Fan fault monitoring circuit

Abstract

According to the fan fault monitoring circuit provided by the utility model, the contactor is connected with the circuit breaker, the on-off of the circuit and the operation state of the fan can be monitored through the pull-in state of the contactor, the thermal relay is connected with the fan, and whether the current in the circuit is overloaded or not is monitored through the on-off of the thermal relay. The wind pressure is monitored through the opening and closing state of the normally-closed contact of the wind pressure switch, a worker is reminded of timely processing through alarm, fault monitoring of the wind beam fan is achieved, the circuit is simple, and practicability is high.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of steelmaking, specifically relates to a fan fault monitoring circuit. BACKGROUND

[0002] In a certain process of a steelmaking plant, a ring heating furnace needs to be used to heat a steel pipe, and after the steel pipe is heated, the ring heating furnace needs to be cooled down, generally, a ring furnace wind beam fan is arranged to use the fan to air cool and cool down the ring heating furnace, in actual operation, the fan is used frequently in the plant, and the fan is prone to failure when being used, thereby affecting work efficiency, therefore, the fan needs to be monitored for failure.

[0003] Therefore, the utility model wants to solve the technical problem that how to monitor the fan for failure. UTILITY MODEL CONTENTS

[0004] In order to solve the technical problem that how to monitor the fan for failure, the utility model provides a fan fault monitoring circuit.

[0005] The specific scheme is as follows:

[0006] A fan fault monitoring circuit, including overload alarm module, power failure alarm module, fan alarm module and wind pressure alarm module, the overload alarm module, power failure alarm module, fan alarm module and wind pressure alarm module are connected to PLC controller respectively, and the PLC controller is electrically connected with the alarm module;

[0007] The fan alarm module includes a circuit breaker QS and a first contactor KM1, the upper end of the circuit breaker QS is connected with the power supply, the lower end of the circuit breaker QS is connected with the first contactor KM1, the first contactor KM1 includes a first auxiliary normally closed contact KM1, and the first auxiliary normally closed contact KM1 is electrically connected with the PLC controller;

[0008] The overload alarm module includes a first thermal relay FR1, the upper end of the first thermal relay FR1 is connected with the first contactor KM1, the lower end of the first thermal relay FR1 is connected with the first fan M1, and the first thermal relay FR1 includes a normally closed contact FR1, and the normally closed contact FR1 is electrically connected with the PLC controller;

[0009] The power failure alarm module includes a third contactor KM3, the third contactor KM3 is electrically connected with the circuit breaker QS, the third contactor KM3 includes a third auxiliary normally open contact KM3, and the third auxiliary normally open contact KM3 is electrically connected with the PLC controller;

[0010] The wind pressure alarm module includes a first wind pressure switch SP1, the first wind pressure switch SP1 includes a normally closed contact SP1, and the normally closed contact SP1 is electrically connected with the PLC controller.

[0011] Further comprising a second fan M2 connected in parallel with the first fan M1, the fan alarm module comprising a second contactor KM2, the overload alarm module comprising a second thermal relay FR2,

[0012] The upper end of the second contactor KM2 is connected with a circuit breaker QS, the lower end of the second contactor KM2 is connected with the upper end of the second thermal relay FR2, and the lower end of the second thermal relay FR2 is connected with the second fan M2.

[0013] The second contactor KM2 comprises a second auxiliary normally closed contact KM2, and the second auxiliary normally closed contact KM2 is electrically connected with the PLC controller.

[0014] The second thermal relay FR2 comprises a normally closed contact FR2, and the normally closed contact FR2 is electrically connected with the PLC controller.

[0015] The second fan M2 comprises a second wind pressure switch SP2, and a normally closed contact SP2 of the second wind pressure switch SP2 is electrically connected with the PLC controller.

[0016] The branch where the first contactor KM1, the first thermal relay FR1 and the first fan M1 are located is connected in parallel with the branch where the second contactor KM2, the second thermal relay FR2 and the second fan M2 are located.

[0017] The normally closed contact FR1 of the first thermal relay FR1 is connected in parallel with the normally closed contact FR2 of the second thermal relay FR2.

[0018] The normally closed contact SP1 of the first wind pressure switch SP1 is connected in parallel with the normally closed contact SP2 of the second wind pressure switch SP2.

[0019] The first auxiliary normally closed contact KM1 and the second auxiliary normally closed contact KM2 are connected in series to the PLC controller.

[0020] The upper end of the circuit breaker QS is connected with a three-phase power supply.

