator lamp can be arranged in the button box. Therefore, the states of the main contactor and the low-voltage frequency converter can be known by looking at the on-off states of all the indicating lamps in the button box.
In addition, the control circuit may be further provided with a reset button SB connected between the reset terminal of the low voltage inverter and the power supply terminal. After the reset button SB is pressed, the reset terminal of the low-voltage frequency converter is pulled high, and the low-voltage frequency converter is triggered to reset. In addition, the control circuit can also be provided with a potentiometer 1RP, and the frequency of the low-voltage frequency converter can be set by adjusting the size of the potentiometer 1RP before or in the running process of the low-voltage frequency converter.
To sum up, the control circuit that this application provided, with the help of the time delay function of time delay switch circuit, when starting the low-voltage inverter operation, open through the same way open stop signal alright realize that main contactor closes earlier, main contactor is closed the back, the last self-checking of low-voltage inverter to after a period, low-voltage inverter starts the operation. When the low-voltage frequency converter stops running, the low-voltage frequency converter can be shut down firstly through one path of start-stop signals, and the main contactor is disconnected again after a period of time. The control circuit can realize that the starting and stopping of the main contactor and the frequency converter can be controlled by giving the starting and stopping signals all the way, can ensure the safety and the reliable operation of the frequency converter, and has simple circuit and fewer circuits. In addition, when the internal resistor of the frequency converter is overheated, the chopper breaks down or the starting control circuit is turned off, the coil of the main contactor loses power, the normally open main contact of the main contactor is disconnected, and the low-voltage frequency converter is powered off once. For the frequency converter loop which is not frequently started, when the starting control circuit is turned off, the main contact of the main contactor is disconnected, the frequency converter is not electrified once, the energy consumption can be reduced, and the energy is saved.
Because the situation is complicated and cannot be illustrated by a list, those skilled in the art can appreciate that there can be many examples in combination with the actual situation under the basic principle of the embodiments provided in the present application and that it is within the scope of the present application without sufficient inventive effort.
The embodiments are described in a progressive manner in the specification, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.
The control circuit of the low-voltage frequency converter provided by the present application is described in detail above. The principles and embodiments of the present application are explained herein using specific examples, which are provided only to help understand the method and the core idea of the present application. It should be noted that, for those skilled in the art, it is possible to make several improvements and modifications to the present application without departing from the principle of the present application, and such improvements and modifications also fall within the scope of the claims of the present application.
It is further noted that, in the present specification, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
Claims (10)
1. A control circuit of a low-voltage frequency converter is characterized by comprising:
the starting and stopping control circuit, the main contactor and the delay switch circuit; the time delay switch circuit is respectively connected with the start-stop control circuit, the coil of the main contactor, the normally open auxiliary contact of the main contactor and the low-voltage frequency converter, and the normally open main contact of the main contactor is connected between the low-voltage frequency converter and the three-phase alternating current;
the start-stop control circuit is used for controlling the time delay switch circuit to be powered on or powered off;
the time delay switch circuit is used for controlling the coil of the main contactor to be electrified when the time delay switch circuit is electrified, and triggering the low-voltage frequency converter to start operation after a first preset time after the coil of the main contactor is controlled to be electrified; when the time delay switch circuit loses power, the low-voltage frequency converter is triggered to stop running, and after the low-voltage frequency converter is triggered to stop running for a second preset time, the coil of the main contactor is controlled to lose power.
2. The control circuit of claim 1, wherein the time-delay switch circuit comprises:
the circuit comprises an intermediate switch circuit, a first delay switch circuit and a second delay switch circuit; the intermediate switch circuit is respectively connected with the start-stop control circuit and the first delay switch circuit, the first delay switch circuit is also connected with a normally-open auxiliary contact of the main contactor and the low-voltage frequency converter, and the second delay switch circuit is respectively connected with the start-stop control circuit and a coil of the main contactor;
the intermediate switch circuit is used for controlling the first time delay switch circuit to be powered on or powered off;
the second time delay switch circuit is used for controlling the coil of the main contactor to be immediately powered on when the second time delay switch circuit is powered on, and controlling the coil of the main contactor to be powered off after delaying the second preset time when the second time delay switch circuit is powered off;
the first time delay switch circuit is used for triggering the low-voltage frequency converter to start and operate after the first preset time when the first time delay switch circuit is electrified, and immediately triggering the low-voltage frequency converter to stop operating when the first time delay switch circuit is electrified.