[0021] The beneficial effects of the utility model are as follows:

[0022] The utility model provides a fan fault monitoring circuit, set up contactor and circuit breaker connection, can monitor the on-off of circuit and the running state of fan through the attraction state of contactor, set up thermal relay and fan connection, whether the current in the monitoring circuit is overloaded through the on-off of thermal relay, monitor the wind pressure through the opening and closing state of normally closed contact of wind pressure switch, remind staff in time through alarm, realize the fault monitoring of fan beam fan, the circuit is simple, and the practicality is strong. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is the circuit connection drawing of the utility model.

[0024] Figure 2 a is the contact point connected with the PLC controller Figure 1 , Figure 2 b is the alarm signal connection of the utility model Figure 2 .

[0025] Figure 3 a is the contact point connected with the PLC controller Figure 1 , Figure 3 b is the alarm signal connection of the utility model Figure 2 .

[0026] circuit breaker QS,

[0027] first contactor KM1, first auxiliary normally closed contact KM1,

[0028] second contactor KM2, second auxiliary normally closed contact KM2,

[0029] third contactor KM3, third auxiliary normally open contact KM3,

[0030] first thermal relay FR1, normally closed contact FR1,

[0031] second thermal relay FR2, normally closed contact FR2,

[0032] first fan M1, second fan M2,

[0033] first air pressure switch SP1, normally closed contact SP1,

[0034] second air pressure switch SP2, normally closed contact SP2, DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the utility model. Obviously, the described embodiments are only part of the implementation of the utility model, rather than the whole implementation. Based on the embodiments of the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the utility model.

[0036] It should be noted that the signal transmission among the contactor, the PLC controller and the alarm in the utility model is the prior art, and the transmission between the contactor and the PLC controller is a switching signal.

[0037] As Figure 1 and Figure 2The utility model provides a fan fault monitoring circuit, including overload alarm module, power failure alarm module, fan alarm module and air pressure alarm module, overload alarm module, power failure alarm module, fan alarm module and air pressure alarm module are connected to PLC controller respectively, and PLC controller is connected to alarm module,

[0038] The fan alarm module comprises a circuit breaker QS and a first contactor KM1, the upper end of the circuit breaker QS is connected to a power supply, the lower end of the circuit breaker QS is connected to the first contactor KM1, the first contactor KM1 comprises a first auxiliary normally closed contact KM1, and the first auxiliary normally closed contact KM1 is electrically connected to the PLC controller.

[0039] The overload alarm module comprises a first thermal relay FR1, the upper end of the first thermal relay FR1 is connected to the first contactor KM1, the lower end of the first thermal relay FR1 is connected to a first fan M1, the first thermal relay FR1 comprises a normally closed contact FR1, and the normally closed contact FR1 is electrically connected to the PLC controller.

[0040] The power failure alarm module comprises a third contactor KM3, the third contactor KM3 is electrically connected to the circuit breaker QS, the third contactor KM3 comprises a third auxiliary normally open contact KM3, and the third auxiliary normally open contact KM3 is electrically connected to the PLC controller.

[0041] The air pressure alarm module comprises a first air pressure switch SP1, the first air pressure switch SP1 comprises a normally closed contact SP1, and the normally closed contact SP1 is electrically connected to the PLC controller.

[0042] The utility model provides a fan fault monitoring circuit, sets up contactor and circuit breaker connection, can monitor the on-off of circuit and the running state of fan through the attraction state of contactor, sets up thermal relay and fan connection, whether the current in monitoring circuit is overloaded through the on-off of thermal relay, monitors the air pressure through the opening and closing state of normally closed contact of air pressure switch, reminds the staff in time through the alarm and handles, has realized to the fault monitoring of fan beam fan, and the circuit is simple, and the practicality is strong.

[0043] As Figure 1 And Figure 2As shown, the second fan M2 is connected in parallel with the first fan M1, the fan alarm module comprises a second contactor KM2, the overload alarm module comprises a second thermal relay FR2, the upper end of the second contactor KM2 is connected with the circuit breaker QS, the lower end of the second contactor KM2 is connected with the upper end of the second thermal relay FR2, the lower end of the second thermal relay FR2 is connected with the second fan M2; the second contactor KM2 comprises a second auxiliary normally closed contact KM2, and the second auxiliary normally closed contact KM2 is electrically connected with the PLC controller; the second thermal relay FR2 comprises a normally closed contact FR2, and the normally closed contact FR2 is electrically connected with the PLC controller; the second fan M2 comprises a second wind pressure switch SP2, and the normally closed contact SP2 of the second wind pressure switch SP2 is electrically connected with the PLC controller; the branch where the first contactor KM1, the first thermal relay FR1 and the first fan M1 are located is connected in parallel with the branch where the second contactor KM2, the second thermal relay FR2 and the second fan M2 are located; the normally closed contact FR1 of the first thermal relay FR1 is connected in parallel with the normally closed contact FR2 of the second thermal relay FR2; and the normally closed contact SP1 of the first wind pressure switch SP1 is connected in parallel with the normally closed contact SP2 of the second wind pressure switch SP2.

[0044] The utility model discloses two fans, in actual work, only needs to use a fan to carry out air cooling temperature reduction to annular blast furnace, another fan is as spare, if using first fan M1 when working, when first fan M1 fails or the circuit where first fan M1 is located fails, leads to first fan M1 unable normal work, when second fan M2 is enabled to continue working, does not influence the normal work.

[0045] As Figure 2 b shows, the first auxiliary normally closed contact KM1 and the second auxiliary normally closed contact KM2 are connected in series to the PLC controller. In actual work, only one fan is needed to cool the annular blast furnace, so an alarm is only given when both fans cannot work normally.

[0046] As Figure 1 The upper end of the circuit breaker QS is connected with a three-phase power supply.

[0047] The specific working process of the utility model is as follows:

[0048] The utility model mainly carries out fault monitoring to the fan for cooling the annular heating furnace, sets up two fans, namely first fan M1 and second fan M2, in actual work, first fan M1 is used as working, and the following description is carried out with second fan M2 as spare.

[0049] As Figure 2 a shows,

[0050] The normally closed contact FR1 of the first thermal relay FR1 is connected to the PLC controller to monitor whether the circuit is overloaded. If the normally closed contact FR1 is in the closed state, the PLC controller is turned on to alarm, as shown by I1.

[0051] The third auxiliary normally open contact KM3 of the third contact KM3 is connected to the PLC controller to monitor whether the circuit is powered off. If the third auxiliary normally open contact KM3 is in the open state, the PLC controller is turned off to alarm, as shown by I2.

[0052] The first auxiliary normally closed contact KM1 of the first contact KM1 is connected to the PLC controller to monitor the running state of the first fan M1. If the first auxiliary normally closed contact KM1 is in the open state, the PLC controller is turned off, indicating that the first fan M1 is working normally, as shown by I3.

[0053] The second auxiliary normally closed contact KM2 of the second contact KM2 is connected to the PLC controller to monitor the running state of the second fan M2. If the second auxiliary normally closed contact KM2 is in the open state, the PLC controller is turned off, indicating that the second fan M2 is working normally, as shown by I4.

[0054] The normally closed contact SP1 of the first air pressure switch SP1 is connected to the PLC controller to monitor the air pressure of the first fan M1. If the normally closed contact SP1 is in the open state, the PLC controller is turned off to alarm, as shown by I5.

[0055] As shown by I3 and I4 in Figure 2 b, when I3 and I4 are both connected, the PLC controller is turned on to alarm. I1 and I1' are connected in parallel, and any one of I1 and I1' connected to the PLC controller will alarm.

[0056] Specifically, as shown by Figure 1 and Figure 2 ,

[0057] When the first fan M1 is working normally, the circuit breaker QS is turned on, the first contact KM1 is powered and attracted, the first auxiliary normally closed contact KM1 changes from the closed state to the open state, the first thermal relay FR1 is in the on state, and the normally closed contact FR1 changes from the closed state to the open state. At this time, neither the first auxiliary normally closed contact KM1 nor the normally closed contact FR1 transmits a signal to the PLC controller.

[0058] If the current in the circuit is too large, the first thermal relay FR1 will change from the on state to the off state, and the auxiliary normally closed contact FR1 will remain in the closed state. The PLC controller transmits a signal that the current is too large, and the PLC controller controls the alarm device to alarm. When I1 is connected, the PLC controller controls the alarm, realizing overload monitoring.

[0059] When the second fan M2 is working normally, the circuit breaker QS is on, the second contactor KM2 is energized and attracted, the second auxiliary normally closed contact KM2 changes from closed to open, the second thermal relay FR2 is on, and the normally closed contact FR2 changes from closed to open. At this time, neither the second auxiliary normally closed contact KM2 nor the normally closed contact FR2 transmits a signal to the PLC controller;

[0060] If the current in the circuit is too large, the second thermal relay FR2 will change from on to off, and the auxiliary normally closed contact FR2 remains closed. The PLC controller transmits a signal of excessive current and controls the alarm device to alarm. When I1' is on, the PLC controller controls the alarm, and overload monitoring is achieved.