3. The control circuit of claim 2, wherein the intermediate switching circuit comprises:
a first intermediate relay; the coil of the first intermediate relay is connected in series with the start-stop control circuit and then is connected between the live wire and the zero line; and the normally open auxiliary contact of the first intermediate relay is connected with the first time delay switch circuit.
4. The control circuit of claim 3, wherein the first time-delay switch circuit comprises:
a power-on time delay relay;
after being connected in series with the normally open auxiliary contact of the first intermediate relay and the normally open auxiliary contact of the main contactor, the coil of the power-on time delay relay is connected between the live wire and the zero line; and a normally open auxiliary contact of the power-on time delay relay is connected between a start-stop control terminal and a power supply terminal of the low-voltage frequency converter.
5. The control circuit of claim 4, wherein the second time-delay switch circuit comprises:
a power-off delay relay;
a coil of the power-off delay relay is connected in series with the start-stop control circuit and then is connected between the live wire and the zero line; and a normally open auxiliary contact of the power-off delay relay is connected in series with a coil of the main contactor and then is connected between the live wire and the zero line.
6. The control circuit of claim 5, wherein the start-stop control circuit comprises a first start button, a second start button, a first stop button, a second stop button, a three-gear selector switch and a remote control switch;
the first starting button and the first stopping button are connected in series and then connected with a first gear of the three-gear selector switch; the second starting button and the second stopping button are connected in series and then connected with a second gear of the three-gear selector switch; the remote control switch is connected with a third gear of the three-gear selector switch; the first starting button and the second starting button are connected with the normally open auxiliary contact of the first intermediate relay in parallel.
7. The control circuit of claim 6, further comprising:
the cabinet contactor runs the pilot lamp; the cabinet contactor operation indicator lamp is connected in series with the normally open auxiliary contact of the main contactor and then connected between the live wire and the zero line.
8. The control circuit of claim 7, further comprising:
the second intermediate relay and the frequency conversion operation indicator lamp of the cabinet; a coil of the second intermediate relay is connected in series with an operating contact of the low-voltage frequency converter and then connected between the live wire and the zero line, and a normally open auxiliary contact of the second intermediate relay is connected in series with the cabinet variable-frequency operating indicator lamp and then connected between the live wire and the zero line;
the third intermediate relay and the frequency conversion fault indicator lamp of the cabinet; third auxiliary relay's coil with connect after the trouble contact of low-voltage inverter establishes ties the live wire with between the zero line, third auxiliary relay's normally closed auxiliary contact with first auxiliary relay's coil and open stop after the control circuit establishes ties connect in the live wire with between the zero line, third auxiliary relay's normally open auxiliary contact with connect after this cabinet frequency conversion fault indication lamp establishes ties in the live wire with between the zero line.
9. The control circuit of claim 8, wherein the normally open auxiliary contact of the second intermediate relay and the normally open auxiliary contact of the third intermediate relay are further connected to a remote control terminal.
10. The control circuit of claim 9, further comprising:
the on-site contactor comprises an on-site contactor operation indicator lamp, an on-site frequency conversion operation indicator lamp and an on-site frequency conversion fault indicator lamp;
the on-site contactor operation indicator lamp is connected with the local contactor operation indicator lamp in parallel; the local variable frequency operation indicator lamp is connected with the local variable frequency operation indicator lamp in parallel; the local frequency conversion fault indicator lamp is connected with the local frequency conversion fault indicator lamp in parallel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121200961.9U CN215601216U (en) | 2021-05-26 | 2021-05-26 | Control circuit of low-voltage frequency converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121200961.9U CN215601216U (en) | 2021-05-26 | 2021-05-26 | Control circuit of low-voltage frequency converter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN215601216U true CN215601216U (en) | 2022-01-21 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202121200961.9U Active CN215601216U (en) | 2021-05-26 | 2021-05-26 | Control circuit of low-voltage frequency converter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN215601216U (en) |
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2021
- 2021-05-26 CN CN202121200961.9U patent/CN215601216U/en active Active
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