[0061] Specifically, the reason for the excessive current in the circuit may be that the motor bearing driving the fan is damaged, or the motor blade is unbalanced and has high resistance. This type of motor failure will not cause the circuit breaker QS to be off. At this time, monitoring is performed through the first thermal relay FR1 or the second thermal relay FR2.

[0062] When the circuit breaker QS is on, the third contactor KM3 is energized and attracted, the third auxiliary normally open contact KM3 changes from open to closed, and the PLC controller transmits a signal of the attraction of the third contactor KM3.

[0063] When the circuit breaker QS is off, the third contactor KM3 loses power and is off, and the third auxiliary normally open contact KM3 remains open. The PLC controller does not transmit a signal at this time. The PLC controller does not receive the signal of the third auxiliary normally open contact KM3, and the PLC controller controls the alarm device to alarm. When I2 is off, the PLC controller controls the alarm, and power-off monitoring is achieved.

[0064] When the first fan M1 is working normally, the circuit breaker QS is on, the first contactor KM1 is energized and attracted, the first auxiliary normally closed contact KM1 changes from closed to open, the first thermal relay FR1 is on, and the normally closed contact FR1 changes from closed to open. Neither the first auxiliary normally closed contact KM1 nor the normally closed contact FR1 transmits a signal to the PLC controller.

[0065] When the first fan M1 fails, the circuit breaker QS will be off. At this time, the third contactor KM3 loses power and is off, and the third auxiliary normally open contact KM3 remains open. The PLC controller alarms because it does not receive the signal of the third auxiliary normally open contact KM3. The staff checks the fault, turns on the circuit breaker QS and the second contactor KM2, the second contactor KM2 is energized and attracted, the second auxiliary normally closed contact KM2 changes from closed to open, the second thermal relay FR2 is on, and the second fan M2 works normally.

[0066] When the second fan M2 fails, the circuit breaker QS will be disconnected, and the third contactor KM3 will lose power and be disconnected. The third auxiliary normally open contact KM3 remains in the open state unchanged. The PLC controller will not receive the signal from the third auxiliary normally open contact KM3, and will alarm. At the same time, the first contactor KM1 loses power and is disconnected, the first auxiliary normally closed contact KM1 remains in the closed state unchanged, the second contactor KM2 loses power and is disconnected, and the second auxiliary normally closed contact KM2 remains in the closed state unchanged. The first auxiliary normally closed contact KM1 and the second auxiliary normally closed contact KM2 are connected to the PLC controller, respectively. The PLC controller controls the alarm device to alarm. When I3 and I4 are both connected, the PLC controller controls the alarm, and the fan failure monitoring is realized.

[0067] Specifically, the fan failure may be due to a problem with the circuit or a jammed motor driving the fan, causing the circuit breaker QS to be disconnected. When the motor fails, the circuit breaker QS will trip due to overload or short circuit to protect the circuit and equipment from further damage. The specific reasons include: when the motor is overloaded, the current will increase, causing the circuit breaker QS to trip due to abnormal current; internal short circuit of the motor can cause a sharp increase in current, triggering the circuit breaker QS to disconnect; long-term high-load operation or high-temperature environment can cause the motor to overheat, causing the circuit breaker QS to prevent the motor from being damaged.

[0068] When the first fan M1 is working normally, the circuit breaker QS is connected, the first contactor KM1 is powered and attracted, the first auxiliary normally closed contact KM1 changes from closed to open state, the first thermal relay FR1 is in the connected state, and the normally closed contact FR1 changes from closed to open state. When the wind pressure of the first fan M1 is normal, the normally closed contact SP1 of the first fan M1 is in the closed state, connecting the PLC controller to transmit the signal that the wind pressure is normal.

[0069] When the wind pressure of the first fan M1 is too small, the normally closed contact SP1 of the first fan M1 changes from closed to open state, disconnecting the PLC controller from transmitting the signal. At this time, the PLC controller does not receive the signal from the normally closed contact SP1, and the PLC controller controls the alarm device to alarm. When I5 is disconnected, the PLC controller controls the alarm, and the wind pressure monitoring is realized.

[0070] When the second fan M2 is working normally, the circuit breaker QS is connected, the second contactor KM2 is powered and attracted, the second auxiliary normally closed contact KM2 changes from closed to open state, the second thermal relay FR2 is in the connected state, and the normally closed contact FR2 changes from closed to open state. When the wind pressure of the second fan M2 is normal, the normally closed contact SP2 of the second fan M2 is in the closed state, connecting the PLC controller to transmit the signal that the wind pressure is normal.

[0071] When the air pressure of the second fan M2 is too small, the normally closed contact SP2 of the second fan M2 is changed from closed to open state, the PLC controller does not transmit signals, at this time, the PLC controller cannot receive the signal of the normally closed contact SP2, the PLC controller controls the alarm device to alarm, that is, when I5' is disconnected, the PLC controller controls the alarm, and the air pressure monitoring is realized.

[0072] ‌The air pressure switch controls the on-off of the switch by measuring the change of the air pressure, so as to achieve the purpose of adjusting the air volume and controlling the operation of the equipment. The air pressure switch has two detection ports, i.e. a positive pressure detection port and a negative pressure detection port, and the cavity is divided into a positive pressure cavity and a negative pressure cavity, and the two cavities are isolated by a film. When there is a pressure source, the film moves to touch the micro switch, so as to achieve the purpose of opening / closing.

[0073] The utility model discloses still can set up two fans, a fan pressure switch, as Figure 3 a and Figure 3 b show, connect the fan pressure switch on the main pipeline of two fans, so realize the monitoring of the air pressure of two fans by one fan pressure switch, two fan pressure switches are arranged in the embodiment, and one fan pressure switch corresponds to one fan, as Figure 2 a and Figure 2 b show.

[0074] The thermal relay is a kind of protection electrical apparatus using the thermal effect of current, mainly used for the overload protection of motor. When motor is overloaded, the current of heating element in thermal relay increases, makes bimetallic strip bend, drives normally closed contact to act, to disconnect circuit, protects motor. Thermal relay is composed of heating element (resistance wire), bimetallic strip, conducting part and normally closed contact, bimetallic strip is composed of two metal sheets with different linear expansion coefficients, and it will bend to the side with lower expansion coefficient when temperature rises, and when bending reaches a certain degree, it will push connecting rod to act, and drive normally closed contact to act, to disconnect control circuit.

[0075] When motor is normally operated, the heat generated by heating element makes bimetallic strip bend, but it is not enough to make thermal relay act. Only when motor is overloaded, the heat generated by heating element makes bimetallic strip bend to a greater extent, and pushes guide plate to move, so that normally closed contact is disconnected, and the power supply of motor is cut off, to play a protection role.

[0076] The technical means disclosed in the utility model scheme is not limited to the technical means disclosed in the above embodiment, and also includes the technical scheme composed of any combination of the above technical features. It should be noted that, for ordinary skilled persons in the art, without departing from the principle of the utility model, some improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the utility model.

Claims

1. A fan fault monitoring circuit, characterized by: The overload alarm module, the power-off alarm module, the fan alarm module and the air pressure alarm module are connected to the PLC controller. The fan alarm module comprises a circuit breaker QS and a first contactor KM1. The overload alarm module comprises a first thermal relay FR1. The power-off alarm module comprises a third contactor KM3. The air pressure alarm module comprises a first air pressure switch SP1.

2. The fan fault monitoring circuit of claim 1, wherein: The second fan M2 is connected in parallel with the first fan M1. The fan alarm module comprises a second contactor KM2. The second contactor KM2 is connected to the circuit breaker QS. The second contactor KM2 is connected to the second thermal relay FR2. The second contactor KM2 comprises a second auxiliary normally closed contact KM2. The second thermal relay FR2 comprises a normally closed contact FR2. The second fan M2 comprises a second air pressure switch SP2. The first contactor KM1, the first thermal relay FR1 and the first fan M1 are connected in parallel with the second contactor KM2, the second thermal relay FR2 and the second fan M2. The normally closed contact FR1 of the first thermal relay FR1 is connected in parallel with the normally closed contact FR2 of the second thermal relay FR2.

3. The fan fault monitoring circuit of claim 1, wherein: The normally closed contact SP1 of the first air pressure switch SP1 is connected in parallel with the normally closed contact SP2 of the second air pressure switch SP2.

4. The fan fault monitoring circuit of claim 1, wherein: The first auxiliary normally closed contact KM1 and the second auxiliary normally closed contact KM2 are connected in series to the PLC controller. The upper end of the circuit breaker QS is connected to a three-phase power supply.

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